/*============================================================================*/ /***************************** MISSION TEMPLATE *******************************/ /* MODIFICATIONS: */ /* 920929 RMONARREZ */ /* Generated from database */ /* Template: Mission Template Rev: 19890121 */ /* Note: The following templates form part of a standard set */ /* for the submission of a mission to the PDS. */ /* Hierarchy: MISSION */ /* MSNINFO */ /* MSNPHSINFO */ /* MSNREFINFO */ /* REFERENCE */ /* REFAUTHORS */ OBJECT = MISSION MISSION_NAME = "PIONEER VENUS" OBJECT = MSNINFO MISSION_START_DATE = 1978-05-20 MISSION_STOP_DATE = 1992-10-07 MISSION_ALIAS_NAME = "P12" MISSION_DESC = " Pioneer Venus Overview Pioneer Venus consists of two basic spacecraft: Orbiter and Multiprobe [1]. The latter was separated into five separate vehicles near Venus. These were the probe transporter (called the Bus), a large atmospheric entry probe (dubbed Sounder) and three identical smaller probes (called North, Day, and Night in accordance with their entry locations). At Venus all six spacecraft communicated directly back to the Earth-based Deep Space Network (DSN) and, in the case of the Multiprobe mission, to two special receiving sites near Guam and Santiago (Chile). The Orbiter was launched on May 20, 1978, encountered Venus on December 4, 1978, was inserted into orbit on that same day after a Type II interplanetary cruise trajectory lasting 198 days and covering more than 500 x 106 km. Twelve scientific experiments were included in the instrumentation payload and a few radioscience investigations were planned using the S-band telemetry signal carrier and a special X-band beacon included as part of the spacecraft hardware. Scientific observations were made both in-cruise and in-orbit. The nominal in-orbit mission was designed to extend for one Venus year (243 days). At the time this Special Issue was submitted for publication the nominal mission was complete and the Orbiter was continuing into an extended mission phase. It appears that sufficient fuel remains to permit full operation through calendar year 1980, at least. During the nominal mission all but two experiments operated 100 percent successfully. One, the Radar Mapper, produced unusable data for a 32-day period from December 18, 1978 to January 19, 1979. the data lost will be acquired during the extended Orbiter mission. The other, the Infrared Radiometer, failed to operate after February 14, 1979, but had collected and enormous quantity of valuable information prior to that date. The Multiprobe was launched on August 8, 1978, encountered Venus on December 9, 1978 (just five days following the Orbiter insertion) after a Type I interplanetary cruise trajectory lasting 123 days and covering 330 x 106 km. The Sounder was released from the Bus on November 15, 1978, and the three small probes were released simultaneously on November 19, 1978. All probes entered(200-km altitude) the Venus upper atmosphere within a time span of about 11 min and descended to the surface in a period from 53 to 56 min, all the time performing scientific observations. The Bus made a delayed (~90 min) entry relative to the probes into Venus' upper atmosphere and burned up at about 110-km altitude since it was not protected, as were the probes, with entry heat shields. Scientific observations were made during the one-minute interval from 700 to 110 km. Although not designed for `survival' after impact, the Day probe managed to transmit for over 67 min on the surface (it in fact continued to transmit after the Bus transmission ceased). Seven scientific experiments were included in the Sounder instrumentation payload, three identical experiments in each small probe, and two in the Bus. Again, radioscience experiments were performed using, separately or together, the S-band telemetry signal carriers emanating from the spacecraft and received at the Earth-based tracking stations. In general, all instruments performed nominally, although certain instruments behaved anomalously on all four probes near the surface. The scientific payload, Principal Investigator, and his affiliation are listed in Table I for each Pioneer Venus spacecraft. This Special Issue is primarily devoted to short descriptions of the instruments listed. All are contained herein with one exception: Orbiter Cloud Photopolarimeter. Detailed instrument descriptions for this experiment have been published [2]. Before proceeding with descriptions of the individual instruments, four special archival-type reports are included. The first deals with spacecraft design and operation [3]. The Pioneer Venus spacecraft were unique and very special design features and operational modes needed to be incorporated. These are summarized therein. Similarly, telemetry recovery, particularly for the Multiprobe mission, was unusually demanding and unique techniques were developed and employed. The Orbiter and Multiprobe systems are described in two papers [4], [5]. Finally, a special ground data handling and distribution system, developed after an Atmospheric Explorer program model, was developed and is described [6]. Only one radioscience experiment description is specifically presented [7]. The necessary information for the others are contained in the telemetry recovery papers [3], [4]. It should be noted that neither the scientific objectives nor the scientific results for the Pioneer Venus program are described or discussed in detail. The objectives have been published elsewhere [8], [9]. The reader is referred to two special journal issues devoted to initial scientific results published to data [10], [11]. References [1] L. Colin and C.F. Hall, Space Sci. Rev., vol. 20, no. 3, p. 283, May 1977. [2] E.E. Russell, L. A. Watts, S. F. Pellicori, and D. L. Coffeen, 'Orbiter cloud photopolarimeter for the Pioneer Venus mission,' Proc. Soc. Photo-Optical Instrum. Eng., vol. 112, Aug. 1977. L. D. Travis, 'Imaging and polarimetry with the Pioneer Venus orbiter cloud photopolarimeter,' Proc. Photo-Optical Instrum. Eng., vol. 183, 1979. [3] G. J. Nothwang, 'Pioneer Venus Spacecraft Design and Operation,' IEEE Trans. on Geosci. and Remote Sensing, vol. GE-18, no. 1 pp 5-10, January, 1980. [4] A. L. Berman and R. Ramos, 'Pioneer Venus Occultation Radio Science Data Generation,' IEEE Trans. on Geosci. and Remote Sensing, vol. GE-18, no. 1 pp 11-14. [5] R. B. Miller and R. Ramos, 'Pioneer Multiprobe Entry Telemetry Recovery,' IEEE Trans. on Geosci. and Remote Sensing, vol. GE-18, no. 1 pp 15-19, January, 1980. [6] J. A. Ferandin, J. Brownwood, C. Weeks, and R. Pak, 'Pioneer Venus Unified Abstract Data Library and Quick Look Data Delivery System,' IEEE Trans. on Geosci. and Remote Sensing, vol. GE-18, no. 1 pp 19-27, January, 1980. [7] J. R. Smith and R. Ramos, 'Data Acquisition for Measuring the Wind on Venus from Pioneer Venus', IEEE Trans. on Geosci. and Remote Sensing, vol. GE-18, no. 1 pp 126-130, January, 1980. [8] Space Sci. Rev., vol. 20 no. 3, May 1977. [9] Space Sci. Rev., vol. 20 no. 4, June 1977. [10] Science, vol. 203 no. 4382, Feb. 23 1979. [11] Science, vol. 205 no. 4401, July 6 1979." MISSION_OBJECTIVES_SUMMARY = " The two Pioneer flights to Venus were intended to explore the atmosphere of the planet, to study its surface using radar, and to determine its global shape and internal density distribution. The Pioneer Venus Orbiter was designed to operate for 8 months or more making direct and remote sensing measurements. The Pioneer Venus Multiprobe spacecraft was designed to separate into 5 separate atmospheric entry craft some 12.9 million km (8 million miles) before reaching Venus. Each probe craft was designed to make measurements of the characteristics of the atmosphere from its highest regions to the surface of the planet in a period of a little more than 2 hours at points spread over the Earth-facing hemisphere of the planet." OBJECT = MSNPHSINFO SPACECRAFT_ID = PVO TARGET_NAME = VENUS MISSION_PHASE_TYPE = "ORBITAL OPERATIONS" SPACECRAFT_OPERATIONS_TYPE = "ORBITER OPERATIONS" MISSION_PHASE_START_TIME = 1978-12-05 MISSION_PHASE_STOP_TIME = 1992-10-02 MISSION_PHASE_DESC = " This mission phase 'orbiter operations' describes the entire mission of the Orbiter spacecraft." END_OBJECT = MSNPHSINFO OBJECT = MSNPHSINFO SPACECRAFT_ID = PVMP TARGET_NAME = VENUS MISSION_PHASE_TYPE = ENCOUNTER SPACECRAFT_OPERATIONS_TYPE = "ATMOSPHERIC PROBE" MISSION_PHASE_START_TIME = 1978-12-07 MISSION_PHASE_STOP_TIME = 1978-12-07 MISSION_PHASE_DESC = " This mission phase 'encounter' describes all operations of the 5 separate probe components of the Multiprobe component of the Pioneer Venus mission." END_OBJECT = MSNPHSINFO END_OBJECT = MSNINFO OBJECT = MSNREFINFO REFERENCE_KEY_ID = "COLIN1980B" OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "MISSION DESCRIPTION" JOURNAL_NAME = "IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Colin, L., 'Pioneer Venus Overview', IEEE Transactions on Geoscience and Remote Sensing, January 1980, Vol GE-18, No. 1, p5-10" OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "LAWRENCE COLIN" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = MSNREFINFO END_OBJECT = MISSION /*============================================================================*/ /*********************** SPACECRAFT TEMPLATE **********************************/ /* MODIFICATIONS: */ /* Template: Spacecraft Template Rev: 19890121 */ /* Note: The following templates form part of a standard */ /* set for the submission of a spacecraft to the PDS. */ /* Hierarchy: SPACECRAFT */ /* SCINFO */ /* PLATFORM */ /* SCREFINFO */ /* REFERENCE */ /* REFAUTHORS */ OBJECT = SPACECRAFT SPACECRAFT_ID = "PVO" OBJECT = SCINFO LAUNCH_DATE = 1978-05-20 INSTRUMENT_HOST_NAME = "PIONEER VENUS ORBITER" INSTRUMENT_HOST_TYPE ="SPACECRAFT" SPACECRAFT_DESC = " Extracted from: `Pioneer Venus Spacecraft Design and Operation' IEEE Transactions on Geoscience and Remote Sensing, vol. GE-18, No. 1, January 1980 By George J. Nothwang I. Introduction The Pioneer Venus mission objectives dictated the requirement for two spacecraft designs designated the Orbiter and the Multiprobe. (The Multiprobe is defined as the Bus with the one Large Probe and three identical Small Probes attached in the launch/cruise configuration.) The conceptual designs of these spacecraft resulted from Phase B studies conducted from October 1972 to July 1973, and after selection of the spacecraft contractor, Hughes Aircraft Company, in February 1974, a spacecraft conceptual design review was conducted in November 1974. The Orbiter and Multiprobe utilized the same designs to the maximum extent possible to minimize costs. In addition, designs of subsystems or portions of subsystems from previous spacecraft designs (such as OSO and Intelsat) were utilized to the maximum extent possible with little or no modifications. This commonality in the two spacecraft designs also resulted in certain amounts of commonality in ground test equipment and test software as well as commonality in spacecraft flight operations and associated software. A photograph of the Multiprobe (foreground) and Orbiter in the manufacturer's facility (Hughes Aircraft Company, El Segundo, CA) is shown on the cover. II. Spacecraft Design and Operation The design and operation of the orbiter will be described first and the Multiprobe second. The Multiprobe description and operation will then be separated into the Bus, Large Probe, and Small Probe segments. A. Orbiter The general configuration of the Orbiter after launch by an Atlas SLV-3D/Centaur D-1 AR is shown in Fig. 1. The weight of the spacecraft and 12 scientific instruments immediately after separation from the launch vehicle was 553 kg (1220 lbs) which included 32 kg (70 lbs) of hydrazine for trajectory correction maneuvers and spin axis orientation and 179 kg (398 lbs) of orbit insertion motor solid propellant and inserts. Immediately after separation from the Centaur launch vehicle, the spacecraft was automatically spun up to approximately 6.5 rpm and after establishing satisfactory ground communications with the Deep Space Network (DSN), commands to deploy the magnetometer boom and to orient the spacecraft spin axis perpendicular to the ecliptic were transmitted. The nominal spin rate was increased to 15 rpm with the spin axis (+Z axis) pointed in a northerly direction and this attitude was maintained in the cruise phase of the mission except during short periods for trajectory corrections. Communications were normally maintained through the despun high-gain antenna to maximize the data rates. Two days before reaching Venus, the spacecraft was configured for orbit insertion. Communications were transferred to the omni antennas and the spacecraft including the high- gain antenna spun up to 52 rpm to provide acceptable gyroscopic stiffness during motor burn. Since the motor burn had to occur while the spacecraft was being occulted by Venus, commands were loaded and subsequently executed from the on-board stored command logic without real-time communication. Orbit insertion was achieved with an orbit inclination of 105 degrees with respect to the equator and a nominal orbit period of 24 h. After reacquisition of the spacecraft from occultation, a series of maneuvers were performed to point the spacecraft spin axis (=Z axis) perpendicular to the ecliptic in a southerly direction, despin the high-gain antenna, and slow the spacecraft spin rate to about 5 rpm, the preferred rate for scientific data. Nominal orbital operations were then begun which include orbit periapsis and period adjustments and spacecraft attitude adjustments. The Orbiter spacecraft consists of the following subsystems and functions: Mechanical function (including the Spacecraft Structure), Thermal Function (accomplished by the Structure/Harness Subsystem), Controls Subsystem, Propulsion Subsystem, Data Handling subsystem, Command Subsystem, Communications Subsystem, and Power Subsystem. 1) Mechanical: The mechanical features of the spacecraft can be described by six basic assemblies, as seen in Fig. 1. The despun antenna assembly, the bearing and power transfer assembly (BAPTA), the BAPTA support structure, equipment shelf, substrate (solar array), orbit insertion motor (OIM) and its case, and thrust tube. The shape and equipment layout conform to the basic mechanical requirements of a spin-stabilized vehicle. The solar cells on the cylindrical solar panel, antenna orientations, and thrust vector orientations provide efficient power, communications, and maneuverability while the Orbiter is spinning in its cruise and orbit attitudes. 2) Thermal: The thermal design is based on isolating the equipment from the external solar extremes experienced during the mission. (Solar intensity increases by a factor 1.98 from Earth to Venus). Commandable heaters are provided to maintain the orbit insertion motor and safe and arm device within their specified temperature ranges, to prevent possible freezing and hydrazine monopropellant , and to make up heat balance should there occur an inadvertent trip of nonessential spacecraft loads. Fifteen thermostatically controlled thermal louvers are mounted on the aft side of the equipment shelf beneath units having high dissipations. 3) Controls: The controls subsystem provides the sensing logic and actuators to accomplish the following stabilization, control, and reference functions: a) spin axis attitude determination (via use of slit field-of-view type sun sensors and star sensors and star sensors), science roll reference signals generation, and spin period measurements; b) control of thrusters for spin axis attitude maneuvers , spin speed control, and spacecraft velocity maneuvers; c) high-gain antenna azimuth despin control and elevation positioning to a desired earth line-of- sight pointing ; additionally, antenna slew control for open-loop tracking of the Earth line-of- sight; d) magnetometer sensor deployment; e) nutational damping, via use of a partially filled tube of liquid Freon E3. 4) Propulsion: The propulsion subsystem provides the hydrazine monopropellant storage, pressurization, distribution lines, isolation valves, filtering, and thruster assemblies used to accomplish Orbiter maneuvers throughout the mission. 5) Data Handling: The data handling subsystem conditions and integrates into command- selectable (choice of thirteen fixed and one programmable) formats, all analog and digital telemetry data (248 assigned channels) originating in the subsystems and science instruments. The selected format of the all-digitized data modulates a 16 384-Hz subcarrier at a command- selectable (choice of thirteen rates between 8 and 4096 bps) bit rate. The resulting information is routed to the communications subsystem for modulation of the downlink S-band carrier. The data handling subsystem includes a data memory, consisting of two data storage units (DSU) that is intended primarily for use during any occultation. Data are stored or read out at the commanded bit rate. Each DSU has a capacity of 524 288 bits (equivalent to 1024 telemetry minor frames). 6) Command: The command subsystem decodes all commands received via the communications subsystem at the fixed rate of 4 bps, and either stores the command for later execution or routes the command in real time to the addressed destination. Each of the 381 assigned commands is either completely decoded (discrete-type command) by the command subsystem and the execution command generated, or is partially decoded (quantitative-type command) by the command subsystem and the command is routed to the addressed destination for final decoding. 7) Communications: The communications subsystem provides radiation reception and transmission capabilities for the command and telemetry information. The uplink command capability is maintained by modulating an S-band carrier of approximately 2.115 GHz. The downlink telemetry modulates an S-band carrier approximately 2.295 GHz. There are two redundant reception channels; each includes a hemispherically omnidirectional antenna (aft or forward) that spatially supplements the other to produce total spatial coverage. Optionally by command, the forward antenna is replaceable by a high-gain antenna or a high-gain back-up antenna. The S-band downlink is assignable by command to any one of the aft or forward omnidirectional antennas, or to the high-gain or high-gain back-up (directional) antennas. Its frequency is a multiple of the uplink frequency; or in the absence of an uplink signal, it is a multiple of a crystal oscillator located in the receiver. The downlink may also be transmitted via any one of, or some pairs of, four 10-W power amplifiers. There is an additional transmitter in the X-band range (the frequency is 11/3 of the S-band downlink frequency) that is for use in occultation measurements. The transmission is unmodulated through the high-gain antenna only. 8) Power: The power subsystem provides semiregulated 28 V 10 percent to all spacecraft loads (including science instruments). The primary source of power is the main solar array. When the solar panel output cannot provide adequate power for all spacecraft loads (at low sun angles and during eclipses), the two nickel/cadmium batteries (each rated at 7.5 Ah full capacity) come on line automatically through the discharge regulators. Battery energy is replenished through a small boost charge array. The power interface unit provides power switching for the propulsion heaters and OIM heaters. It also contains fuses for these circuits and the science instruments input power lines. Power is distributed on four separate power buses. If a spacecraft over-current condition or under-voltage on either battery occurs, loads are removed to protect the spacecraft from potential catastrophic failure by tripping off buses in the following sequence: science, switched loads, and transmitter. This leaves only those loads that are absolutely essential to spacecraft survival in a continuously powered ON mode. The RF transmitters and exciters are on the transmitter bus. Controls and data handling units are on the switched loads bus. Scientific instruments are on the science bus. Command units, OIM and propulsion heaters, power conditioning units, and spacecraft receivers are on the essential bus. Excitation for the pyro bus is derived from a battery tap located 16 cells (of a total of 24) from the ground reference level. The bus voltage is limited to 30.0 V by seven shunt limiters that dissipate all excess solar panel capacity in load resistors mounted on the solar panel substrate and equipment shelves." END_OBJECT = SCINFO OBJECT = PLATFORM PLATFORM_OR_MOUNTING_NAME = "MAGNETOMETER BOOM" PLATFORM_OR_MOUNTING_DESC = " An 4.8 meter long boom (188.9 inches) that was unfurled and extended automatically after launch. The magnetometer boom is located 240 degrees from the X-axis of the spacecraft coordinate system, measured in towards the Y-axis (in the spin direction) of the spin plane (XY). The total distance from the end of the boom to the orbiter spin axis is 5.94 meters (234.0 inches)" END_OBJECT = PLATFORM OBJECT = SCREFINFO REFERENCE_KEY_ID = NOTHWANG1980 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "SPACECRAFT DESIGN" JOURNAL_NAME = "IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Nothwang, G.T., `Pioneer Venus Spacecraft Design and Operation', IEEE Transactions on Geoscience and Remote Sensing, January 1980, Vol GE-18, No. 1, p5-10" OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "GEORGE J. NOTHWANG" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = SCREFINFO END_OBJECT = SPACECRAFT /*============================================================================*/ /**********Coordinate System Template******************************************/ /* MODIFICATIONS: */ /* 930315 -- SJOY updated totally. */ /* 930526 -- SJOY added remaining coordinate systems for use in SEDR */ /* CD-ROM production. All PVO coordinate systems now defined. */ /* Template: Coordinate System Template Rev: 19890121 */ /* Note: The following templates form part of a standard */ /* set for the submission of a Coordinate System */ /* to the PDS. */ /* Hierarchy: COORDINATE */ /* COORDINFO */ /* VECTOR */ /* VECTORCOMP */ /* VECTORD */ /* /**************************************************************************** /* Spinning S/C Coordinates /**************************************************************************** /* OBJECT = COORDINATE COORDINATE_SYSTEM_ID = PVO_SSCC OBJECT = COORDINFO COORDINATE_SYSTEM_NAME = "PVO SPINNING SPACECRAFT COORDS" COORDINATE_SYSTEM_CENTER_NAME = PVO COORDINATE_SYSTEM_REF_EPOCH = "N/A" COORDINATE_SYSTEM_DESC = " Spacecraft coordinates (Xs, Ys, Zs) are used to describe the physical mounting locations of the Sun sensors, the star sensor, and the experiment sensors. The spacecraft coordinate system is centered at the spacecraft center of mass and rotates with the spacecraft. The Xs-Ys plane is parallel to the plane of the spacecraft equipment shelf. The positive Zs axis points out the top of the spacecraft. The positive Ys axis coincides with the split line of the equipment shelf. With no spacecraft wobble or nutation, the spacecraft positive Zs axis will coincide with the spin axis and the equipment shelf will thus be perpendicular to the spin axis." END_OBJECT = COORDINFO OBJECT = VECTOR VECTOR_COMPONENT_TYPE = SSCC_X OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = XS REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = "N/A" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " The +Xs axis of the PVO spacecraft coordinate system is defined to lie in a plane parallel to the equipment shelf at 90 degrees to the split-line of the equipment shelf measured in the direction opposing the spacecraft spin direction." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = SSCC_Y OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = YS REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " The +Ys axis of the PVO spacecraft coordinate system is defined to lie in a plane parallel to the equipment shelf and follow the split-line of the equipment shelf." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = SSCC_Z OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = ZS REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " The positive Zs axis points out the top of the spacecraft. With no spacecraft wobble or nutation, the spacecraft positive Zs axis will coincide with the spin axis and the equipment shelf will thus be perpendicular to the spin axis." END_OBJECT = VECTORD END_OBJECT = VECTOR END_OBJECT = COORDINATE /* /**************************************************************************** /* Inertial S/C Coordinates /**************************************************************************** /* OBJECT = COORDINATE COORDINATE_SYSTEM_ID = PVO_ISCC OBJECT = COORDINFO COORDINATE_SYSTEM_NAME = "PVO INERTIAL SPACECRAFT COORDS" COORDINATE_SYSTEM_CENTER_NAME = PVO COORDINATE_SYSTEM_REF_EPOCH = "UNK" /*1950.0*/ COORDINATE_SYSTEM_DESC = " The inertial spacecraft coordinate system for the PVO spacecraft is same coordinate system as the spinning spacecraft coordinate system (SSCC) except that it does not spin with the spacecraft. Thus the Spin axis or positive Z axis direction is the same in both systems and it points out the top (toward the BAFTA assembly) of the spacecraft. The axes in the spin plane are defined as follows: The X-Z plane is defined to contain the spacecraft-Sun vector with the positive X direction being sunward, and the coordinate system is defined to be right-handed. The transformation from SSCC to ISCC is: _ _ | cos(p) -sin(p) 0 | | sin(p) cos(p) 0 | | 0 0 1 | _ _ where p is the spin phase angle measured in ISSC coordinates." END_OBJECT = COORDINFO OBJECT = VECTOR VECTOR_COMPONENT_TYPE = ISCC_X OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = PVO_X REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " The X component of the PVO spacecraft coordinate system lies in the sunward direction, such that the X-Z plane contains the sun. The X component is measured positive towards the sun." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = ISCC_Y OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = PVO_Y REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " The Y component is formed by the right-handed vector cross product of the X and Z unit vectors where the Z axis is defined as the spacecraft spin axis and the X-Z plane contains the Sun." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = ISCC_Z OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = PVO_Z REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " The Z axis is defined to be anti-parallel to the spacecraft spin axis during orbital operations." END_OBJECT = VECTORD END_OBJECT = VECTOR END_OBJECT = COORDINATE /**************************************************************************** /* VSO Coordinates /**************************************************************************** /* MODIFICATIONS: /* 930223 -- MKNIFFIN /* created template OBJECT = COORDINATE COORDINATE_SYSTEM_ID = VSO OBJECT = COORDINFO COORDINATE_SYSTEM_NAME = "VENUS SOLAR ORBITAL COORDS" COORDINATE_SYSTEM_CENTER_NAME = "VENUS" COORDINATE_SYSTEM_REF_EPOCH = "N/A" COORDINATE_SYSTEM_DESC = " The VSO coordinate system is a Cartesian coordinate system centered on Venus. The components of this coordinate system are as follows: The X axis direction points from the center of Venus to the Sun, taken positive towards the Sun, the Z axis is parallel to the northward pole of the Venus orbital plane, the Y axis completes the right-handed set and points towards dusk. Locations of bodies (spacecraft) given in VSO coordinates are usually represented in units of Venus radii where Rv = 6052 km." END_OBJECT = COORDINFO OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = VSO_X REFERENCE_OBJECT_NAME = SUN REFERENCE_TARGET_NAME = VENUS VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " The X component of the VSO coordinate system is taken to be positive in the direction of the Sun measured along the Venus- Sun line. The units are commonly given in Venus Radii where Rv = 6052 km" END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = VSO_Y REFERENCE_OBJECT_NAME = SUN REFERENCE_TARGET_NAME = VENUS VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " The Y component of the VSO coordinate system is taken to be positive in the direction opposing orbital motion (dusk) and lying in the orbital plane of Venus. The units are commonly given in Venus Radii where Rv = 6052 km" END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = VSO_Z REFERENCE_OBJECT_NAME = SUN REFERENCE_TARGET_NAME = VENUS VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " The Z component of the VSO coordinate system is taken to be parallel to the pole of the Venus orbital plane and positive in the northward direction (upward normal). The units are commonly given in Venus Radii where Rv = 6052 km" END_OBJECT = VECTORD END_OBJECT = VECTOR END_OBJECT = COORDINATE /**************************************************************************** /* Inertial Spherical Coordinates - Equatorial /**************************************************************************** OBJECT = COORDINATE COORDINATE_SYSTEM_ID = ISC_EQTR OBJECT = COORDINFO COORDINATE_SYSTEM_NAME = "EQUATORIAL INERT SPHRCL COORDS" COORDINATE_SYSTEM_CENTER_NAME = "EARTH" COORDINATE_SYSTEM_REF_EPOCH = "UNK" /* 1950.0 */ COORDINATE_SYSTEM_DESC = " The EQUATORIAL INERTIAL SPHERICAL COORDINATE system is defined by the equatorial plane of the Earth for the reference epoch of 1950.0. The principal direction vectors of this system are the Earth's Equatorial Pole and the Vernal Equinox direction. The components of the coordinate system are: 1) Radius: Distance from the reference body to the spacecraft. 2) Declination: The angle between the reference body-spacecraft radius vector and the reference body equatorial plane, measured positive north of the equatorial plane. 3) Right Ascension: The angle between the Vernal Equinox line and the projection of the reference body-spacecraft radius vector onto the Earth equatorial plane, measured eastward from the Vernal Equinox line. 4) Inertial Speed (V): The magnitude of the inertial velocity of the spacecraft. 5) Inertial Flight Path Angle (GAMMA): The angle between the spacecraft inertial velocity vector and the plane perpendicular to the reference-body-to-spacecraft (radius) vector; positive when measured away from the reference body. 6) Inertial Azimuth Angle (SIGMA): The angle, measured in the plane perpendicular to the reference-body-to-spacecraft (radius) vector, from the projection of true north into that plane eastward to the projection of the inertial velocity vector into that plane. When the reference body is taken to be the Earth, this becomes the coordinate system EME-50. (FK-4)" END_OBJECT = COORDINFO OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = RADIUS REFERENCE_OBJECT_NAME = UNK REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " Radius: Distance from the reference body to the spacecraft." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = LATITUDE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = DECLNATN REFERENCE_OBJECT_NAME = UNK REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " Declination: The angle between the reference body-spacecraft radius vector and the reference body equatorial plane, measured positive north of the equatorial plane. " END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = LONGITUDE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = "R ASCNSN" REFERENCE_OBJECT_NAME = UNK REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " Right Ascension: The angle between the Vernal Equinox line and the projection of the reference body-spacecraft radius vector onto the Earth equatorial plane, measured eastward from the Vernal Equinox line." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = VELOCITY OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = "V" REFERENCE_OBJECT_NAME = UNK REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " Inertial Speed (V): The magnitude of the inertial velocity of the spacecraft." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = VELOCITY OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = GAMMA REFERENCE_OBJECT_NAME = UNK REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " Inertial Flight Path Angle (GAMMA): The angle between the spacecraft inertial velocity vector and the plane perpendicular to the reference-body-to-spacecraft (radius) vector; positive when measured away from the reference body." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = VELOCITY OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = SIGMA REFERENCE_OBJECT_NAME = UNK REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " Inertial Azimuth Angle (SIGMA): The angle, measured in the plane perpendicular to the reference-body-to-spacecraft (radius) vector, from the projection of true north into that plane eastward to the projection of the inertial velocity vector into that plane. " END_OBJECT = VECTORD END_OBJECT = VECTOR END_OBJECT = COORDINATE /**************************************************************************** /* Inertial Spherical Coordinates - Ecliptic /**************************************************************************** OBJECT = COORDINATE COORDINATE_SYSTEM_ID = ISC_ECLP OBJECT = COORDINFO COORDINATE_SYSTEM_NAME = "ECLIPTIC INERTL SPHERCL COORDS" COORDINATE_SYSTEM_CENTER_NAME = "EARTH" COORDINATE_SYSTEM_REF_EPOCH = "UNK" /* 1950.0 */ COORDINATE_SYSTEM_DESC = " The ECLIPTIC INERTIAL SPHERICAL COORDINATE system is defined by the ecliptic plane of the Earth for the reference epoch of 1950.0. The principal direction vectors of this system are the Earth's Ecliptic Pole and the Vernal Equinox direction. The components of the coordinate system are: 1) Radius: Distance from the reference body to the spacecraft. 2) Celestial Latitude: The angle between the reference body-spacecraft radius vector and the reference body ecliptic plane, measured positive north of the ecliptic plane. 3) Celestial Longitude: The angle between the Vernal Equinox line and the projection of the reference body-spacecraft radius vector onto the Earth ecliptic plane, measured eastward from the Vernal Equinox line. 4) Inertial Speed (V): The magnitude of the inertial velocity of the spacecraft. 5) Inertial Flight Path Angle (GAMMA): The angle between the spacecraft inertial velocity vector and the plane perpendicular to the reference-body-to-spacecraft (radius) vector; positive when measured away from the reference body. 6) Inertial Azimuth Angle (SIGMA): The angle, measured in the plane perpendicular to the reference-body-to-spacecraft (radius) vector, from the projection of true north into that plane eastward to the projection of the inertial velocity vector into that plane. When the reference body is taken to be the Earth, this becomes the coordinate system ECL-50." END_OBJECT = COORDINFO OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = RADIUS REFERENCE_OBJECT_NAME = UNK REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " Radius: Distance from the reference body to the spacecraft." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = LATITUDE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = "CLST LAT" REFERENCE_OBJECT_NAME = UNK REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " Celestial Latitude: The angle between the reference body-spacecraft radius vector and the reference body ecliptic plane, measured positive north of the ecliptic plane. " END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = LONGITUDE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = "CLST LNG" REFERENCE_OBJECT_NAME = UNK REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " Celestial Longitude: The angle between the Vernal Equinox line and the projection of the reference body-spacecraft radius vector onto the ecliptic plane, measured eastward from the Vernal Equinox line." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = VELOCITY OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = "V" REFERENCE_OBJECT_NAME = UNK REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " Inertial Speed (V): The magnitude of the inertial velocity of the spacecraft." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = VELOCITY OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = GAMMA REFERENCE_OBJECT_NAME = UNK REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " Inertial Flight Path Angle (GAMMA): The angle between the spacecraft inertial velocity vector and the plane perpendicular to the reference-body-to-spacecraft (radius) vector; positive when measured away from the reference body." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = VELOCITY OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = SIGMA REFERENCE_OBJECT_NAME = UNK REFERENCE_TARGET_NAME = SPACECRAFT VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " Inertial Azimuth Angle (SIGMA): The angle, measured in the plane perpendicular to the reference-body-to-spacecraft (radius) vector, from the projection of true north into that plane eastward to the projection of the inertial velocity vector into that plane. " END_OBJECT = VECTORD END_OBJECT = VECTOR END_OBJECT = COORDINATE /**************************************************************************** /* Earth-Sun Line Cartesian Coordinates /**************************************************************************** OBJECT = COORDINATE COORDINATE_SYSTEM_ID = "ESL-CART" OBJECT = COORDINFO COORDINATE_SYSTEM_NAME = "EARTH-SUN LINE CARTES COORDS" COORDINATE_SYSTEM_CENTER_NAME = SUN COORDINATE_SYSTEM_REF_EPOCH = "N/A" COORDINATE_SYSTEM_DESC = " The Earth-Sun Line Cartesian coordinate system is defined to have the X-Y plane be the instantaneous ecliptic plane with the positive Z direction taken to be the Sun-centered, northward ecliptic normal. The positive X direction is away from the Sun along the Sun-Earth line. Y completes the righthanded set and is positive away from the Sun. Note: This system rotates with the Earth about the Sun." END_OBJECT = COORDINFO OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = ESL_X REFERENCE_OBJECT_NAME = SUN REFERENCE_TARGET_NAME = EARTH VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " The X component of the ESL coordinate system is taken to be positive in the direction away from the Sun measured along the Earth- Sun line." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = ESL_Y REFERENCE_OBJECT_NAME = SUN REFERENCE_TARGET_NAME = EARTH VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " The Y component of the ESL coordinate system is taken to be positive away from the Sun in the direction of orbital motion (dawn) and lying in the ecliptic plane. " END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = ESL_Z REFERENCE_OBJECT_NAME = SUN REFERENCE_TARGET_NAME = EARTH VECTOR_COMPONENT_UNIT = "UNK" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " The Z component of the ESL coordinate system is taken to be the Sun-centered pole of the ecliptic plane and positive in the northward direction (upward normal)." END_OBJECT = VECTORD END_OBJECT = VECTOR END_OBJECT = COORDINATE /* /**************************************************************************** /* Inertial Cartesian Coordinate System - Equatorial /**************************************************************************** OBJECT = COORDINATE COORDINATE_SYSTEM_ID = ICC_EQTL OBJECT = COORDINFO COORDINATE_SYSTEM_NAME = "EQUATORIAL INERTIAL CART COORD" COORDINATE_SYSTEM_CENTER_NAME = "UNK" COORDINATE_SYSTEM_REF_EPOCH = "UNK" /* 1950.0 */ COORDINATE_SYSTEM_DESC = " The Equatorial Inertial Cartesian Coordinate System is defined for the reference epoch of 1950.0 The X-direction is positive away from the reference body towards the Vernal Equinox which is determined by the line of intersection between the mean Earth equatorial plane and the ecliptic plane of reference. The Y direction is measured outward from the center of the reference body, perpendicular to and east of the the X-axis, and lying in the equatorial plane of reference. The Z direction is positive toward the north equatorial pole of reference, from the center of the reference body." END_OBJECT = COORDINFO OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = ICC_X REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = "N/A" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = "The X-direction is positive away from the reference body towards the Vernal Equinox which is determined by the line of intersection between the mean Earth equatorial plane and the ecliptic plane of reference." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = ICC_Y REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = "N/A" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = "The Y direction is measured outward from the center of the reference body, perpendicular to and east of the the X-axis, and lying in the equatorial plane of reference." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = ICC_Z REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = "N/A" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = "The Z direction is positive toward the north equatorial pole of reference, from the center of the reference body." END_OBJECT = VECTORD END_OBJECT = VECTOR END_OBJECT = COORDINATE /* /**************************************************************************** /* Inertial Cartesian Coordinate System - Ecliptic /**************************************************************************** OBJECT = COORDINATE COORDINATE_SYSTEM_ID = ICC_ECLP OBJECT = COORDINFO COORDINATE_SYSTEM_NAME = "ECLIPTIC INERTIAL CART COORDS" COORDINATE_SYSTEM_CENTER_NAME = "UNK" COORDINATE_SYSTEM_REF_EPOCH = "UNK" /* 1950.0 */ COORDINATE_SYSTEM_DESC = " The Equatorial Inertial Cartesian Coordinate System is defined for the reference epoch of 1950.0 The X-direction lies in the Ecliptic Plane and is positive away from the reference body towards the Vernal Equinox which is determined by the line of intersection between the mean Earth equatorial plane and the ecliptic plane of reference. The Y direction is measured outward from the center of the reference body, perpendicular to and east of the the X-axis, and lying in the ecliptic plane of reference. The Z direction is positive toward the north ecliptic pole of reference, from the center of the reference body." END_OBJECT = COORDINFO OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = ICC_X REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = "N/A" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = "The X-direction lies in the Ecliptic Plane and is positive away from the reference body towards the Vernal Equinox which is determined by the line of intersection between the mean Earth equatorial plane and the ecliptic plane of reference." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = ICC_Y REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = "N/A" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = "The Y direction is measured outward from the center of the reference body, perpendicular to and east of the the X-axis, and lying in the ecliptic plane of reference." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = ICC_Z REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = "N/A" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = "The Z direction is positive toward the north ecliptic pole of reference, from the center of the reference body." END_OBJECT = VECTORD END_OBJECT = VECTOR END_OBJECT = COORDINATE /* /**************************************************************************** /* Body-Fixed Spherical Coordinate System /**************************************************************************** /* MODIFICATIONS: /* 930223 -- MKNIFFIN /* created template OBJECT = COORDINATE COORDINATE_SYSTEM_ID = BFS_CRDS OBJECT = COORDINFO COORDINATE_SYSTEM_NAME = "BODY FIXED SPHERICAL COORDS" COORDINATE_SYSTEM_CENTER_NAME = "UNK" COORDINATE_SYSTEM_REF_EPOCH = "UNK" COORDINATE_SYSTEM_DESC = " The body-fixed spherical coordinate system is the familiar Geographic coordinate system at Earth generalized to other planets. The system consists of the components Radius, Latitude, Longitude. The definition of the prime meridian varies for each planet as does the rotation period. It is crucial to know the exact definition of these variables when changing the reference body. Note: This coordinate system rotates with the reference body." END_OBJECT = COORDINFO OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = RADIUS REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = "SPACECRAFT" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " Radius: Distance from the reference body to the spacecraft." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = LATITUDE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = PHI REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = "SPACECRAFT" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " phi = Latitude: The body-centered latitude of the spacecraft measured positive north of the reference body's equatorial plane." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = LONGITUDE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = THETA REFERENCE_OBJECT_NAME = "N/A" REFERENCE_TARGET_NAME = "SPACECRAFT" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = " theta - Longitude: the longitude of the spacecraft measured eastward from the prime meridian of the reference body to the projection of the radius vector on the equatorial plane." END_OBJECT = VECTORD END_OBJECT = VECTOR END_OBJECT = COORDINATE /* /**************************************************************************** /* Spacecraft Centered Ecliptic Coordinates /**************************************************************************** /* MODIFICATIONS: /* 930223 -- MKNIFFIN /* created template OBJECT = COORDINATE COORDINATE_SYSTEM_ID = SCC_ECLP OBJECT = COORDINFO COORDINATE_SYSTEM_NAME = "SC CENTERED ECLIPTIC COORDS" COORDINATE_SYSTEM_CENTER_NAME = "SPACECRAFT" COORDINATE_SYSTEM_REF_EPOCH = "UNK" /* 1950.0 */ COORDINATE_SYSTEM_DESC = " The Spacecraft Centered Ecliptic coordinates system (Xe, Ye, Ze) is used to describe the locations of the roll reference celestial objects (Sun or star) and the planet Venus. The coordinate system is centered at the spacecraft center of mass. The Xe-Ye plane is parallel to the Ecliptic Plane and the Ze axis points to the North Ecliptic Pole. The Xe axis points towards the Vernal Equinox. Directions in this coordinate system are described by Celestial Longitude and Celestial Latitude." END_OBJECT = COORDINFO OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = Xe REFERENCE_OBJECT_NAME = "SPACECRAFT" REFERENCE_TARGET_NAME = "N/A" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = "The Xe-direction lies in the plane parallel to the Ecliptic Plane which passes through the spacecraft center of mass. It is positive away from the spacecraft towards the Vernal Equinox which is determined by the line of intersection between the mean Earth equatorial plane and the ecliptic plane of reference." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = Ye REFERENCE_OBJECT_NAME = "SPACECRAFT" REFERENCE_TARGET_NAME = "N/A" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = "The Ye-direction is measured outward from the center of the spacecraft perpendicular to and east of the the X-axis, and lying in the plane parallel to the Ecliptic Plane which passes through the spacecraft center of mass." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = Ze REFERENCE_OBJECT_NAME = "SPACECRAFT" REFERENCE_TARGET_NAME = "N/A" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = "The Ze-direction is positive toward the North Equatorial Pole of reference, measured from the center of mass of the spacecraft." END_OBJECT = VECTORD END_OBJECT = VECTOR END_OBJECT = COORDINATE /* /**************************************************************************** /* Non-Rotating Spin Coordinates /**************************************************************************** /* MODIFICATIONS: /* 930223 -- MKNIFFIN /* created template OBJECT = COORDINATE COORDINATE_SYSTEM_ID = NRSC OBJECT = COORDINFO COORDINATE_SYSTEM_NAME = "NON-ROTATING SPIN COORDINATES" COORDINATE_SYSTEM_CENTER_NAME = "SPACECRAFT" COORDINATE_SYSTEM_REF_EPOCH = "UNK" /* 1950.0 */ COORDINATE_SYSTEM_DESC = " The roll angle of the roll reference object will be calculated in this coordinate system as well as the roll angles of the Fs, RIP, RAM, and NADIR signals. The non-rotating coordinate system (Wx, Wy, Wz) is centered at the spacecraft center of mass. The Wz-axis is parallel to the spacecraft spin axis. The Wx-Wy plane is perpendicular to the spacecraft spin axis. The Wx-Wz plane includes the Vernal Equinox of reference. Thus the Wx-axis is at the intersection of the plane perpendicular to the spacecraft spin axis and the plane containing the spin axis and the Vernal Equinox. Roll angles in this coordinate system are measured in the Wx-Wy plane from the roll reference direction." END_OBJECT = COORDINFO OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = Wx REFERENCE_OBJECT_NAME = "SPACECRAFT" REFERENCE_TARGET_NAME = "N/A" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = "The Wx-direction is positive away from the spacecraft center of mass in the direction defined by the intersection of the plane perpendicular to the spin axis and the plane containing the Vernal Equinox and the spin axis." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = Wy REFERENCE_OBJECT_NAME = "SPACECRAFT" REFERENCE_TARGET_NAME = "N/A" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = "The Wy-direction is measured outward from the center of mass of the spacecraft, perpendicular to and east of the the X-axis, and lying in the plane perpendicular to the spacecraft spin axis." END_OBJECT = VECTORD END_OBJECT = VECTOR OBJECT = VECTOR VECTOR_COMPONENT_TYPE = RANGE OBJECT = VECTORCOMP VECTOR_COMPONENT_ID = Wz REFERENCE_OBJECT_NAME = "SPACECRAFT" REFERENCE_TARGET_NAME = "N/A" VECTOR_COMPONENT_UNIT = "N/A" END_OBJECT = VECTORCOMP OBJECT = VECTORD VECTOR_COMPONENT_TYPE_DESC = "The Wz-direction is parallel to the spacecraft spin axis, measured from the spacecraft center of mass, positive in the direction of the spacecraft angular momentum." END_OBJECT = VECTORD END_OBJECT = VECTOR END_OBJECT = COORDINATE /* /*============================================================================*/ /**********Software Information Template***************************************/ /********************** PVMOV Software Information******* *********************/ /* MODIFICATIONS: */ /* Template: Software Information Template Rev: 19890121 */ /* */ /* Note: This template is completed for each node */ /* software application referenced in the PDS. */ /* */ /* Hierarchy: SOFTWARE */ OBJECT = SOFTWARE SOFTWARE_NAME = "PVMOV " NODE_ID = "PPI-UCLA" SOFTWARE_RELEASE_DATE = "N/A" SOFTWARE_TYPE = "N/A" COGNIZANT_FULL_NAME = "MURIEL KNIFFIN" SOFTWARE_ACCESSIBILITY_DESC = "Not accessible thru the PDS catalog system-Contact Node." SOFTWARE_DESC = " This program is run at the University of California, Los Angeles. It reads the EDR tape and makes a set of disk files containing the OMAG and OEFD data. It also reads the SEDR tape and makes a disk file containing the ephemeris data, the pulse time data, and the selected roll reference (SRR or SR14) data. The software is no accessible through the PDS catalog system - contact Node." END_OBJECT = SOFTWARE /******************** PVO Software Information *****************************/ /* MODIFICATIONS: /* Template: Software Information Template Rev: 19890121 */ /* */ /* Note: This template is completed for each node */ /* software application referenced in the PDS. */ /* */ /* Hierarchy: SOFTWARE */ OBJECT = SOFTWARE SOFTWARE_NAME = "PVO" NODE_ID = "PPI-UCLA" SOFTWARE_RELEASE_DATE = "N/A" SOFTWARE_TYPE = "N/A" COGNIZANT_FULL_NAME = "MURIEL KNIFFIN" SOFTWARE_ACCESSIBILITY_DESC = "Not accessible thru the PDS catalog system-Contact Node." SOFTWARE_DESC = " PVO is a C-shell script which calls a series of Fortran programs in which process the OMAG, OEFD and Ephemeris data files. It reads a set of input files created by the program PVMOV, and generates a set of output files. For the Magnetometer, the process of converting the raw sensor data to orthogonal vector components includes the following steps: 1. Remove the average of the T sensor, computed over an integral number of spin periods. The spacecraft spin period information is contained in the PVO Supplemental Experimenter Data Record. 2. Convert the sensor data to orthogonal components using a coupling matrix, whose elements are calculated, to first order, from the physical orientation of the sensors. 3. The coupling matrix and spacecraft interference parameters are adjusted by monitoring any DC amplitude and the relative phase and amplitude of the spin plane components, and any spin period modulation of the spin-aligned component. 4. The amplitude of the transverse waves in the interplanetary medium is much greater than that of compressional waves, and so the amplitude of the magnetic field remains roughly constant when the field direction changes. This behavior was used to determine the zero level of the magnetometer, which was found to be Zoff = (.13 nT - .005 nT / year) for the years 1979-1984. Approximate values and ranges of the magnetometer parameters: T sensor offset: 2.5 nT +- 1 nT Spacecraft field contribution to G sensor: 3 nT +- 1 nT G sensor offset: -10nT +- 2 nT after orbit 2205, Dec 18, 1984 P sensor offset: .13nT - .005 nT/year T and G sensors have not been functioning after orbit 3602, Oct 16, 1988. We have attempted to determine the spin plane components of the magnetic field from this data, at one hour resolution, using an observed tilt of .14 degrees of the P sensor away from the spin axis. However, this technique has possible problems such as errors from a wondering spin axis relative to the geometric axis. For the Electron Field Detector (OEFD), the data processing steps are: 1. Convert the eight bit digitized output from the Automatic Gain Controllers (range 0 to 255) to an AGC voltage (range 0 to 5V) for each channel. 2. Convert the AGC voltage to a wave amplitude in V/m/root(Hz) using preflight calibration data for each channel. 3. Convert the wave amplitude to a power (amplitude squared) if it's required. 4. Use the spacecraft orientation information to calculate the antenna phase for each channel. The phase is corrected for difference in sampling times. For the Ephemeris data the processing steps are: 1. Read in the raw ephemeris file created by PVMOV which contains the entire ephemeris data portion of the SEDR and extract the following components: (8) is the distance from the sun to the spacecraft. (11) is the celestial lat. of the spacecraft, in degrees. (12) is the celestial long. of the spacecraft, in degrees. (13) is the celestial lat. of earth. (14) is the celestial long. of earth. (32-34) are Venus-spacecraft radius vector (63-65) are the spin axis X Y Z in spacecraft centered non-rotating coordinates (92-94) are the solar position wrt Venus. (95-97) are the solar velocity wrt Venus. 2. Convert Venus-spacecraft range to altitude by subtracting 6050 and the Sun-spacecraft rage to A.U. by dividing by 149,674,000 3. Construct a VSO rotation matrix from the solar position and velocity of Venus 4. Rotate the Venus-Spacecraft and spin axis vectors into VSO coordinates" END_OBJECT = SOFTWARE /*============================================================================*/ /**********Spacecraft Instrument Template**************************************/ /* MODIFICATIONS: /* 1/21/93 MKNIFFIN /* updated changes from R. Strangeway /* 2/25/93 MKNIFFIN /* Ran on jplpds through lvtool and loader and put into /* database. Correct small errors. /* Template: Spacecraft Instrument Template Rev: 19890121 /* Note: The following templates form part of a standard /* set for the submission of a spacecraft instrument /* to the PDS. /* /* Hierarchy: SCINSTRUMENT /* INSTINFO /* INSTDETECT /* INSTELEC /* INSTFILTER /* INSTOPTICS /* SCINSTOFFSET /* INSTSECTION /* INSTSECTINFO /* INSTSECTFOVS /* INSTSECTPARM /* INSTSECTDET /* INSTSECTELEC /* INSTSECTFILT /* INSTSECTOPTC /* INSTMODEINFO /* INSTMODESECT /* INSTREFINFO /* REFERENCE /* REFAUTHORS /* OBJECT = SCINSTRUMENT SPACECRAFT_ID = PVO INSTRUMENT_ID = OEFD /* Template: Instrument Information Template Rev: 19890121 /* Note: This template shall be completed for the /* instrument id entered in the ebinstrument or /* scinstrument template. /* OBJECT = INSTINFO INSTRUMENT_NAME = "PVO PLASMA WAVE ANALYZER" INSTRUMENT_TYPE = "PLASMA WAVE" PI_PDS_USER_ID = RSTRANGEWAY NAIF_DATA_SET_ID = "N/A" BUILD_DATE = 1976 INSTRUMENT_MASS = 0.55 INSTRUMENT_HEIGHT = 0.075 INSTRUMENT_LENGTH = 0.190 INSTRUMENT_WIDTH = 0.066 INSTRUMENT_MANUFACTURER_NAME = TRW INSTRUMENT_SERIAL_NUMBER = '5971-02' INSTRUMENT_DESC = " ------------------------------------------------------ NOTE: References to figures are included in the article even though the figures aren't. This enables you to look up the actual article in the IEEE transaction and find the figures. The Pioneer Venus Orbiter Plasma Wave Investigation F.L. Scarf, W.W.L. Taylor, and P.F. Virobik IEEE Transaction on Geoscience and Remote Sensing, January 1980 ---------------------------------------------------- Abstract The Pioneer Venus plasma wave instrument has a self- contained balanced electric dipole (effective length = 0.75 m) and a 4-channel spectrum analyzer (30-percent band width filters with center frequencies at 100 Hz, 5.4 kHz, and 30 kHz). The channels are continuously active and the highest Orbiter telemetry rate (2048 bps) yields 4 spectral scans/s. The total mass of 0.55 kg includes the electronics, the antenna, and the antenna deployment mechanism. This report contains a brief description of the instrument design and a discussion of the in-flight performance. Introduction Since December 5, 1978, the electric field detector in the Pioneer Venus Orbiter has been providing measurements of wave activity in the plasma environment of Venus. The Orbiter plasma wave instrument uses a short self-contained electric dipole to detect the signals which are processed in 4 continuously active bandpass channels covering the frequency range from 100 Hz to 30 kHz. The instrument is gathering data on many aspects of the mode of interaction between the solar wind and the ionosphere (e.g., on processes that develop in the upstream solar wind region, near the bow shock and ionopause and within the ionosphere, ionosheath, and wake cavity). The instrument was also designed to collect data on whistler mode electromagnetic noise bursts from the atmosphere, and it appears that lightning from Venus is being detected by the Orbiter wave instrument. Bl preamplifier input uses a pair of 2N5556 field effect transistors specifically selected to provide matched gains and low noise levels. The input circuit was designed to have low input capacitance in order to minimize possible effects of varying antenna capacitance associated with changing plasma sheath conditions. Background The original proposal for a plasma wave instrument on the Pioneer Venus Orbiter was based on the design of the electric field detectors operating on Pioneer 8, 9 [1]. In fact, it was first proposed that an existing Pioneer 9 flight spare unit be flown, using a spacecraft element (boom or antenna) as an unbalanced electric field dipole. With this plan, the requirements on the spacecraft would have been minimal (the Pioneer 9 spare has four analog telemetry outputs, no internal commands, a mass of 0.36 kg, and total power consumption of 420 mW; the proposed antenna concept would have required some mass addition for the antenna diplexer and cabling, but no deployment mechanisms or deployment commands were required). this proposal was accepted in principle, but it turned out to be impossible to use the Pioneer 9 spare or to use a spacecraft element as an antenna. At this point it became necessary to design a new Pioneer Venus plasma wave instrument with the following constraints: a) total mass near 0.5 kg, including antenna and deployment mechanism. b) power consumption near 0.5 W; c) no commands for antenna deployment; and d) 4 analog telemetry outputs. Another significant constraint on the antenna design involved the need to provide sufficient rigidity so that the antenna would not strike the spacecraft or the solar arrays during powered flight (such as the Centaur burns near earth and the burn of the Orbit Insertion Motor at Venus). Instrument Description The constraints discussed above presented a number of serious mechanical and electronic problems and it was clear that the instrument would have to have a limited number of bandpass channels and a relatively small antenna. The science requirements of the Venus mission provided additional constraints, such as the need to cover a frequency range from below the anticipated electron cyclotron frequency up to the nominal interplanetary electron plasma frequency. the high speed of the spacecraft through the shock, ionopause, and ionosphere required the use of continuously active channels to measure rapid temporal variations without error. Finally, in order to use a body-mounted sensor on a spinning spacecraft with irregular solar arrays, it was evident that a balanced electric dipole would be needed to achieve common mode rejection of interference signals. The resulting design is shown in Fig. 1, which contains a block diagram of the electronics circuit and a drawing of the mounting of the deployed antenna on the Orbiter spacecraft. The electronics is packaged in a two-level box, as shown in Fig. 2. The dimensions of the upper part are 12.2 cm x 6.6 cm x 5.5 cm, and those of the base are 19 cm x 6.6 cm x 2 cm, with a total unit mass of 0.5 kg. The key to the overall instrument design was fundamentally related to the plan for mounting and deploying the antenna. As shown in Figs. 3 and 4, the entire 50-g antenna unit was mounted directly on the electronics box, and the individual spring- loaded antenna elements were stowed against the inside surface of the launch vehicle fairing, so that they deployed automatically as the fairing was ejected. In the deployed position the of each wire grid is 0.69 m from the point of connection to the electronics unit, and the sphere-to-sphere separation is 0.76 m. The wire grids are placed at the ends in order to provide a lumped capacitance with small collecting area. The individual wire circles have diameters of 10.5 cm, and the antenna effective length is 0.75m. The instrument antenna are mounted near the top surface of the spacecraft bus (note that the Pioneer Venus Orbiter is inverted: the top of the spacecraft and the spin axis point to southern Venus and Solar latitudes). The axis of the antenna, which bisects the two elements, is at -177.5 degrees with respect to the sun-sensor location, where positive angles are defined in the same direction as the spacecraft rotation. The effective dipole orientation is 90 degrees to this direction. Since this antenna system with small collecting area responds to induced electric fields, the transfer function for the antenna/input circuit is determined by placing the entire unit in a large parallel-plate capacitor. The capacitor is driven with a calibrated signal generator, and the preamplifier output is measured as the frequency is varied. The differential preamplifier input uses a pair of 2N5556 field effect transistors specifically selected to provide matched gains and low noise levels. The input circuit was designed to have low input capacitance in order to minimize possible effects of varying antenna capacitance associated with changing plasma sheath conditions. The four filters of the 4-channel spectrum analyzer have frequency response curves similar to those used in the 400-Hz, 22-kHz, and 30-kHz channels on Pioneer 8, 9, [1], but for the Pioneer Venus Orbiter we selected filters with 30-percent fractional bandwidth rather than the 15-percent units used previously. The automatic gain control amplifiers used here have rise times on the order of 50 ms, with decay times approximately 500 ms. Finally, the telemetry interface is straightforward. The 4 analog outputs are converted to digital form by the spacecraft and transmitted to earth in a way that depends on the selected format and on the telemetry rate. One minor frame has 512 bits, and the spacecraft transmission rates range from 4 minor frames/s down to 1 minor frame/64 s. Near periapsis the customary rates have been 2 to 4 minor frames/s during the first year in orbit. In two of the spacecraft telemetry formats (Periapsis D-the 'Optical' format, and Periapsis B-an 'Aeronomy' format) no plasma wave measurements are made. In format E ('Radar Mapping' format) only the 100-Hz channel is sampled. For the other 6 telemetry formats an entire 4-channel spectral scan is obtained with every minor frame readout. this has generally provided 2-4 scans/s near periapsis. In-Flight Performance The wave instrument has been acquiring data almost continuously since launch on May 20, 1978, and we find that the in-flight operation is remarkably free of interference associated with pickup of noise from spacecraft or experiment subsystems. The only known instrumental effect involves the detection of regular low level amplitude ripples when the spacecraft is in sunlight. This is illustrated in Fig. 5, which shows wave measurements from the region of an outbound bow shock crossing (top four panels), along with a profile of the B-field magnitude (bottom panel; data supplied by C.T. Russell). The amplitude modulation is evident only when the natural plasma wave activity is low, and this effect is a measure of the sun-oriented anisotropy of the plasma sheath surrounding the spacecraft, which is not an equipotential. The observed ripple arises because the antenna on the spinning spacecraft is at a different angular position with respect to the sun during each successive sampling. When the spacecraft is in darkness the ripple is absent, but as expected, the achievable sensitivity is not really improved. fig. 6 shows some high resolution measurements taken near periapsis in the night side. the isolated impulsive signals may well be associated with detection of lightning. It is also possible that the more continuous enhancements in the high-frequency-wave channels represent detection of ion acoustic waves associated with currents flowing near the bottom of the ionosphere. Many other examples of Orbiter plasma wave measurements are contained in a number of additional reports [2], and these papers should be consulted for more comprehensive discussions of the wave observations. Fig. 5 shows that near the shock the plasma wave instrument readily detects mid-frequency waves that we identify as ion acoustic waves (730 Hz and 5.4 kHz), and high-frequency upstream waves (30 kHz) that are thought to be electron plasma oscillations associated with superthermal electrons. The 100-Hz activity shown here probably represents electromagnetic whistler mode turbulence. Even in sunlight, the minimum detectable field strengths are close to the intrinsic threshold levels for the various channels. We find electric field spectral densities in units of (volts/meters)2/(hertz) to be about 1.2 x 10 to the -10 at 100 Hz; 1.3 x 10 to the -11 at 730 Hz, 8.8 x 10 to the -13 at 5.4 kHz, and 3 x 10 to the -13 at 30 kHz. In terms of equivalent sine waves, these in-flight thresholds are approximately 30 to 60 mu V/m. The instrument is capable of detecting signals up to 90 dB above these minimum levels before reaching saturation, but no very strong signals of this nature have ever been detected. The noise levels given above are nominal values. Actual noise levels depend on the location of the spacecraft. Noise levels are highest and most highly structured when the spacecraft is in sunlight. The noise is spin mod- ulated, with the worst noise occurring in the 100 Hz channel. Noise is reduced in the ionosphere, and in the optical shadow. In the above object no values are given for the minimum, maximum and noise levels, since these are different for each channel. The minimum and maximum signal levels can be obtained from the scaling law given in the instrument calibration section, setting V=0 for minimum and V-5 for maximum. The nominal on orbit noise levels are discussed in the instrument sensitivity section. For each channel the output Automatic Gain Controller (AGC) voltage V (range 0-5 V) is related to the input wave electric field amplitude E (in V/m/root(Hz)) through the scaling law E=a exp (bV) where: a = 5.6938 X 10^-6 b = 2.1267 at 100 Hz a = 2.1987 X 10^-6 b = 1.9676 at 730 Hz a = 6.9938 X 10^-7 b = 1.9010 at 5.4 kHz a = 2.7058 X 10^-7 b = 1.9094 at 30 kHz Acknowledgement We thank J. Atkinson and E. Vrem for their invaluable assistance with the design, fabrication, testing, and integration of the Orbiter Electric Field Detector. We are grateful to C. Hall and the staff of the Pioneer Venus Project at NASA Ames Research Center and Hughes Aircraft Company for their excellent support, and we especially acknowledge the continuing assistance of E. Tischler and W. Hightower. References [1] F.L. Scarf, G.M. Crook, I.M. Green, and P.F. Virobik, 'Initial results of the Pioneer 8 VLF electric field experiment', J. Geophys. Res., vol. 73, p. 6665, 1968 [2] F.L.Scarf, I.M. Green and G.M. Crook, 'the Pioneer 9 electric field experiment : Part 1', Cosmic Electrodynamics, vol. 1, p. 496, 1971. [3] F.L. Scarf, W.W.L. Taylor, and I.M. Green, 'Plasma waves near Venus: Initial observations', Science, vol. 203, p. 748, 1979 [4] W.W.L. Taylor, F.L. Scarf, C.T. Russell, and L.H. Brace, 'Evidence for lightning on Venus', Nature, vol. 279, p. 614, 1979 [5] W.W.L. Taylor, F.L. Scarf, C.T. Russell, and L.H. Brace, 'Absorption of whistler mode waves in the ionosphere of Venus', Science, vol. 205, p. 112, 1979." /* /********************************************************* /* SCIENTIFIC_OBJECTIVES_SUMMARY = " Since December 5, 1978, until October 7, 1992, the electric field detector in the Pioneer Venus Orbiter provided measurements of wave activity in the plasma environment of Venus. The Orbiter plasma wave instrument uses a short self-contained electric dipole to detect the signals which are processed in 4 continuously active bandpass channels covering the frequency range from 100 Hz to 30 kHz. The instrument gathered data on many aspects of the interaction between the solar wind and the ionosphere (e.g., on processes that develop in the upstream solar wind region, near the bow shock and ionopause and within the ionosphere, ionosheath, and wake cavity). The instrument was also designed to collect data on whistler mode electromagnetic noise bursts from the atmosphere, and it appears that lightning from Venus is being detected by the Orbiter wave instrument." /* /********************************************************* /* INSTRUMENT_CALIBRATION_DESC =" The antenna system has a small collecting area, and responds to induced electric fields. The transfer function for the antenna/input circuit is determined by placing the entire unit in a large parallel-plate capacitor. The capacitor is driven with a calibrated signal generator, and the preamplifier output is measured as the frequency is varied. The four filters of the 4-channel spectrum analyzer have frequency response curves similar to those used in the 400-Hz, 22-kHz, and 30-kHz channels on Pioneer 8, 9, [1], but for the Pioneer Venus Orbiter we selected filters with 30-percent fractional bandwidth rather than the 15-percent units used previously. The automatic gain control amplifiers used here have rise times on the order of 50 ms, with decay times approximately 500 ms. For each channel the output Automatic Gain Controller (AGC) voltage V (range 0-5 V) is related to the input wave electric field amplitude E (in V/m/root(Hz)) through the scaling law E=a exp (bV) where: a = 5.6938 X 10^-6 b = 2.1267 at 100 Hz a = 2.1987 X 10^-6 b = 1.9676 at 730 Hz a = 6.9938 X 10^-7 b = 1.9010 at 5.4 kHz a = 2.7058 X 10^-7 b = 1.9094 at 30 kHz " /* /********************************************************* /* OPERATIONAL_CONSID_DESC = "None provided." /* /********************************************************* /* END_OBJECT = INSTINFO /* Template: Instrument Detector Template Rev: 19890121 /* Note: This template shall be repeated for each /* detector utilized by an instrument. /* OBJECT = INSTDETECT DETECTOR_ID = "PVOEFD ANTENNA" DETECTOR_TYPE = "DIPOLE ANTENNA" DETECTOR_ASPECT_RATIO = "N/A" MINIMUM_WAVELENGTH = "N/A" MAXIMUM_WAVELENGTH = "N/A" NOMINAL_OPERATING_TEMPERATURE = 273 DETECTOR_DESC = " The entire 50-g antenna unit was mounted directly on the electronics box, and the individual spring- loaded antenna elements were stowed against the inside surface of the launch vehicle fairing, so that they deployed automatically as the fairing was ejected. In the deployed position the of each wire grid is 0.69 m from the point of connection to the electronics unit, and the sphere-to-sphere separation is 0.76 m. The wire grids are placed at the ends in order to provide a lumped capacitance with small collecting area. The individual wire circles have diameters of 10.5 cm, and the antenna effective length is 0.75m." /* /********************************************************* /* SENSITIVITY_DESC = " The Pioneer Venus plasma wave instrument has a self- contained balanced electric dipole (effective length = 0.75 m) and a 4-channel spectrum analyzer (30-percent band width filters with center frequencies at 100 Hz, 5.4 kHz, and 30 kHz). The channels are continuously active and the highest Orbiter telemetry rate (2048 bps) yields 4 spectral scans/s. Some additional characteristics of the 4-channel spectrum analyzer are worth noting. The four filters have frequency response curves similar to those used in the 400-Hz, 22-kHz, and 30-kHz channels on Pioneer 8, 9, [1], but for the Pioneer Venus Orbiter we selected filters with 30-percent fractional bandwidth rather than the 15-percent units used previously. The automatic gain control amplifiers used here have rise times on the order of 50 ms, with decay times approximately 500 ms. Even in sunlight, the minimum detectable field strengths are close to the intrinsic threshold levels for the various channels. We find electric field spectral densities in units of (volts/meters)2/(hertz) to be about 1.2 x 10 to the -10 at 100 Hz; 1.3 x 10 to the -11 at 730 Hz, 8.8 x 10 to the -13 at 5.4 kHz, and 3 x 10 to the -13 at 30 kHz. In terms of equivalent sine waves, these in-flight thresholds are approximately 30 to 60 mu V/m. The instrument is capable of detecting signals up to 90 dB above these minimum levels before reaching saturation, but no very strong signals of this nature have ever been detected. The noise levels given above are nominal values. Actual noise levels depend on the location of the spacecraft. Noise levels are highest and most highly structured when the spacecraft is in sunlight. The noise is spin mod- ulated, with the worst noise occurring in the 100 Hz channel. Noise is reduced in the ionosphere, and in the optical shadow. In the above object no values are given for the minimum, maximum and noise levels, since these are different for each channel. The minimum and maximum signal levels can be obtained from the scaling law given in the instrument calibration section, setting V=0 for minimum and V-5 for maximum. The nominal on orbit noise levels are discussed in the instrument sensitivity section." /* /********************************************************* /* END_OBJECT = INSTDETECT /* Template: Instrument Electronics Template Rev: 19890121 /* Note: This template shall be repeated for each /* electronics id description utilized by an /* instrument. /* OBJECT = INSTELEC ELECTRONICS_ID = PVOEFD ELECTRONICS_DESC = " The differential preamplifier input uses a pair of 2N5556 field effect transistors specifically selected to provide matched gains and low noise levels. The input circuit was designed to have low input capacitance in order to minimize possible effects of varying antenna capacitance associated with changing plasma sheath conditions. The four filters of the 4-channel spectrum analyzer have frequency response curves similar to those used in the 400-Hz, 22-kHz, and 30-kHz channels on Pioneer 8, 9, [1], but for the Pioneer Venus Orbiter we selected filters with 30-percent fractional bandwidth rather than the 15-percent units used previously. The automatic gain control amplifiers used here have rise times on the order of 50 ms, with decay times approximately 500 ms. For each channel the output Automatic Gain Controller (AGC) voltage V (range 0-5 V) is related to the input wave electric field amplitude E (in V/m/root(Hz)) through the scaling law E=a exp (bV) where: a = 5.6938 X 10^-6 b = 2.1267 at 100 Hz a = 2.1987 X 10^-6 b = 1.9676 at 730 Hz a = 6.9938 X 10^-7 b = 1.9010 at 5.4 kHz a = 2.7058 X 10^-7 b = 1.9094 at 30 kHz Finally, the telemetry interface is straightforward. The 4 analog outputs are converted to digital form by the spacecraft and transmitted to earth in a way that depends on the selected format and on the telemetry rate. One minor frame has 512 bits, and the spacecraft transmission rates range from 4 minor frames/s down to 1 minor frame/64 s. Near periapsis the customary rates have been 2 to 4 minor frames/s during the first year in orbit. In two of the spacecraft telemetry formats (Periapsis D-the 'Optical' format, and Periapsis B-an 'Aeronomy' format) no plasma wave measurements are made. In format E ('Radar Mapping' format) only the 100-Hz channel is sampled. For the other 6 telemetry formats an entire 4-channel spectral scan is obtained with every minor frame readout. this has generally provided 2-4 scans/s near periapsis." END_OBJECT = INSTELEC /* Template: Instrument Filter Template Rev: 19890121 /* Note: This template shall be repeated for each /* filter utilized by an instrument. /* OBJECT = INSTFILTER FILTER_NUMBER = "N/A" FILTER_NAME = "N/A" FILTER_TYPE = "N/A" MINIMUM_WAVELENGTH = "N/A" CENTER_FILTER_WAVELENGTH = "N/A" MAXIMUM_WAVELENGTH = "N/A" MEASUREMENT_WAVE_CALBRT_DESC = "N/A" END_OBJECT = INSTFILTER /* Template: Instrument Optics Template Rev: 19890121 /* Note: This template shall be completed for each /* optical instrument. /* OBJECT = INSTOPTICS TELESCOPE_ID = "N/A" TELESCOPE_FOCAL_LENGTH = "N/A" TELESCOPE_DIAMETER = "N/A" TELESCOPE_F_NUMBER = "N/A" TELESCOPE_RESOLUTION = "N/A" TELESCOPE_TRANSMITTANCE = "N/A" TELESCOPE_T_NUMBER = "N/A" TELESCOPE_T_NUMBER_ERROR = "N/A" TELESCOPE_SERIAL_NUMBER = "N/A" OPTICS_DESC = "N/A" END_OBJECT = INSTOPTICS /* Template: Spacecraft Instrument Offset Template Rev: 19890121 /* Note: This template shall be completed for each /* platform used for instrument positioning. /* OBJECT = SCINSTOFFSET PLATFORM_OR_MOUNTING_NAME = "SPACECRAFT BUS" CONE_OFFSET_ANGLE = "N/A" CROSS_CONE_OFFSET_ANGLE = "N/A" TWIST_OFFSET_ANGLE = "N/A" INSTRUMENT_MOUNTING_DESC = "The key to the overall instrument design was fundamentally related to the plan for mounting and deploying the antenna. As shown in Figs. 3 and 4, the entire 50-g antenna unit was mounted directly on the electronics box, and the individual spring- loaded antenna elements were stowed against the inside surface of the launch vehicle fairing, so that they deployed automatically as the fairing was ejected. In the deployed position the of each wire grid is 0.69 m from the point of connection to the electronics unit, and the sphere-to-sphere separation is 0.76 m. The instrument antenna are mounted near the top surface of the spacecraft bus (note that the Pioneer Venus Orbiter is inverted: the top of the spacecraft and the spin axis point to southern Venus and Solar latitudes). The axis of the antenna, which bisects the two elements, is at -177.5 degrees with respect to the sun-sensor location, where positive angles are defined in the same direction as the spacecraft rotation. The effective dipole orientation is 90 degrees to this direction." END_OBJECT = SCINSTOFFSET /* Template: Instrument Section Template Rev: 19890121 /* Note: This template group shall be repeated for each /* instrument section. /* OBJECT = INSTSECTION SECTION_ID = PVOEFD /* Template: Instrument Section Information Template Rev: 19890121 /* Note: This section shall be completed for each /* instrument section id entered in the instsection /* template. /* OBJECT = INSTSECTINFO SCAN_MODE_ID = "N/A" DATA_RATE = "N/A" SAMPLE_BITS = 8 TOTAL_FOVS = 1 /* Template: Instrument Section Fields Of View Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument section fields of view. /* OBJECT = INSTSECTFOVS FOV_SHAPE_NAME = "SINGLE-AXIS" HORIZONTAL_PIXEL_FOV = "N/A" VERTICAL_PIXEL_FOV = "N/A" HORIZONTAL_FOV = "N/A" VERTICAL_FOV = "N/A" FOVS = 1 END_OBJECT = INSTSECTFOVS END_OBJECT = INSTSECTINFO /* Template: Instrument Section Parameter Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument section parameter. /* OBJECT = INSTSECTPARM INSTRUMENT_PARAMETER_NAME = "WAVE ELECTRIC FIELD INTENSITY" MINIMUM_INSTRUMENT_PARAMETER = UNK MAXIMUM_INSTRUMENT_PARAMETER = UNK NOISE_LEVEL = UNK INSTRUMENT_PARAMETER_UNIT = "VOLT/METER" SAMPLING_PARAMETER_NAME = FREQUENCY MINIMUM_SAMPLING_PARAMETER = 0.1 MAXIMUM_SAMPLING_PARAMETER = 300 SAMPLING_PARAMETER_INTERVAL = "N/A" SAMPLING_PARAMETER_RESOLUTION = "N/A" SAMPLING_PARAMETER_UNIT = KILOHERTZ END_OBJECT = INSTSECTPARM /* In the above object no values are given for the /* minimum, maximum and noise levels, since these /* are different for each channel. The minimum /* and maximum signal levels can be obtained from /* the scaling law given in the instrument cal- /* ibration section, setting V=0 for minimum and /* V-5 for maximum. The nominal on orbit noise /* levels are discussed in the instrument sensi- /* tivity section. /* Template: Instrument Section Detector Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument section detector id. /* OBJECT = INSTSECTDET DETECTOR_ID = "PVOEFD ANTENNA" END_OBJECT = INSTSECTDET /* Template: Instrument Section Electronics Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument section electronics component. /* OBJECT = INSTSECTELEC ELECTRONICS_ID = PVOEFD END_OBJECT = INSTSECTELEC /* Template: Instrument Section Filter Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument section filter. /* OBJECT = INSTSECTFILT FILTER_NUMBER = "N/A" END_OBJECT = INSTSECTFILT /* Template: Instrument Section Optics Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument section telescope. /* OBJECT = INSTSECTOPTC TELESCOPE_ID = "N/A" END_OBJECT = INSTSECTOPTC END_OBJECT = INSTSECTION /* Template: Instrument Mode Information Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument mode. /* /*************************************************************************** OBJECT = INSTMODEINFO INSTRUMENT_MODE_ID = "SINGLE CHANNEL" GAIN_MODE_ID = AGC DATA_PATH_TYPE = "REAL TIME" INSTRUMENT_POWER_CONSUMPTION = 0.5 INSTRUMENT_MODE_DESC = "In format E (Radar Mapping format) only the 100-Hz channel is sampled." /* Template: Instrument Mode Section Information Template Rev: 19890121 /* Note: This template shall be repeated for each association of an /* instrument mode to an instrument section. /* OBJECT = INSTMODESECT SECTION_ID = PVOEFD END_OBJECT = INSTMODESECT END_OBJECT = INSTMODEINFO OBJECT = INSTMODEINFO /*************************************************************************** INSTRUMENT_MODE_ID = "MULTI-CHANNEL" GAIN_MODE_ID = AGC DATA_PATH_TYPE = "REAL TIME" INSTRUMENT_POWER_CONSUMPTION = 0.5 INSTRUMENT_MODE_DESC = "In all formats other than D, B, and E (Periapsis Optical, Aeronomy, and Radar Mapping) an entire 4-channel spectral scan is obtained with every minor frame readout. This has generally provided 2-4 scans/s near periapsis." /* Template: Instrument Mode Section Information Template Rev: 19890121 /* Note: This template shall be repeated for each association of an /* instrument mode to an instrument section. /* OBJECT = INSTMODESECT SECTION_ID = PVOEFD END_OBJECT = INSTMODESECT END_OBJECT = INSTMODEINFO /* Template: Instrument Reference Information Template Rev: 19890121 /* Note: The following template form part of a standard /* set for the submission of a publication reference /* to the PDS. /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = SCARFETAL1980 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Scarf,F.L., W.W.L. Taylor, and P.F. Virobik, 'The Pioneer Venus Orbiter Plasma Investigation',IEEE Trans. Geoscience and Remote Sensing, Jan. 1980, Volume GE-18 Number 1, pg 36." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = SCARFETAL1968 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1968 REFERENCE_DESC = " Scarf,F.L., G.M. Crook, I.M. Green, and P.F. Virobik, 'Initial results of the Pioneer 8 VLF electric field experiment', J. Geophys. Res., vol. 73, p. 6665, 1968." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = SCARFETAL1971 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "COSMIC ELECTRODYNAMICS" PUBLICATION_DATE = 1971 REFERENCE_DESC = " Scarf,F.L., I.M. Green and G.M. Crook, 'the Pioneer 9 electric field experiment : Part 1', Cosmic Electrodynamics, vol. 1, p. 496, 1971." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = SCARFETAL1979B OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = SCIENCE PUBLICATION_DATE = 1979 REFERENCE_DESC = " Scarf,F.L., W.W.L. Taylor, and I.M. Green, 'Plasma waves near Venus: Initial observations', Science, vol. 203, p. 748, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = TAYLORETAL1979A OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "VENUS LIGHTNING" JOURNAL_NAME = NATURE PUBLICATION_DATE = 1979 REFERENCE_DESC = " Taylor,W.W.L., F.L. Scarf, C.T. Russell, and L.H. Brace, 'Evidence for lightning on Venus', Nature, vol. 279, p. 614, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "W.W. TAYLOR" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = TAYLORETAL1979B OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = SCIENCE PUBLICATION_DATE = 1979 REFERENCE_DESC = " Taylor,W.W.L, F.L. Scarf, C.T. Russell, and L.H. Brace, 'Absorption of whistler mode waves in the ionosphere of Venus', Science, vol. 205, p. 112, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "W.W. TAYLOR" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO END_OBJECT = SCINSTRUMENT /*============================================================================*/ /*********Spacecraft Data Set Template******************Rev: 19890121******** */ /* MODIFICATIONS: */ /* 930309: MKNFFIN - created template */ /* Note: The following templates form part of a standard set */ /* for the submission of a single dataset to the PDS. */ /* Hierarchy: SCDATASET */ /* DATASETINFO */ /* DATASETTARG */ /* DSPARMINFO */ /* SCDSHOST */ /* DSREFINFO */ /* REFERENCE */ /* REFAUTHORS */ OBJECT = SCDATASET DATA_SET_ID = "PVO-V-OEFD-4--EFIELD-24SEC-V1.0" OBJECT = DATASETINFO DATA_SET_NAME = "PVO VENUS EFD RESAMP BROWSE ELECTRIC FIELD 24SEC AVGS V1.0" DATA_SET_COLLECTION_MEMBER_FLG = N START_TIME = 1978-12-05T07:20:07.282 STOP_TIME = 1992-10-08T16:30:23.299 NATIVE_START_TIME = UNK NATIVE_STOP_TIME = UNK DATA_OBJECT_TYPE = "TIME SERIES" DATA_SET_RELEASE_DATE = 1993-09-01 PROCESSING_LEVEL_ID = 4 PRODUCER_FULL_NAME = "MURIEL KNIFFIN" PRODUCER_INSTITUTION_NAME = UCLA SOFTWARE_FLAG = Y DETAILED_CATALOG_FLAG = N PROCESSING_START_TIME = 1991-11-06 PROCESSING_STOP_TIME = UNK DATA_SET_DESC = " This data set contains wave electric field amplitudes measured at four different frequencies by the Pioneer Venus Orbiter Electric Field Detector. The data are averaged over 2 spin periods (approximately 24 seconds. The averaging intervals are overlapped and data are output on single spin period centers, the time stamp corresponding to the center of the averaging window. This results in an unevenly sampled dataset as the spin period varies. The amplitude of the ''flutter'' in the averaging window size is generally less than 0.004 seconds in the 12 second period of an orbit. Orbits that have spin period adjustment thruster firings will have larger variations in the output time steps, but such adjustments are seldom, if ever, done in the hour surrounding periapsis. Each averaging interval contains both the minimum amplitude, average amplitude and peak amplitude for that interval at each of the four frequencies. The four frequencies are 100 Hz, 730 Hz, 5.4 kHz, 30 kHz. The frequency filters are narrow-band, with a 30% bandwidth. Thus wave amplitudes are given in V/m/root(Hz). The filters are continuously active, but data are only provided at a rate determined by the spacecraft telemetry rate. The wave antenna is oriented perpendicular to the spacecraft spin axis, and so the wave instrument measures only wave fields in the spacecraft spin plane. The wave antenna is a small Y-shaped structure, with effective separation of 0.76 meters. Other datasets on the CD-ROM are the Ephemeris which contains spacecraft position in Venus Solar Orbital coordinates, spacecraft altitude, solar zenith angle, Venus centered longitude and latitude, spacecraft spin axis components, celestial longitude and latitude of the spacecraft, celestial longitude of the earth, and the Sun-spacecraft range. Other ancillary datasets are the: 1) phase and offset which contains the phase amplitude of sun synchronous modulation of the 4 signals (E100, E730, E5.4 and E30K), and offsets of the G sensor. 2) The engineering dataset which contains temperatures, magnetometer modes, magnetometer sample format, magnetometer spin average select, telemetry data format, telemetry bit rate, spacecraft spin period, pulse time, the difference between the Sun pulse time and the Rip pulse time, and the pulse time flag. 3) The instrument status dataset which contains amplitudes of spin ripple, differences between amplitudes, ratio of the amplitudes, phase differences between pseudosensors, average field seen by the pseudosensors, cosine amplitude, and sine amplitude." CONFIDENCE_LEVEL_NOTE = " The instrument noise level (and hence sensitivity) is determined by the ambient environment at the time of observation. Photo- electrons emitted from various spacecraft surfaces appear to be a strong source of electric field interference. As a consequence data acquired when the spacecraft is in sunlight often are contaminated by spin modulated interference, especially when the spacecraft is in the low density solar wind, where the Debye length is several meters. The noise is usually lowest when the antenna elements are in the spacecraft shadow. The noise level is also reduced when the spacecraft is deep within the dayside ionosphere, where the Debye length is much smaller than the antenna size. The noise is not present when the spacecraft is within the optical shadow of the planet. In this case, however, additional noise features are observed (mainly at 100 Hz) when the spacecraft is at low altitude within the nightside ionosphere. This interference is readily discriminated in the high resolution data, where the noise is present as a sharp pulse occurring twice per spin. The averaging scheme used can be subject to temporal aliasing when the data rate is sufficiently low, such that only one or two data are obtained per 24 second interval. Since the sampling interval and spin period are not exactly synchronized, periodic noise signals, such as the interference, are aliased by the low sampling frequency. In this case the data display periodic structure, but with a period much longer than the spin period. The instrument was calibrated in air. No attempt to incorporate changes in antenna-plasma coupling due to changes in Debye length have been included in the data processing." END_OBJECT = DATASETINFO OBJECT = DATASETTARG TARGET_NAME = VENUS END_OBJECT = DATASETTARG OBJECT = DSPARMINFO SAMPLING_PARAMETER_NAME = TIME SAMPLING_PARAMETER_RESOLUTION = 24.0 MINIMUM_SAMPLING_PARAMETER = "N/A" MAXIMUM_SAMPLING_PARAMETER = "N/A" SAMPLING_PARAMETER_INTERVAL = 12.0 MINIMUM_AVAILABLE_SAMPLING_INT = .125 SAMPLING_PARAMETER_UNIT = AMPLITUDE DATA_SET_PARAMETER_NAME = "WAVE ELECTRIC FIELD AMPLITUDE" NOISE_LEVEL = "N/A" DATA_SET_PARAMETER_UNIT = "VOLTS/METER/HERTZ**.5" END_OBJECT = DSPARMINFO OBJECT = SCDSHOST INSTRUMENT_HOST_ID = PVO INSTRUMENT_ID = OEFD END_OBJECT = SCDSHOST OBJECT = DSREFINFO REFERENCE_KEY_ID = SCARFETAL1979B OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = SCIENCE PUBLICATION_DATE = 1979 REFERENCE_DESC = " Scarf,F.L., W.W.L. Taylor, and I.M. Green, 'Plasma waves near Venus: Initial observations', Science, vol. 203, p. 748, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK. L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = TAYLORETAL1979A OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "VENUS LIGHTNING" JOURNAL_NAME = NATURE PUBLICATION_DATE = 1979 REFERENCE_DESC = " Taylor,W.W.L., F.L. Scarf, C.T. Russell, and L.H. Brace, 'Evidence for lightning on Venus', Nature, vol. 279, p. 614, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "W.W. TAYLOR" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = TAYLORETAL1979B OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = SCIENCE PUBLICATION_DATE = 1979 REFERENCE_DESC = " Taylor,W.W.L, F.L. Scarf, C.T. Russell, and L.H. Brace, 'Absorption of whistler mode waves in the ionosphere of Venus', Science, vol. 205, p. 112, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "W.W. TAYLOR" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = SCARFETAL1980A OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Scarf,F.L., W.W.L. Taylor, and P.F. Virobik, 'The Pioneer Venus Orbiter Plasma Investigation',IEEE Trans. Geoscience and Remote Sensing, Jan. 1980, Volume GE-18 Number 1, pg 36." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO OBJECT = DSREFINFO REFERENCE_KEY_ID = SCARFETAL1980B OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "VENUS LIGHTNING" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Scarf,F.L., W.W.L. Taylor, and C.T. Russell, and L.H. Brace, 'Lightning on Venus: Orbiter detection of whistler signals, J. Geophys. Res.,vol 85, p. 8158, 1980." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK. L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO OBJECT = DSREFINFO REFERENCE_KEY_ID = SCARFETAL1980C OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Scarf,F.L., W.W.L. Taylor, and C.T. Russell, and R.C. Elphic, 'Pioneer Venus plasma wave observations: The solar wind - Venus interaction', J. Geophys. Res., vol. 85, p. 7599, 1980." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK. L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO OBJECT = DSREFINFO REFERENCE_KEY_ID = SCARFETAL1983 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "VENUS LIGHTNING" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1983 REFERENCE_DESC = " Scarf,F.L., and C.T. Russell, 'Lightning measurements from the Pioneer Venus orbiter, Geophys. Res. Lett., vol.10, p.1192, 1983." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO OBJECT = DSREFINFO REFERENCE_KEY_ID = RUSSELL1991 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "SPACE SCIENCE REVIEW" PUBLICATION_DATE = 1991 REFERENCE_DESC = " C.T. Russell, 'Venus Lightning', Space Science Review, vol. 55, p. 317, 1991." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO OBJECT = DSREFINFO REFERENCE_KEY_ID = STRANGEWAY1991 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "SPACE SCIENCE REVIEW" PUBLICATION_DATE = 1991 REFERENCE_DESC = " R.J. Strangeway, 'Plasma waves at Venus', Space Science Review, vol. 55, p.317, 1991." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "ROBERT J. STRANGEWAY" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO END_OBJECT = SCDATASET /*============================================================================*/ /**********Spacecraft Data Set Template*************************Rev: 19890121 */ /* MODIFICATIONS: */ /* 930309: MKNIFFIN - created template i */ /* 930310: MKNIFFIN - updated template with info from RS. */ /* ran thru jpl loader - ok. */ /* 930316: MKNIFFIN - updated with ref from RJS. Ran thru jpl loader */ /* ok. */ /* Note: The following templates form part of a standard set */ /* for the submission of a single dataset to the PDS. */ /* Hierarchy: SCDATASET */ /* DATASETINFO */ /* DATASETTARG */ /* DSPARMINFO */ /* SCDSHOST */ /* DSREFINFO */ /* REFERENCE */ /* REFAUTHORS */ OBJECT = SCDATASET DATA_SET_ID = "PVO-V-OEFD-3--EFIELD-HIRES-V1.0" OBJECT = DATASETINFO DATA_SET_NAME = "PVO VENUS EFD CALIBRATED ELECTRIC FIELD HIGH RES. V1.0" DATA_SET_COLLECTION_MEMBER_FLG = N START_TIME = 1978-12-05T07:20:07.282 STOP_TIME = 1992-10-08T16:30:37.204 NATIVE_START_TIME = UNK NATIVE_STOP_TIME = UNK DATA_OBJECT_TYPE = "TIME SERIES" DATA_SET_RELEASE_DATE = 1993-09-01 PROCESSING_LEVEL_ID = 4 PRODUCER_FULL_NAME = "MURIEL KNIFFIN" PRODUCER_INSTITUTION_NAME = UCLA SOFTWARE_FLAG = Y DETAILED_CATALOG_FLAG = N PROCESSING_START_TIME = 1991-11-06 PROCESSING_STOP_TIME = 1993-03-30 DATA_SET_DESC = " This data set contains wave electric field amplitudes measured at four different frequencies by the Pioneer Venus Orbiter Electric Field Detector. The four frequencies are 100 Hz, 730 Hz, 5.4 kHz, 30 kHz. The frequency filters are narrow-band, with a 30% bandwidth. Thus wave intensities are given in V2/m2/Hz. The filters are continuously active, but data are only provided at a rate determined by the spacecraft telemetry rate. The wave antenna is oriented perpendicular to the spacecraft spin axis, and so the wave instrument measures only wave fields in the spacecraft spin plane. Spin modulation of naturally occurring signals can be used to obtain two dimensional wave field information. The wave antenna is a small Y-shaped structure, with effective separation of 0.76 meters. The spin phase of the effective dipole is included within the high resolution data set for each of the channels, which are sampled at different times. Other datasets on the CD-ROM are the Ephemeris which contains spacecraft position in Venus Solar Orbital coordinates, spacecraft altitude, solar zenith angle, Venus centered longitude and latitude, spacecraft spin axis components, celestial longitude and latitude of the spacecraft, celestial longitude of the earth, and the Sun-spacecraft range. Other ancillary datasets are the: 1) phase and offset which contains the phase amplitude of sun synchronous modulation of the 4 signals (E100, E730, E5.4 and E30K), and offsets of the G sensor. 2) The engineering dataset which contains temperatures, magnetometer modes, magnetometer sample format, magnetometer spin average select, telemetry data format, telemetry bit rate, spacecraft spin period, pulse time, the difference between the Sun pulse time and the Rip pulse time, and the pulse time flag. 3) The instrument status dataset which contains amplitudes of spin ripple, differences between amplitudes, ratio of the amplitudes, phase differences between pseudosensors, average field seen by the pseudosensors, cosine amplitude, and sine amplitude." CONFIDENCE_LEVEL_NOTE = " The instrument noise level (and hence sensitivity) is determined by the ambient environment at the time of observation. Photo- electrons emitted from various spacecraft surfaces appear to be a strong source of electric field interference. As a consequence data acquired when the spacecraft is in sunlight often are contaminated by spin modulated interference, especially when the spacecraft is in the low density solar wind, where the Debye length is several meters. The noise is usually lowest when the antenna elements are in the spacecraft shadow. The noise level is also reduced when the spacecraft is deep within the dayside ionosphere, where the Debye length is much smaller than the antenna size. The noise is not present when the spacecraft is within the optical shadow of the planet. In this case, however, additional noise features are observed (mainly at 100 Hz) when the spacecraft is at low altitude within the nightside ionosphere. This interference is readily discriminated in the high resolution data, where the noise is present as a sharp pulse occurring twice per spin. " END_OBJECT = DATASETINFO OBJECT = DATASETTARG TARGET_NAME = VENUS END_OBJECT = DATASETTARG OBJECT = DSPARMINFO SAMPLING_PARAMETER_NAME = TIME SAMPLING_PARAMETER_RESOLUTION = "N/A" MINIMUM_SAMPLING_PARAMETER = "N/A" MAXIMUM_SAMPLING_PARAMETER = "N/A" SAMPLING_PARAMETER_INTERVAL = "N/A" MINIMUM_AVAILABLE_SAMPLING_INT = 0.125 SAMPLING_PARAMETER_UNIT = INTENSITY DATA_SET_PARAMETER_NAME = "WAVE ELECTRIC FIELD INTENSITY" NOISE_LEVEL = "N/A" DATA_SET_PARAMETER_UNIT = "(VOLTS/METER)**2/HERTZ" END_OBJECT = DSPARMINFO OBJECT = DSPARMINFO SAMPLING_PARAMETER_NAME = TIME SAMPLING_PARAMETER_RESOLUTION = "N/A" MINIMUM_SAMPLING_PARAMETER = "N/A" MAXIMUM_SAMPLING_PARAMETER = "N/A" SAMPLING_PARAMETER_INTERVAL = "N/A" MINIMUM_AVAILABLE_SAMPLING_INT = 0.125 SAMPLING_PARAMETER_UNIT = PHASE DATA_SET_PARAMETER_NAME = "WAVE ELECTRIC FIELD PHASE" NOISE_LEVEL = "UNK" DATA_SET_PARAMETER_UNIT = DEGREES END_OBJECT = DSPARMINFO OBJECT = SCDSHOST INSTRUMENT_HOST_ID = PVO INSTRUMENT_ID = OEFD END_OBJECT = SCDSHOST OBJECT = DSREFINFO REFERENCE_KEY_ID = SCARFETAL1979B OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = SCIENCE PUBLICATION_DATE = 1979 REFERENCE_DESC = " Scarf,F.L., W.W.L. Taylor, and I.M. Green, 'Plasma waves near Venus: Initial observations', Science, vol. 203, p. 748, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK. L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = TAYLORETAL1979A OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "VENUS LIGHTNING" JOURNAL_NAME = NATURE PUBLICATION_DATE = 1979 REFERENCE_DESC = " Taylor,W.W.L., F.L. Scarf, C.T. Russell, and L.H. Brace, 'Evidence for lightning on Venus', Nature, vol. 279, p. 614, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "W.W. TAYLOR" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = TAYLORETAL1979B OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = SCIENCE PUBLICATION_DATE = 1979 REFERENCE_DESC = " Taylor,W.W.L, F.L. Scarf, C.T. Russell, and L.H. Brace, 'Absorption of whistler mode waves in the ionosphere of Venus', Science, vol. 205, p. 112, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "W.W. TAYLOR" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = SCARFETAL1980A OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Scarf,F.L., W.W.L. Taylor, and P.F. Virobik, 'The Pioneer Venus Orbiter Plasma Investigation',IEEE Trans. Geoscience and Remote Sensing, Jan. 1980, Volume GE-18 Number 1, pg 36." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO OBJECT = DSREFINFO REFERENCE_KEY_ID = SCARFETAL1980B OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "VENUS LIGHTNING" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Scarf,F.L., W.W.L. Taylor, and C.T. Russell, and L.H. Brace, 'Lightning on Venus: Orbiter detection of whistler signals, J. Geophys. Res.,vol 85, p. 8158, 1980." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK. L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO OBJECT = DSREFINFO REFERENCE_KEY_ID = SCARFETAL1980C OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Scarf,F.L., W.W.L. Taylor, and C.T. Russell, and R.C. Elphic, 'Pioneer Venus plasma wave observations: The solar wind - Venus interaction', J. Geophys. Res., vol. 85, p. 7599, 1980." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK. L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO OBJECT = DSREFINFO REFERENCE_KEY_ID = SCARFETAL1983 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "VENUS LIGHTNING" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1983 REFERENCE_DESC = " Scarf,F.L., and C.T. Russell, 'Lightning measurements from the Pioneer Venus orbiter, Geophys. Res. Lett., vol.10, p.1192, 1983." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DR. FREDERICK L. SCARF" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO OBJECT = DSREFINFO REFERENCE_KEY_ID = RUSSELL1991 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "SPACE SCIENCE REVIEW" PUBLICATION_DATE = 1991 REFERENCE_DESC = " C.T. Russell, 'Venus Lightning', Space Science Review, vol. 55, p. 317, 1991." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO OBJECT = DSREFINFO REFERENCE_KEY_ID = STRANGEWAY1991 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "SPACE SCIENCE REVIEW" PUBLICATION_DATE = 1991 REFERENCE_DESC = " R.J. Strangeway, 'Plasma waves at Venus', Space Science Review, vol. 55, p.317, 1991." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "ROBERT J. STRANGEWAY" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO END_OBJECT = SCDATASET /*============================================================================*/ /**********Data Set Processing Template****************************************/ /* MODIFICATIONS */ /* Last changes made */ /* Template: Data Set Processing Template Rev: 19890121 */ /* */ /* Note: This template shall be repeated for each */ /* source dataset id used in production of the */ /* dataset id in the dataset template. */ /* */ /* Hierarchy: DSPROCESSING */ OBJECT = DSPROCESSING SOURCE_DATA_SET_ID = "N/A" SOFTWARE_NAME = "PVMOV" PRODUCT_DATA_SET_ID = "PVO-V-OMAG/OEFD/OPA-1-EDR---V1.0" END_OBJECT = DSPROCESSING /**********Data Set Processing Template****************************************/ /* Template: Data Set Processing Template Rev: 19890121 */ /* */ /* Note: This template shall be repeated for each */ /* source dataset id used in production of the */ /* dataset id in the dataset template. */ /* */ /* Hierarchy: DSPROCESSING */ OBJECT = DSPROCESSING SOURCE_DATA_SET_ID = "N/A" SOFTWARE_NAME = "PVO" PRODUCT_DATA_SET_ID ="PVO-V-OEFD-4--EFIELD-24SEC-V1.0" END_OBJECT = DSPROCESSING /******************************************************************************/ /* Template: Data Set Processing Template Rev: 19890121 */ /* */ /* Note: This template shall be repeated for each */ /* source dataset id used in production of the */ /* dataset id in the dataset template. */ /* */ /* Hierarchy: DSPROCESSING */ OBJECT = DSPROCESSING SOURCE_DATA_SET_ID = "N/A" SOFTWARE_NAME = "PVO" PRODUCT_DATA_SET_ID = "PVO-V-OEFD-3--EFIELD-HIRES-V1.0" END_OBJECT = DSPROCESSING /*============================================================================*/ /*********Parameter Template***************************************************/ /******** Plasma Wave Spectrum Parameter **************************************/ /* MODIFICATIONS: /* Created by SJOY /* 930316 updated by MKNIFFIN with RSTRANGEWAY comments */ /* Template: Parameter Template Rev: 19890121 */ /* */ /* Note: This template shall be completed for each combination */ /* of data set parameter name, instrument parameter */ /* name and instrument host id associated with a dataset. */ /* */ /* Hierarchy: PARAMETER */ OBJECT = PARAMETER INSTRUMENT_HOST_ID ='PVO' DATA_SET_PARAMETER_NAME ='PLASMA WAVE SPECTRUM' INSTRUMENT_PARAMETER_NAME ='WAVE ELECTRIC FIELD AMPLITUDE' IMPORTANT_INSTRUMENT_PARMS = 1 END_OBJECT = PARAMETER /* /******* Plasma Wave Spectrum Parameter Description ***************************/ /* MODIFICATIONS: /* Template: Data Set Instrument Parameter Description Template Rev: 19890121 */ /* */ /* Note: This template shall be completed for any */ /* data set or instrument parameter description. */ /* */ /* Hierarchy: DSINSTPARMD */ OBJECT = DSINSTPARMD DATA_SET_OR_INSTRUMENT_PARM_NM= 'PLASMA WAVE AMPLITUDE SPECTRUM' DATA_SET_OR_INST_PARM_DESC = " A set of derived parameters consisting of wave electric field amplitudes at various frequencies over a range of frequencies. The MKS units are: Volts/Meter/Hertz**.5 (the square root of plasma wave spectrum)" END_OBJECT = DSINSTPARMD /* /************ Wave Electrical Field Amplitude Parameter Description ***********/ /* MODIFICATIONS: /* Template: Data Set Instrument Parameter Description Template Rev: 19890121 */ /* */ /* Note: This template shall be completed for any */ /* data set or instrument parameter description. */ /* */ /* Hierarchy: DSINSTPARMD */ OBJECT = DSINSTPARMD DATA_SET_OR_INSTRUMENT_PARM_NM= "WAVE ELECTRIC FIELD AMPLITUDE" DATA_SET_OR_INST_PARM_DESC = " A measured parameter equaling the electric field amplitude in a specific frequency passband (in MKS unit: VOLTS/METER) measured in a single sensor or antenna." END_OBJECT = DSINSTPARMD /*============================================================================*/ /***********Spacecraft Instrument Template*************************************/ /* MODIFICATIONS /* /* Template: Spacecraft Instrument Template Rev: 19890121 /* Note: The following templates form part of a standard /* set for the submission of a spacecraft instrument /* to the PDS. /* /* Hierarchy: SCINSTRUMENT /* INSTINFO /* INSTDETECT /* INSTELEC /* INSTFILTER /* INSTOPTICS /* SCINSTOFFSET /* INSTSECTION /* INSTSECTINFO /* INSTSECTFOVS /* INSTSECTPARM /* INSTSECTDET /* INSTSECTELEC /* INSTSECTFILT /* INSTSECTOPTC /* INSTMODEINFO /* INSTMODESECT /* INSTREFINFO /* REFERENCE /* REFAUTHORS /* OBJECT = SCINSTRUMENT SPACECRAFT_ID = PVO INSTRUMENT_ID = OMAG /* Template: Instrument Information Template Rev: 19890121 /* Note: This template shall be completed for the /* instrument id entered in the ebinstrument or /* scinstrument template. /* OBJECT = INSTINFO INSTRUMENT_NAME = "FLUXGATE MAGNETOMETER" INSTRUMENT_TYPE = MAGNETOMETER PI_PDS_USER_ID = CTRUSSELL NAIF_DATA_SET_ID = "N/A" BUILD_DATE = 1976 INSTRUMENT_MASS = 1.98 INSTRUMENT_HEIGHT = .15 INSTRUMENT_LENGTH = .22 INSTRUMENT_WIDTH = .15 INSTRUMENT_MANUFACTURER_NAME = "WESTINGHOUSE ELECTRIC" INSTRUMENT_SERIAL_NUMBER = "59-6803" /* 5968A03, 5968B03 */ INSTRUMENT_DESC = " ---------------------------------------------------------- Pioneer Venus Orbiter Fluxgate Magnetometer C.T. Russell, R.C. Snare, J.D. Means, and R.C. Elphic IEEE Transactions on Geoscience and Remote Sensing, January 1980. ---------------------------------------------------------- Abstract The Earth's atmosphere is shielded from the solar wind, the rapidly expanding ionized gas of the sun's outer corona, by a moderately strong magnetic field generated by a dynamo inside the liquid core of the earth. That Venus is not thus shielded was evident from the measurements of the earliest probes to Venus [1], [2]. It was not certain that these measurements indicated that Venus had no intrinsic field. Rather, the existence of a small intrinsic field was still possible [3], and in fact expected from dynamo models [4]. A measure of the size of any Venus moment would be a check on our understanding of planetary dynamos. Furthermore, the solar wind was thought to interact directly with the upper atmosphere of Venus, a situation quite unlike that probed on other planetary missions. (Mars may have a similar interaction with the solar wind, but Martian studies have concentrated on the surface and lower atmosphere rather than the upper atmosphere.) Such an interaction is only poorly understood. It is possible that the weak magnetic field of the solar wind could act to shield the upper atmosphere by inhibiting the solar wind penetration into the atmosphere. Thus it was important for both aeronomical and planetological reasons to measure the magnetic field in the near vicinity of Venus. Only from an orbiter with a controllable periapsis altitude could the requisite series of low-altitude measurements be made. The intent of the Pioneer Venus mission was to be both comprehensive and low cost. The former requirement led to the inclusion of a large number of instruments and the need for a moderately high data rate and hence a despun antenna. The latter requirement led to a spinning spacecraft, a minimum magnetic cleanliness program and no allowance for redundancy. Even with a despun antenna the Pioneer Venus spacecraft would sometimes have to transmit data at rates as low as 8 bits/s when Venus was on the far side of the sun and the deep space net telemetry stations were being used for outer planet missions. These constraints made for some exacting design challenges both for the spacecraft design team and the magnetometer team. System Design Since the spacecraft designers were attempting to maximize the use of off-the-shelf hardware from programs without a need for magnetic cleanliness, the decision was made earlier in the program to place the sensors as far away from the center of the spacecraft as possible (approx. 5 m). Since there would be moderately high thrust at orbit injection and interplanetary measurements and deployment of the magnetometer were needed before orbit injection, the boom for the magnetometer was made rigid. This rigid boom was stowed in three hinged sections on top of the spacecraft and deployed by centrifugal force shortly after launch and interplanetary insertion. A magnetic field is a vector quantity which can be specified by a magnitude and two angles or the three orthogonal components of the vector. At any instant of time this measurement requires three orthogonal detectors. On a spinning spacecraft, if the external field remains steady and the spacecraft field and internal instrument zero levels are accurately known, a single sensor tilted with respect to the spin axis will suffice. There will be a sine wave whose amplitude and phase, relative to some direction in space such as the sun, give the two components of the field in the spin plane. The average over a spin period gives a measure of the field along the spin axis. Although conditions of sufficiently steady field are frequent in the vicinity of Venus, the interesting regions are where the field values change rapidly. Thus three sensors were deemed necessary. The despun antenna assembly was expected to be magnetic as were several other subsystems. Furthermore, it was possible that these fields might change during the mission. Monitoring the field at two radial distances would help monitor such changes through the differences between the two readings if the sensors gains and zero levels remained constant. While this feature was desirable it was not affordable within the weight and power allowance of the magnetic fields investigation. A compromise design was to take one of the sensors from the triad on the end of the boom and install it 1/3 of the way back along the boom tilted with respect to the satellite spin axis and at right angles to the sensor in the spin plane. At low frequencies, well below the spacecraft spin frequency, this provided two measures of the field at varying distances from the spacecraft subject to the limitations discussed above. At high frequencies, at which interference was expected to be minimal, the readings could be combined to give the equivalent readings of three mutually orthogonal sensors. Not only did this approach provide a rudimentary gradiometer, but also reassuring redundancy. Only the failure of two sensors would have prevented the measurements of three components of the magnetic field. No single sensor failure would have jeopardized the measurement. Our next design challenge was the problem of the occasional very low telemetry rates. At 8 b/s, we would obtain only one vector sample of the magnetic field every 21 or 64 s depending on which telemetry format was being used. Since the spin period of the spacecraft was 12 s these low data rates were insufficient to enable the amplitude and phase of the signal from the sensors with components in the spin plane to be determined. Thus it was necessary to 'despin' the measurements to an inertial frame before transmittal. The optimum despinning routine would be to multiply the data by sine and cosine waves in phase with the rotation and average over an integral number of spin periods. Again weight and power were not available for the optimum approach and we used a Walsh transform rather than a Fourier transform. The Walsh transform is basically the multiplication of the data by two square waves in quadrature at the spin period. Overlapped averages are accumulated in six averaging registers, half of which were read out one telemetry cycle and the other half the next. There are 64 samples in each average which could be spread over 1, 2, or 4 spins, resulting in overlapped samples being returned every 1/2, 1, or 2 spins or every 6, 12, or 24 s. Thus at the lowest bit rate, 8 b/s, when the telemetry format is returning a vector every 21 s, accurate vector measurements are obtained. As mentioned above, well below the spin frequency one can determine the two components of the field in the spin plane from one sensor with a component in the spin plane. Thus in normal operation at low bit rates (called NORMAL MODE) the instrument performs a Walsh transform on only the outboard sensor in the spin plane (called the T sensor). The in phase average of T and quadrature average of T are stored along with the usual average of the readings from the outboard sensor parallel to the spin axis (the P sensor). This scheme provides only a measure of the field at the outboard sensor. Another operating mode (Gradiometer mode) was included to provide in-phase and quadrature transforms and a regular average of the inboard G sensor. In the Gradiometer mode all rates remain the same. The only difference is that the G sensor averages are stored in the second set of three averaging registers at the expense of overlapped averages. To obtain both the desired range (+/- 128 nT) and resolution (+/- 1/16 nT), a 12-bit analog-to-digital conversion was used. To optimize the utilization of the available telemetry, 32 bits per vector sample, two of the 12-bit samples were converted to floating point words consisting of an eight-bit mantissa and a two-bit exponent by checking the leading bit for zeros and shifting bits if the leading bit was zero. A maximum of three shifts was permitted. The number of shifts formed the exponent. Thus these two measurements had resolution of +/- 1/2 nT when the reading was greater than 64 gamma in magnitude changing to +/- 1/16 nT when the reading was less than 16 nT. It is necessary to limit the bandwidth of the magnetometer so that signals of frequency too high to be resolved by the telemetry system, do not enter the sampling circuitry. The maximum frequency that can be properly analyzed is half the sampling frequency and is called the Nyquist frequency. If signals enter the telemetry stream at frequencies above the Nyquist frequency they appear to occur at a frequency below their true frequency. This process is called aliasing and the filters in the instrument that prevent this are called aliasing filters, although a more proper name would be nonaliasing filters. Since the telemetry rate of the spacecraft varied over an enormous range, the corner frequency of the aliasing filters too had to vary. These corner frequencies were controlled automatically according to the instrument sample rate. Depending on the telemetry format the instrument could sample once per minor frame (512 bits) or three times. These modes were called SLOW sampling and FAST sampling, respectively. At telemetry rates of 512 b/s and below the corner frequency was kept fixed at 0.2 Hz. The resultant sample rates and 3 dB points are given in Table 1. When the sample rate drops below 0.5 Hz, onboard averaging is generally used. Table 1 --------------------------------------------------------- Pioneer Venus Orbiter Sample Rates and Corner Frequencies --------------------------------------------------------- Spacecraft Slow Sample Mode Fast Sample Mode Telemetry Sample Corner Sample Corner Rate (bps) Rate(Hz) Freq.(Hz) Rate(Hz) Freq.(Hz) --------------------------------------------------------- 2048 4 1.8 12 4.5 1024 2 0.4 6 3.0 683 1.33 0.2 4 2.5 512 1 0.2 3 0.2 341 0.67 0.2 2 0.2 256 0.5 0.2 1.5 0.2 171 0.33 0.2 1 0.2 128 0.25 0.2 0.75 0.2 --------------------------------------------------------- Since the spacecraft was to undertake a lengthy trip in space (over 6.5 months) before making its prime measurements and since a long useful lifetime of the spacecraft was anticipated, a commandable calibration signal was included. The signal is a dc current applied to an external winding surrounding each sensor so that the readings changed by approximately 40 nT. The current is applied for a telemetry major frame which is 64 minor frames. During a minor frame the magnetometer is read out either once or three times. The reference voltage in the instrument's 12-bit analog-to- digital converter is used to power the calibrate signal. Since this voltage also is the reference for the digitization of the signal only a change in the analog circuitry will result in variations in the apparent size of the calibrate signal. To check the invariance of the reference voltage, it is digitized by the spacecraft analog- to-digital converter and telemetered to earth. The Basic Magnetometer The basic magnetometer has been described by Snare and Means [5] and is similar in many respects to the ISEE-1 and 2 magnetometers [6]. Briefly it is a fluxgate magnetometer with large loop gain and feedback. The sensors are ring core types manufactured by the Naval Surface Weapons Laboratory, White Oak [7]. The drive voltage is a very clean 7.25-kHz sine wave with an amplitude of about 4-V peak- to-peak. The drive current is approximately 159 mA. The detected signal is the second harmonic of the drive frequency, detected in a double sideband suppressed carrier mode. The open-loop gain is unity at 300 Hz and approaches 10 to the 8 at dc. The closed-loop system response is flat with a first-order corner at 300 Hz. Construction The basic magnetometer uses integrated-circuit operational amplifiers mounted on a two-sided printed circuit board. The digital circuit are all CMOS integrated circuits mounted on stitch wired boards. The electronic assembly chassis is all magnesium. Sensor assemblies were machined from epoxy fiberglass stock. Conceptual and preliminary design was performed at UCLA with detailed design and fabrication at Westinghouse Electric Company, Baltimore, MD. The electronic unit mounted on the main body of the spacecraft measures 15 X 22 X 15 cm and weighs 1.7 kg. The inboard sensor assembly measures 6 X 7 X 6 cm and weighs 100g. The outboard sensor assembly measures 8 X 5 X 4.4 cm and weighs 170 g. The total power required is 2.2 W at 22-V dc. The sensors are mounted at the end of a 5 meter boom. The boom is radially extended from a point 240 degrees counter- clockwise (direction of spacecraft spin) around from the x-axis of the spacecraft (looking down) on the side with the despun antenna and instruments. The sun sensor is about 355 degrees measured in this coordinate system so that the boom is 115 degrees behind the sun sensor. The T sensor points perpendicular to the boom axis. Initial Operation The magnetometer was turned on shortly after launch and has operated continuously since that time except for brief periods at orbit injection and during the long eclipse season. The instrument has operated flawlessly. Daily checks of the instrument calibration show no change in gain in over one year's operation in space. Despite the fact that Venus had been probed many times before, including two Soviet orbiting vehicles, much has been learned during the first year's operation. We will start in the solar wind and work inwards to the planet rather than attempt to prioritize the findings. First, the bow shock, which stands in front of the planet and deflects and heats the supersonic solar wind when it encounters the planetary obstacle, is significantly further out now than it was in 1975 when the shock was probed by the Venera 9 and 10 orbiters [8]. This suggests that there has been a change in the Venus ionosphere since then as the solar cycle progressed towards solar maximum. Second, the bow shock is much weaker than the terrestrial bow shock [9]. The phenomenon could be caused by slowing down of the solar wind before it reached the bow shock by mass addition from the Venus hydrogen geocorona, or by absorption of solar wind by the upper atmosphere of Venus. Third, the shock does not appear to be asymmetric about the solar wind flow direction as reported earlier from a more limited set of Venera bow shock crossings [10]. Fourth the ionopause, the upper limit of the ionosphere, appears to be a tangential discontinuity with approximate pressure balance maintained between the thermal pressure of the electrons and ions in the ionosphere and the magnetic field external to the ionosphere [11]. The magnetic field strength in the ionosphere is generally very low [12]. Fig. 1 shows the magnetic field strength on four successive passes through the ionosphere. Most often low field regions interspersed with narrow twisted filaments of field or flux ropes [13] are observed. Occasionally a more steady field is found as in orbit 163. Finally, we have not yet found any evidence for a planetary field. The upper limit to the Venus magnetic dipole moment is now much less than theoretical expectations [14]. Acknowledgement The success of this investigation is due to the effort of a large number of individuals. At UCLA we are particularly grateful to F.R. George and B. Greer who assisted in the design and fabrication of the ground support equipment and testing of the instrument. At Westinghouse the final design and fabrication was skillfully directed by A. Plitt. We benefitted much from the advice and guidance of M. Larson of ONR, and D. Sinnott and E. Tischler of Ames, and appreciate the excellent spacecraft provided by the Ames Research Center - Hughes Aircraft team led by C.F. Hall and S. Dorfman, respectively. Special thanks go to E. Iufer and R. Murphy of the Ames Research Center for their assistance in calibrating the magnetometers. References [1] E.J. Smith, L. Davis, Jr., P.J. Coleman, Jr., and C.P. Sonett, Science, vol. 139, p. 909, 1963. [2] Sh. Sh. Dolginov, Ye. G. Yeroshenko and L. Davis, 'On the nature of the magnetic field near Venus,' Kosmich. Issled., vol. 7, p. 747, 1969. [3] C.T. Russell, 'The magnetic moment of Venus: Venera-4 measurements reinterpreted,' Geophys. Res. Lett., vol. 3, p. 125, 1976. [4] F. Busse, 'Generation of planetary field by convection,' Phys. Earth Planet. Int., vol. 12, p. 350, 1976. [5] R.C. Snare and J.D. Means, 'A magnetometer for the Pioneer Venus mission,' IEEE Trans. Magnetics, vol. MAG-13, p. 1107, 1977. [6] C.T. Russell, 'The ISEE-1 and 2 fluxgate magnetometers,' IEEE Trans. Geosci. Electron., vol. GE-16, p. 239, 1978. [7] D.I. Gordon and R.E. Brown, 'Recent advances in fluxgate magnetometry,' IEEE Trans. Magnetics, vol. MAG-8, p. 76, 1972. [8] J.A. Slavin, R.C. Elphic, and C.T. Russell, 'A comparison of Pioneer Venus and Venera bow shock observations: Evidence for a solar cycle variation,' Geophys. Res. Lett., 1979. [9] C.T. Russell, R.C. Elphic, and J.A. Slavin, 'On the strength of the Venus bow shock,' Nature, in press, 1979. [10] J.A. Slavin, R.C. Elphic, C.T. Russell, J.H. Wolfe, and D.S. Intriligator, 'Position and shape of the Venus bow shock: Pioneer Venus orbiter magnetometer observations,' Geophys. Res. Lett., 1979. [11] R.C. Elphic, C.T. Russell, J.A. Slavin, L. Brace and A. Nagy, ' The location of the dayside ionopause of Venus: Pioneer Venus Orbiter magnetometer observations,' Geophys. Res. Lett., submitted, 1979. [12] C.T. Russell, R.C. Elphic, and J.A. Slavin, 'Initial Pioneer Venus magnetic field results: Dayside observations,' Science, vol. 203, p. 745, 1979. [13] C.T. Russell and R.C. Elphic, 'Observation of magnetic flux ropes in Venus ionosphere,' Nature, vol. 279, p. 616, 1979. [14] C.T. Russell, R.C. Elphic, and J.A. Slavin, 'Initial Pioneer Venus magnetic field results: Nightside observations,' Science, vol 205, p. 114, 1979." /* /*************************************************************************** /* SCIENTIFIC_OBJECTIVES_SUMMARY = " The Earth's atmosphere is shielded from the solar wind, the rapidly expanding ionized gas of the sun's outer corona, by a moderately strong magnetic field generated by a dynamo inside the liquid core of the earth. That Venus is not thus shielded was evident from the measurements of the earliest probes to Venus [1], [2]. It was not certain that these measurements indicated that Venus had no intrinsic field. Rather, the existence of a small intrinsic field was still possible [3], and in fact expected from dynamo models [4]. A measure of the size of any Venus moment would be a check on our understanding of planetary dynamos. Furthermore, the solar wind was thought to interact directly with the upper atmosphere of Venus, a situation quite unlike that probed on other planetary missions. (Mars may have a similar interaction with the solar wind, but Martian studies have concentrated on the surface and lower atmosphere rather than the upper atmosphere.) Such an interaction is only poorly understood. It is possible that the weak magnetic field of the solar wind could act to shield the upper atmosphere by inhibiting the solar wind penetration into the atmosphere. Thus it was important for both aeronomical and planetological reasons to measure the magnetic field in the near vicinity of Venus. Only from an orbiter with a controllable periapsis altitude could the requisite series of low-altitude measurements be made. The intent of the Pioneer Venus mission was to be both comprehensive and low cost. The former requirement led to the inclusion of a large number of instruments and the need for a moderately high data rate and hence a despun antenna. The latter requirement led to a spinning spacecraft, a minimum magnetic cleanliness program and no allowance for redundancy. Even with a despun antenna the Pioneer Venus spacecraft would sometimes have to transmit data at rates as low as 8 bits/s when Venus was on the far side of the sun and the deep space net telemetry stations were being used for outer planet missions. These constraints made for some exacting design challenges both for the spacecraft design team and the magnetometer team. References [1] E.J. Smith, L. Davis, Jr., P.J. Coleman, Jr., and C.P. Sonett, Science, vol. 139, p. 909, 1963. [2] Sh. Sh. Dolginov, Ye. G. Yeroshenko and L. Davis, 'On the nature of the magnetic field near Venus,' Kosmich. Issled., vol. 7, p. 747, 1969. [3] C.T. Russell, 'The magnetic moment of Venus: Venera-4 measurements reinterpreted,' Geophys. Res. Lett., vol. 3, p. 125, 1976." /* /*************************************************************************** /* INSTRUMENT_CALIBRATION_DESC = " Since the spacecraft was to undertake a lengthy trip in space (over 6.5 months) before making its prime measurements and since a long useful lifetime of the spacecraft was anticipated, a commandable calibration signal was included. The signal is a dc current applied to an external winding surrounding each sensor so that the readings changed by approximately 40 nT. The current is applied for a telemetry major frame which is 64 minor frames. During a minor frame the magnetometer is read out either once or three times. The reference voltage in the instrument's 12-bit analog-to- digital converter is used to power the calibrate signal. Since this voltage also is the reference for the digitization of the signal only a change in the analog circuitry will result in variations in the apparent size of the calibrate signal. To check the invariance of the reference voltage, it is digitized by the spacecraft analog- to-digital converter and telemetered to earth. This cali- bration signal was exercised regularly over the course of the mission until entry and no change in gain was detected." /* /*************************************************************************** /* OPERATIONAL_CONSID_DESC = " It is necessary to limit the bandwidth of the magnetometer so that signals of frequency too high to be resolved by the telemetry system, do not enter the sampling circuitry. The maximum frequency that can be properly analyzed is half the sampling frequency and is called the Nyquist frequency. If signals enter the telemetry stream at frequencies above the Nyquist frequency they appear to occur at a frequency below their true frequency. This process is called aliasing and the filters in the instrument that prevent this are called aliasing filters, although a more proper name would be nonaliasing filters. Since the telemetry rate of the spacecraft varied over an enormous range, the corner frequency of the aliasing filters too had to vary. These corner frequencies were controlled automatically according to the instrument sample rate. Depending on the telemetry format the instrument could sample once per minor frame (512 bits) or three times. These modes were called SLOW sampling and FAST sampling, respectively. At telemetry rates of 512 b/s and below the corner frequency was kept fixed at 0.2 Hz. The resultant sample rates and 3 dB points are given in Table I. When the sample rate drops below 0.5 Hz, onboard averaging is generally used." /* /*************************************************************************** /* END_OBJECT = INSTINFO /* Template: Instrument Detector Template Rev: 19890121 /* Note: This template shall be repeated for each /* detector utilized by an instrument. /* OBJECT = INSTDETECT DETECTOR_ID = PVOMAG_T DETECTOR_TYPE = "RING CORE" DETECTOR_ASPECT_RATIO = "N/A" MINIMUM_WAVELENGTH = "N/A" MAXIMUM_WAVELENGTH = "N/A" NOMINAL_OPERATING_TEMPERATURE = 273 DETECTOR_DESC = " The basic magnetometer has been described by Snare and Means [5] and is similar in many respects to the ISEE-1 and 2 magnetometers [6]. Briefly it is a fluxgate magnetometer with large loop gain and feedback. The sensors are ring core types manufactured by the Naval Surface Weapons Laboratory, White Oak [7]. The drive voltage is a vary clean 7.25-kHz sinewave with an amplitude of about 4-V peak- to-peak. The drive current is approximately 159 mA. The detected signal is the second harmonic of the drive frequency, detected in a double sideband suppressed carrier mode. The open-loop gain is unity at 300 Hz and approaches 10 to the 8 at dc. The closed-loop system response is flat with a first-order corner at 300 Hz. References [5] R.C. Snare and J.D. Means, 'A magnetometer for the Pioneer Venus mission,' IEEE Trans. Magnetics, vol. MAG-13, p. 1107, 1977. [6] C.T. Russell, 'The ISEE-1 and 2 fluxgate magnetometers,' IEEE Trans. Geosci. Electron., vol. GE-16, p. 239, 1978. [7] D.I. Gordon and R.E. Brown, 'Recent advances in fluxgate magnetometry,' IEEE Trans. Magnetics, vol. MAG-8, p. 76, 1972." /*************************************************************************** SENSITIVITY_DESC = " Our next design challenge was the problem of the occasional very low telemetry rates. At 8 b/s, we would obtain only one vector sample of the magnetic field every 21 or 64 s depending on which telemetry format was being used. Since the spin period of the spacecraft was 12 s these low data rates were insufficient to enable the amplitude and phase of the signal from the sensors with components in the spin plane to be determined. Thus it was necessary to 'despin' the measurements to an inertial frame before transmittal. The optimum despinning routine would be to multiply the data by sine and cosine waves in-phase with the rotation and average over an integral number of spin periods. Again weight and power were not available for the optimum approach and we used a Walsh transform rather than a Fourier transform. The Walsh transform is basically the multiplication of the data by two square waves in quadrature at the spin period. Overlapped averages are accumulated in six averaging registers, half of which were read out one telemetry cycle and the other half the next. There are 64 samples in each average which could be spread over 1, 2, or 4 spins, resulting in overlapped samples being returned every 1/2, 1, or 2 spins or every 6, 12, or 24 s. Thus at the lowest bit rate, 8 b/s, when the telemetry format is returning a vector every 21 s, accurate vector measurements are obtained. As mentioned above, well below the spin frequency one can determine the two components of the field in the spin plane from one sensor with a component in the spin plane. Thus in normal operation at low bit rates (called NORMAL MODE) the instrument performs a Walsh transform on only the outboard sensor in the spin plane (called the T sensor). The inphase average of T and quadrature average of T are stored along with the usual average of the readings from the outboard sensor parallel to the spin axis (the P sensor). This scheme provides only a measure of the field at the outboard sensor. Another operating mode (Gradiometer mode) was included to provide in-phase and quadrature transforms and a regular average of the inboard G sensor. In the Gradiometer mode all rates remain the same. The only difference is that the G sensor averages are stored in the second set of three averaging registers at the expense of overlapped averages. To obtain both the desired range (+/- 128 nT) and resolution (+/- 1/16 nT), a 12-bit analog-to-digital conversion was used. To optimize the utilization of the available telemetry, 32 bits per vector sample, two of the 12-bit samples were converted to floating point words consisting of an eight-bit mantissa and a two-bit exponent by checking the leading bit for zeros and shifting bits if the leading bit was zero. A maximum of three shifts was permitted. The number of shifts formed the exponent. Thus these two measurements had resolution of +/- 1/2 nT when the reading was greater than 64 gamma in magnitude changing to +/- 1/16 nT when the reading was less than 16 nT." END_OBJECT = INSTDETECT /* /************************************************************************* /* OBJECT = INSTDETECT DETECTOR_ID = PVOMAG_P DETECTOR_TYPE = "RING CORE" DETECTOR_ASPECT_RATIO = "N/A" MINIMUM_WAVELENGTH = "N/A" MAXIMUM_WAVELENGTH = "N/A" NOMINAL_OPERATING_TEMPERATURE = 273 DETECTOR_DESC = " The basic magnetometer has been described by Snare and Means [5] and is similar in many respects to the ISEE-1 and 2 magnetometers [6]. Briefly it is a fluxgate magnetometer with large loop gain and feedback. The sensors are ring core types manufactured by the Naval Surface Weapons Laboratory, White Oak [7]. The drive voltage is a vary clean 7.25-kHz sinewave with an amplitude of about 4-V peak- to-peak. The drive current is approximately 159 mA. The detected signal is the second harmonic of the drive frequency, detected in a double sideband suppressed carrier mode. The open-loop gain is unity at 300 Hz and approaches 10 to the 8 at dc. The closed-loop system response is flat with a first-order corner at 300 Hz. References [5] R.C. Snare and J.D. Means, 'A magnetometer for the Pioneer Venus mission,' IEEE Trans. Magnetics, vol. MAG-13, p. 1107, 1977. [6] C.T. Russell, 'The ISEE-1 and 2 fluxgate magnetometers,' IEEE Trans. Geosci. Electron., vol. GE-16, p. 239, 1978. [7] D.I. Gordon and R.E. Brown, 'Recent advances in fluxgate magnetometry,' IEEE Trans. Magnetics, vol. MAG-8, p. 76, 1972." /*************************************************************************** SENSITIVITY_DESC = " Our next design challenge was the problem of the occasional very low telemetry rates. At 8 b/s, we would obtain only one vector sample of the magnetic field every 21 or 64 s depending on which telemetry format was being used. Since the spin period of the spacecraft was 12 s these low data rates were insufficient to enable the amplitude and phase of the signal from the sensors with components in the spin plane to be determined. Thus it was necessary to 'despin' the measurements to an inertial frame before transmittal. The optimum despinning routine would be to multiply the data by sine and cosine waves in phase with the rotation and average over an integral number of spin periods. Again weight and power were not available for the optimum approach and we used a Walsh transform rather than a Fourier transform. The Walsh transform is basically the multiplication of the data by two square waves in quadrature at the spin period. Overlapped averages are accumulated in six averaging registers, half of which were read out one telemetry cycle and the other half the next. There are 64 samples in each average which could be spread over 1, 2, or 4 spins, resulting in overlapped samples being returned every 1/2, 1, or 2 spins or every 6, 12, or 24 s. Thus at the lowest bit rate, 8 b/s, when the telemetry format is returning a vector every 21 s, accurate vector measurements are obtained. As mentioned above, well below the spin frequency one can determine the two components of the field in the spin plane from one sensor with a component in the spin plane. Thus in normal operation at low bit rates (called NORMAL MODE) the instrument performs a Walsh transform on only the outboard sensor in the spin plane (called the T sensor). The inphase average of T and quadrature average of T are stored along with the usual average of the readings from the outboard sensor parallel to the spin axis (the P sensor). This scheme provides only a measure of the field at the outboard sensor. Another operating mode (Gradiometer mode) was included to provide in-phase and quadrature transforms and a regular average of the inboard G sensor. In the Gradiometer mode all rates remain the same. The only difference is that the G sensor averages are stored in the second set of three averaging registers at the expense of overlapped averages. To obtain both the desired range (+/- 128 nT) and resolution (+/- 1/16 nT), a 12-bit analog-to-digital conversion was used. To optimize the utilization of the available telemetry, 32 bits per vector sample, two of the 12-bit samples were converted to floating point words consisting of an eight-bit mantissa and a two-bit exponent by checking the leading bit for zeros and shifting bits if the leading bit was zero. A maximum of three shifts was permitted. The number of shifts formed the exponent. Thus these two measurements had resolution of +/- 1/2 nT when the reading was greater than 64 gamma in magnitude changing to +/- 1/16 nT when the reading was less than 16 nT." END_OBJECT = INSTDETECT /* /************************************************************************* /* OBJECT = INSTDETECT DETECTOR_ID = PVOMAG_G DETECTOR_TYPE = "RING CORE" DETECTOR_ASPECT_RATIO = "N/A" MINIMUM_WAVELENGTH = "N/A" MAXIMUM_WAVELENGTH = "N/A" NOMINAL_OPERATING_TEMPERATURE = 273 DETECTOR_DESC = " The basic magnetometer has been described by Snare and Means [5] and is similar in many respects to the ISEE-1 and 2 magnetometers [6]. Briefly it is a fluxgate magnetometer with large loop gain and feedback. The sensors are ring core types manufactured by the Naval Surface Weapons Laboratory, White Oak [7]. The drive voltage is a vary clean 7.25-kHz sinewave with an amplitude of about 4-V peak- to-peak. The drive current is approximately 159 mA. The detected signal is the second harmonic of the drive frequency, detected in a double sideband suppressed carrier mode. The open-loop gain is unity at 300 Hz and approaches 10 to the 8 at dc. The closed-loop system response is flat with a first-order corner at 300 Hz." /*************************************************************************** SENSITIVITY_DESC = " Our next design challenge was the problem of the occasional very low telemetry rates. At 8 b/s, we would obtain only one vector sample of the magnetic field every 21 or 64 s depending on which telemetry format was being used. Since the spin period of the spacecraft was 12 s these low data rates were insufficient to enable the amplitude and phase of the signal from the sensors with components in the spin plane to be determined. Thus it was necessary to 'despin' the measurements to an inertial frame before transmittal. The optimum despinning routine would be to multiply the data by sine and cosine waves in phase with the rotation and average over an integral number of spin periods. Again weight and power were not available for the optimum approach and we used a Walsh transform rather than a Fourier transform. The Walsh transform is basically the multiplication of the data by two square waves in quadrature at the spin period. Overlapped averages are accumulated in six averaging registers, half of which were read out one telemetry cycle and the other half the next. There are 64 samples in each average which could be spread over 1, 2, or 4 spins, resulting in overlapped samples being returned every 1/2, 1, or 2 spins or every 6, 12, or 24 s. Thus at the lowest bit rate, 8 b/s, when the telemetry format is returning a vector every 21 s, accurate vector measurements are obtained. As mentioned above, well below the spin frequency one can determine the two components of the field in the spin plane from one sensor with a component in the spin plane. Thus in normal operation at low bit rates (called NORMAL MODE) the instrument performs a Walsh transform on only the outboard sensor in the spin plane (called the T sensor). The inphase average of T and quadrature average of T are stored along with the usual average of the readings from the outboard sensor parallel to the spin axis (the P sensor). This scheme provides only a measure of the field at the outboard sensor. Another operating mode (Gradiometer mode) was included to provide in-phase and quadrature transforms and a regular average of the inboard G sensor. In the Gradiometer mode all rates remain the same. The only difference is that the G sensor averages are stored in the second set of three averaging registers at the expense of overlapped averages. To obtain both the desired range (+/- 128 nT) and resolution (+/- 1/16 nT), a 12-bit analog-to-digital conversion was used. To optimize the utilization of the available telemetry, 32 bits per vector sample, two of the 12-bit samples were converted to floating point words consisting of an eight-bit mantissa and a two-bit exponent by checking the leading bit for zeros and shifting bits if the leading bit was zero. A maximum of three shifts was permitted. The number of shifts formed the exponent. Thus these two measurements had resolution of +/- 1/2 nT when the reading was greater than 64 gamma in magnitude changing to +/- 1/16 nT when the reading was less than 16 nT." END_OBJECT = INSTDETECT /* /************************************************************************* /* /* Template: Instrument Electronics Template Rev: 19890121 /* Note: This template shall be repeated for each /* electronics id description utilized by an /* instrument. /* OBJECT = INSTELEC ELECTRONICS_ID = PVOMAG ELECTRONICS_DESC = " The basic magnetometer uses integrated-circuit operational amplifiers mounted on a two-sided printed circuit board. The digital circuit are all CMOS integrated circuits mounted on stitch wired boards. The electronic assembly chassis is all magnesium. Sensor assemblies were machined from epoxy fiberglass stock. Conceptual and preliminary design was performed at UCLA with detailed design and fabrication at Westinghouse Electric Company, Baltimore, MD." END_OBJECT = INSTELEC /* Template: Instrument Filter Template Rev: 19890121 /* Note: This template shall be repeated for each /* filter utilized by an instrument. /* OBJECT = INSTFILTER FILTER_NUMBER = "N/A" FILTER_NAME = "N/A" FILTER_TYPE = "N/A" MINIMUM_WAVELENGTH = "N/A" CENTER_FILTER_WAVELENGTH = "N/A" MAXIMUM_WAVELENGTH = "N/A" MEASUREMENT_WAVE_CALBRT_DESC = "N/A" END_OBJECT = INSTFILTER /* Template: Instrument Optics Template Rev: 19890121 /* Note: This template shall be completed for each /* optical instrument. /* OBJECT = INSTOPTICS TELESCOPE_ID = "N/A" TELESCOPE_FOCAL_LENGTH = "N/A" TELESCOPE_DIAMETER = "N/A" TELESCOPE_F_NUMBER = "N/A" TELESCOPE_RESOLUTION = "N/A" TELESCOPE_TRANSMITTANCE = "N/A" TELESCOPE_T_NUMBER = "N/A" TELESCOPE_T_NUMBER_ERROR = "N/A" TELESCOPE_SERIAL_NUMBER = "N/A" OPTICS_DESC = "N/A" END_OBJECT = INSTOPTICS /* Template: Spacecraft Instrument Offset Template Rev: 19890121 /* Note: This template shall be completed for each /* platform used for instrument positioning. /* OBJECT = SCINSTOFFSET PLATFORM_OR_MOUNTING_NAME = "MAGNETOMETER BOOM" CONE_OFFSET_ANGLE = "N/A" CROSS_CONE_OFFSET_ANGLE = "N/A" TWIST_OFFSET_ANGLE = 0 INSTRUMENT_MOUNTING_DESC = " Since the spacecraft designers were attempting to maximize the use of off-the-shelf hardware from programs without a need for magnetic cleanliness, the decision was made earlier in the program to place the sensors as far away from the center of the spacecraft as possible (approx. 5 m). Since there would be moderately high thrust at orbit injection and interplanetary measurements and deployment of the magnetometer were needed before orbit injection, the boom for the magnetometer was made rigid. This rigid boom was stowed in three hinged sections on top of the spacecraft and deployed by centrifugal force shortly after launch and interplanetary insertion. The despun antenna assembly was expected to be magnetic as were several other subsystems. Furthermore, it was possible that these fields might change during the mission. Monitoring the field at two radial distances would help monitor such changes through the differences between the two readings if the sensors gains and zero levels remained constant. While this feature was desirable it was not affordable within the weight and power allowance of the magnetic fields investigation. A compromise design was to take one of the sensors from the triad on the end of the boom and install it 1/3 of the way back along the boom tilted with respect to the satellite spin axis and at right angles to the sensor in the spin plane. At low frequencies, well below the spacecraft spin frequency, this provided two measures of the field at varying distances from the spacecraft subject to the limitations discussed above. At high frequencies, at which interference was expected to be minimal, the readings could be combined to give the equivalent readings of three mutually orthogonal sensors. Not only did this approach provide a rudimentary gradiometer, but also reassuring redundancy. Only the failure of both sensors with components along the spin axis would have prevented the measurements of three components of the magnetic field. No single sensor failure or other pair of failures would have jeopardized the measurement. The electronic unit mounted on the main body of the spacecraft measures 15 X 22 X 15 cm and weighs 1.7 kg. The inboard sensor assembly measures 6 X 7 X 6 cm and weighs 100g. The outboard sensor assembly measures 8 X 5 X 4.4 cm and weighs 170 g. The total power required is 2.2 W at 22-V dc. The sensors are mounted at the end of a 5 meter boom. The boom is radially extended from a point 240 degrees counter- clockwise (direction of spacecraft spin) around from the x-axis of the spacecraft (looking down) on the side with the despun antenna and instruments. The sun sensor is about 355 degrees measured in this coordinate system so that the boom is 115 degrees behind the sun sensor. The T sensor points perpendicular to the boom axis." END_OBJECT = SCINSTOFFSET /* Template: Instrument Section Template Rev: 19890121 /* Note: This template group shall be repeated for each /* instrument section. /* OBJECT = INSTSECTION SECTION_ID = PVOMAG /* Template: Instrument Section Information Template Rev: 19890121 /* Note: This section shall be completed for each /* instrument section id entered in the instsection /* template. /* OBJECT = INSTSECTINFO SCAN_MODE_ID = "N/A" DATA_RATE = "N/A" SAMPLE_BITS = 12 TOTAL_FOVS = 1 /* Template: Instrument Section Fields Of View Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument section fields of view. /* OBJECT = INSTSECTFOVS FOV_SHAPE_NAME = OMNIDIRECTIONAL HORIZONTAL_PIXEL_FOV = "N/A" VERTICAL_PIXEL_FOV = "N/A" HORIZONTAL_FOV = "N/A" VERTICAL_FOV = "N/A" FOVS = 1 END_OBJECT = INSTSECTFOVS END_OBJECT = INSTSECTINFO /* Template: Instrument Section Parameter Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument section parameter. /* OBJECT = INSTSECTPARM INSTRUMENT_PARAMETER_NAME = "MAGNETIC FIELD COMPONENT" MINIMUM_INSTRUMENT_PARAMETER = UNK MAXIMUM_INSTRUMENT_PARAMETER = UNK NOISE_LEVEL = "N/A" INSTRUMENT_PARAMETER_UNIT = NANOTESLA SAMPLING_PARAMETER_NAME = TIME MINIMUM_SAMPLING_PARAMETER = "N/A" MAXIMUM_SAMPLING_PARAMETER = "N/A" SAMPLING_PARAMETER_INTERVAL = "N/A" SAMPLING_PARAMETER_RESOLUTION = "N/A" SAMPLING_PARAMETER_UNIT = SECOND END_OBJECT = INSTSECTPARM /* Template: Instrument Section Detector Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument section detector id. /* OBJECT = INSTSECTDET DETECTOR_ID = PVOMAG_T END_OBJECT = INSTSECTDET OBJECT = INSTSECTDET DETECTOR_ID = PVOMAG_P END_OBJECT = INSTSECTDET OBJECT = INSTSECTDET DETECTOR_ID = PVOMAG_G END_OBJECT = INSTSECTDET /* Template: Instrument Section Electronics Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument section electronics component. /* OBJECT = INSTSECTELEC ELECTRONICS_ID = PVOMAG END_OBJECT = INSTSECTELEC /* Template: Instrument Section Filter Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument section filter. /* OBJECT = INSTSECTFILT FILTER_NUMBER = "N/A" END_OBJECT = INSTSECTFILT /* Template: Instrument Section Optics Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument section telescope. /* OBJECT = INSTSECTOPTC TELESCOPE_ID = "N/A" END_OBJECT = INSTSECTOPTC END_OBJECT = INSTSECTION /* Template: Instrument Mode Information Template Rev: 19890121 /* Note: This template shall be repeated for each /* instrument mode. /* OBJECT = INSTMODEINFO INSTRUMENT_MODE_ID = NORMAL_FAST GAIN_MODE_ID = UNK DATA_PATH_TYPE = "REAL TIME" INSTRUMENT_POWER_CONSUMPTION = 2.2 INSTRUMENT_MODE_DESC = " As mentioned above, well below the spin frequency one can determine the two components of the field in the spin plane from one sensor with a component in the spin plane. Thus in normal operation at low bit rates (called NORMAL MODE) the instrument performs a Walsh transform on only the outboard sensor in the spin plane (called the T sensor). The inphase average of T and quadrature average of T are stored along with the usual average of the readings from the outboard sensor parallel to the spin axis (the P sensor). This scheme provides only a measure of the field at the outboard sensor. It is necessary to limit the bandwidth of the magnetometer so that signals of frequency too high to be resolved by the telemetry system, do not enter the sampling circuitry. The maximum frequency that can be properly analyzed is half the sampling frequency and is called the Nyquist frequency. If signals enter the telemetry stream at frequencies above the Nyquist frequency they appear to occur at a frequency below their true frequency. This process is called aliasing and the filters in the instrument that prevent this are called aliasing filters, although a more proper name would be nonaliasing filters. Since the telemetry rate of the spacecraft varied over an enormous range, the corner frequency of the aliasing filters too had to vary. These corner frequencies were controlled automatically according to the instrument sample rate. Depending on the telemetry format the instrument could sample once per minor frame (512 bits) or three times. These modes were called SLOW sampling and FAST sampling, respectively. At telemetry rates of 512 b/s and below the corner frequency was kept fixed at 0.2 Hz. The resultant sample rates and 3 dB points are given in Table I. When the sample rate drops below 0.5 Hz, onboard averaging is generally used. " OBJECT = INSTMODESECT SECTION_ID = PVOMAG END_OBJECT = INSTMODESECT END_OBJECT = INSTMODEINFO OBJECT = INSTMODEINFO INSTRUMENT_MODE_ID = NORMAL_SLOW GAIN_MODE_ID = UNK DATA_PATH_TYPE = "REAL TIME" INSTRUMENT_POWER_CONSUMPTION = 2.2 INSTRUMENT_MODE_DESC = " As mentioned above, well below the spin frequency one can determine the two components of the field in the spin plane from one sensor with a component in the spin plane. Thus in normal operation at low bit rates (called NORMAL MODE) the instrument performs a Walsh transform on only the outboard sensor in the spin plane (called the T sensor). The inphase average of T and quadrature average of T are stored along with the usual average of the readings from the outboard sensor parallel to the spin axis (the P sensor). This scheme provides only a measure of the field at the outboard sensor. It is necessary to limit the bandwidth of the magnetometer so that signals of frequency too high to be resolved by the telemetry system, do not enter the sampling circuitry. The maximum frequency that can be properly analyzed is half the sampling frequency and is called the Nyquist frequency. If signals enter the telemetry stream at frequencies above the Nyquist frequency they appear to occur at a frequency below their true frequency. This process is called aliasing and the filters in the instrument that prevent this are called aliasing filters, although a more proper name would be nonaliasing filters. Since the telemetry rate of the spacecraft varied over an enormous range, the corner frequency of the aliasing filters too had to vary. These corner frequencies were controlled automatically according to the instrument sample rate. Depending on the telemetry format the instrument could sample once per minor frame (512 bits) or three times. These modes were called SLOW sampling and FAST sampling, respectively. At telemetry rates of 512 b/s and below the corner frequency was kept fixed at 0.2 Hz. The resultant sample rates and 3 dB points are given in Table I. When the sample rate drops below 0.5 Hz, onboard averaging is generally used. " OBJECT = INSTMODESECT SECTION_ID = PVOMAG END_OBJECT = INSTMODESECT END_OBJECT = INSTMODEINFO OBJECT = INSTMODEINFO INSTRUMENT_MODE_ID = GRADIOMETER GAIN_MODE_ID = UNK DATA_PATH_TYPE = "REAL TIME" INSTRUMENT_POWER_CONSUMPTION = 2.2 INSTRUMENT_MODE_DESC = " Another operating mode (Gradiometer mode) was included to provide in-phase and quadrature transforms and a regular average of the inboard G sensor. In the Gradiometer mode all rates remain the same. The only difference is that the G sensor averages are stored in the second set of three averaging registers at the expense of overlapped averages." OBJECT = INSTMODESECT SECTION_ID = PVOMAG END_OBJECT = INSTMODESECT END_OBJECT = INSTMODEINFO /* Template: Instrument Reference Information Template Rev: 19890121 /* Note: The following template form part of a standard /* set for the submission of a publication reference /* to the PDS. /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = SMITHETAL1963 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = SCIENCE PUBLICATION_DATE = 1963 REFERENCE_DESC = " Smith, E.J., L. Davis, Jr., P.J. Coleman, Jr., and C.P. Sonett, Science, vol. 139, p. 909, 1963." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "E.J. SMITH" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = DOLGINOVETAL1969 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "KOSMICH. ISSLED." PUBLICATION_DATE = 1969 REFERENCE_DESC = " Dolginov, Sh. Sh., Ye. G. Yeroshenko and L. Davis, 'On the nature of the magnetic field near Venus', Kosmich. Issled., vol. 7, p. 747, 1969." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "SH. SH. DOLGINOV" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = RUSSELL1976 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL RESEARCH LETTERS" PUBLICATION_DATE = 1976 REFERENCE_DESC = " Russell, C.T., 'The magnetic moment of Venus: Venera-4 measurements reinterpreted,' Geophys. Res. Lett., vol. 3, p. 125, 1976." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = BUSSE1976 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "ORIGIN OF PLANETARY MAGNETIC FIELDS" JOURNAL_NAME = "PHYSICS OF THE EARTH AND PLANETARY INTERIORS" PUBLICATION_DATE = 1976 REFERENCE_DESC = " Busse, F., 'Generation of planetary field by convection', Phys. Earth Planet. Int., vol. 12, p. 350, 1976." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "F. BUSSE" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = SNAREETAL1977 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = MAGNETOMETRY JOURNAL_NAME = "IEEE TRANSACTIONS ON MAGNETICS" PUBLICATION_DATE = 1977 REFERENCE_DESC = " Snare,R.C. and J.D. Means, 'A magnetometer for the Pioneer Venus mission', IEEE Trans. Magnetics, vol. MAG-13, p. 1107, 1977." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "ROBERT C. SNARE" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = RUSSELL1978 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "MAGNETOMETRY" JOURNAL_NAME = "IEEE TRANSACTIONS ON GEOSCIENCE AND ELECTRONICS" PUBLICATION_DATE = 1978 REFERENCE_DESC = " Russell, C.T. , 'The ISEE-1 and 2 fluxgate magnetometers', IEEE Trans. Geosci. Electron., vol. GE-16, p. 239, 1978." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = GORDONETAL1972 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = MAGNETOMETRY JOURNAL_NAME = MAGNETICS PUBLICATION_DATE = 1972 REFERENCE_DESC = " Gordon, D.I. and R.E. Brown, 'Recent advances in fluxgate magnetometry', IEEE Trans. Magnetics, vol. MAG-8, p. 76, 1972." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "D.I. GORDON" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = SLAVINETAL1979A OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL RESEARCH LETTERS" PUBLICATION_DATE = 1979 REFERENCE_DESC = " Slavin, J.A., R.C. Elphic, and C.T. Russell, 'A comparison of Pioneer Venus and Venera bow shock observations: Evidence for a solar cycle variation', Geophys. Res. Lett., 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "JAMES A. SLAVIN" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = RUSSELLETAL1979A OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = NATURE PUBLICATION_DATE = 1979 REFERENCE_DESC = " Russell, C.T., R.C. Elphic, and J.A. Slavin, 'On the strength of the Venus bow shock', Nature, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = SLAVINETAL1979B OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL RESEARCH LETTERS" PUBLICATION_DATE = 1979 REFERENCE_DESC = " Slavin, J.A., R.C. Elphic, C.T. Russell, J.H. Wolfe, and D.S. Intriligator, 'Position and shape of the Venus bow shock: Pioneer Venus orbiter magnetometer observations', Geophys. Res. Lett., 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "JAMES A. SLAVIN" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = ELPHICETAL1979 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL RESEARCH LETTERS" PUBLICATION_DATE = 1979 REFERENCE_DESC = " Elphic, R.C., C.T. Russell, J.A. Slavin, L. Brace and A. Nagy, 'The location of the dayside ionopause of Venus: Pioneer Venus Orbiter magnetometer observations', Geophys. Res. Lett., submitted, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "RICHARD C. ELPHIC" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = RUSSELLETAL1979B OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = SCIENCE PUBLICATION_DATE = 1979 REFERENCE_DESC = " Russell, C.T., R.C. Elphic, and J.A. Slavin, 'Initial Pioneer Venus magnetic field results: Dayside observations', Science, vol. 203, p. 745, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = RUSSELLETAL1979C OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = NATURE PUBLICATION_DATE = 1979 REFERENCE_DESC = " Russell,C.T. and R.C. Elphic, 'Observation of magnetic flux ropes in Venus ionosphere', Nature, vol. 279, p. 616, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = RUSSELLETAL1979D OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = SCIENCE PUBLICATION_DATE = 1979 REFERENCE_DESC = " Russell, C.T., R.C. Elphic, and J.A. Slavin, 'Initial Pioneer Venus magnetic field results: Nightside observations', Science, vol 205, p. 114, 1979." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* OBJECT = INSTREFINFO REFERENCE_KEY_ID = RUSSELLETAL1980 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = MAGNETOMETRY JOURNAL_NAME = "IEEE TRANS GEOSCIENCE AND REMOTE SENSING" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Russell, C.T., R.C.Snare, R.E. Elphic, and J.D. Means, ' Pioneer Venus Orbiter Fluxgate Magnetometer', IEEE Trans. Geo. Elec., vol. GE-18, no.1, p. 32, 1980." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = INSTREFINFO /* END_OBJECT = SCINSTRUMENT /*============================================================================*/ /*********Spacecraft Data Set Template*****************************************/ /************************************ Rev: 19890121****************************/ /* MODIFICATIONS: */ /* Note: The following templates form part of a standard set */ /* for the submission of a single dataset to the PDS. */ /* Hierarchy: SCDATASET */ /* DATASETINFO */ /* DATASETTARG */ /* DSPARMINFO */ /* SCDSHOST */ /* DSREFINFO */ /* REFERENCE */ /* REFAUTHORS */ OBJECT = SCDATASET DATA_SET_ID = "PVO-V-OMAG-4--SCCOORDS-24SEC-V1.0" OBJECT = DATASETINFO DATA_SET_NAME = "PVO VENUS MAG RESAMPLED SC COORDS 24SEC AVGS V1.0" DATA_SET_COLLECTION_MEMBER_FLG = N START_TIME = 1978-12-05T07:20:07.282 STOP_TIME = 1988-10-16T06:19:10.425 NATIVE_START_TIME = UNK NATIVE_STOP_TIME = UNK DATA_OBJECT_TYPE = "TIME SERIES" DATA_SET_RELEASE_DATE = 1993-09-01 PROCESSING_LEVEL_ID = 4 PRODUCER_FULL_NAME = "MURIEL KNIFFIN" PRODUCER_INSTITUTION_NAME = "UCLA" SOFTWARE_FLAG = Y DETAILED_CATALOG_FLAG = N PROCESSING_START_TIME = 1991-11-06 PROCESSING_STOP_TIME = UNK DATA_SET_DESC = " This dataset contains vectors collected by the Pioneer Venus Orbiter (previously Pioneer 12) Magnetometer which have been averaged over two spin periods (approximately 24 seconds). The averaging intervals are overlapped and data are output on single spin period centers, the time stamp corresponding to the center of the averaging window. This results in an unevenly sampled dataset as the spin period varies. The amplitude of the ''flutter'' in the averaging window size is generally less than 0.004 seconds in the 12 second period of an orbit. Orbits that have spin period adjustment thruster firings will have larger variations in the output time steps, but such adjustments are seldom, if ever, done in the hour surrounding periapsis. The data are provided in spacecraft coordinates whose system has it Z axis antiparallel to the spacecraft spin axis during orbit. This choice maintained the Z axis along roughly the Earth's ecliptic north pole. Late in the mission when it was believed that the shadowing of the solar panels by the booms was causing a problem, the spin axis was moved to the pole of the Venus orbital plane. The X-axis of the spacecraft coordinate system is toward the sun along the projection of the Venus Sun line on the spacecraft equatorial (X-Y) plane. The Y axis is chosen to form a right handed orthogonal triad if the axis are selected in alphabetical order. Hence, the Y direction points roughly opposite to the direction of Venus motion about the sun. Software is provided which allows users to convert the magnetic field data from S/C coordinates to geophysical coordinates. The program PVROT will rotate the data into Venus Solar orbital (VSO) coordinates using the magnetic field data and the ephemeris data. Other datasets on the CD-ROM are the Ephemeris which contains spacecraft position in Venus Solar Orbital coordinates, spacecraft altitude, solar zenith angle, Venus centered longitude and latitude, spacecraft spin axis components, celestial longitude and latitude of the spacecraft, celestial longitude of the earth, and the Sun-spacecraft range. Other ancillary datasets are the: 1) phase and offset which contains the phase amplitude of sun synchronous modulation of the 4 signals (E100, E730, E5.4 and E30K), and offsets of the G sensor. 2) The engineering dataset which contains temperatures, magnetometer modes, magnetometer sample format, magnetometer spin average select, telemetry data format, telemetry bit rate, spacecraft spin period, pulse time, the difference between the Sun pulse time and the Rip pulse time, and the pulse time flag. 3) The instrument status dataset which contains amplitudes of spin ripple, differences between amplitudes, ratio of the amplitudes, phase differences between pseudosensors, average field seen by the pseudosensors, cosine amplitude, and sine amplitude." CONFIDENCE_LEVEL_NOTE = " These data have been reprocessed several times during the course of the mission. Each successive reprocessing has eliminated some of the problems found in earlier version of the data. Please bring to the attention of the original investigator any suspicious section of data. No zero level correction has been applied to the data because of the small size of the determined zero level. " END_OBJECT = DATASETINFO OBJECT = DATASETTARG TARGET_NAME = VENUS END_OBJECT = DATASETTARG OBJECT = DSPARMINFO SAMPLING_PARAMETER_NAME = TIME SAMPLING_PARAMETER_RESOLUTION = 24. MINIMUM_SAMPLING_PARAMETER = "N/A" MAXIMUM_SAMPLING_PARAMETER = "N/A" SAMPLING_PARAMETER_INTERVAL = 12. MINIMUM_AVAILABLE_SAMPLING_INT = 0.08333 SAMPLING_PARAMETER_UNIT = SECOND DATA_SET_PARAMETER_NAME = "MAGNETIC FIELD COMPONENT" NOISE_LEVEL = 0.001 DATA_SET_PARAMETER_UNIT = NANOTESLA END_OBJECT = DSPARMINFO OBJECT = SCDSHOST INSTRUMENT_HOST_ID = PVO INSTRUMENT_ID = OMAG END_OBJECT = SCDSHOST OBJECT = DSREFINFO REFERENCE_KEY_ID = RUSSELLETAL1980 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "MAGNETOMETRY" JOURNAL_NAME = "IEEE TRANS GEOSCIENCE AND REMOTE SENSING" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Russell, C.T., R.C. Snare, J.D. Means and R.C. Elphic, 'Pioneer Venus Orbiter Fluxgate Magnetometer', Ieee Trans. Geo. Elec., vol. GE 18, no. 1 p. 32, 1980." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = ELPHICETAL1980A OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL RESEARCH LETTERS" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Elphic R.C., C.T. Russell, J.A. Slavin, L.H. Brace, and A.F. Nagy, 'The location of the dayside ionopause of Venus: Pioneer Venus Orbiter Magnetometer observations', Geophys. Res. Lett., vol. 7, no. 8, p. 561, 1980." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "RICHARD C. ELPHIC" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = ELPHICETAL1980B OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Elphic R.C., C.T. Russell, J.A. Slavin, and L.H. Brace, 'Observations of the dayside ionopause and ionosphere of Venus', J. Geophys. Res., vol. 85, no. A13, p. 7679, 1980." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "RICHARD C. ELPHIC" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = LUHMANNETAL1981 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL RESEARCH LETTERS" PUBLICATION_DATE = 1981 REFERENCE_DESC = " Luhmann J.G., R.C. Elphic, C.T. Russell, and J.A. Slavin, 'Observations of large scale steady magnetic fields in the nightside Venus ionosphere and near wake', Geophys. Res. Lett., vol. 8, no. 5, p. 517, 1981." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "JANET G. LUHMANN" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = RUSSELLETAL1981 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL RESEARCH LETTERS" PUBLICATION_DATE = 1981 REFERENCE_DESC = " Russell C.T, J.G. Luhmann, and R.C. Elphic, 'The distant bow shock and magnetotail of Venus: Magnetic field and plasma wave observations', Geophys. Res. Lett., vol. 8, no. 7, p. 843, 1981." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = ELPHIC1981 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1981 REFERENCE_DESC = " Elphic, R.C., C.T. Russell, and J.G. Luhmann, 'The Venus ionopause current sheet: Thickness length scale and controlling factors', J. of Geophys., vol. 86, no. A13, p. 11,430, 1981." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "RICHARD C. ELPHIC" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = LUHMANNETAL1982 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1982 REFERENCE_DESC = " Luhmann J.G., C.T. Russell, L.H. Brace, H.A. Taylor, W.C. Knudsen, F.L. Scarf, D.S. Colburn and A. Barnes, 'Pioneer Venus observations of plasma and field structure in the near wake of Venus', J. Geophys. Res., vol. 87, no. A11, p. 9205, 1982." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "JANET G. LUHMANN" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = RUSSELLETAL1985 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL RESEARCH LETTERS" PUBLICATION_DATE = 1985 REFERENCE_DESC = " Russell, C.T., J.G. Luhmann, and J.L. Phillips, 'The location of the subsolar bow shock of Venus: Implications for the obstacle shape', Geophys. Res. Lett., vol. 12, no. 10, p.627, 1985." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = PHILLIPSETAL1986 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1986 REFERENCE_DESC = " Phillips,J.L., J.G. Luhmann, and C.T. Russell, 'Magnetic configuration of the Venus magnetosheath', J. Geophys. Res., vol. 91, no. A7 p. 7931, 1986." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "JOHN L. PHILLIPS" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = SAUNDERSETAL1986 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS " JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1986 REFERENCE_DESC = " Saunders, M.A., and C.T. Russell, 'Average dimension and magnetic structure of the distant Venus magnetotail', J Geophys. Res., vol.91, no.A5 p.5589, 1986." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "M A. SAUNDERS" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = MCCOMASETAL1986 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1986 REFERENCE_DESC = " McComas,D.J., H.E. Spence, C.T. Russell, and M.A. Saunders, 'The average magnetic field draping and consistent plasma properties of the Venus magnetotail' J. Geophys. Res., vol 91, no. A7, p. 7939, 1986." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DAVID. J. MCCOMAS" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = PHILLIPSETAL1987 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1987 REFERENCE_DESC = " Phillips, J.L., and C.T. Russell, 'Upper limit on the intrinsic magnetic field of Venus', J. of Geophys. Res, vol. 93, no. A3, p. 2253, 1987." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "JOHN L. PHILLIPS" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = RUSSELLETAL1988 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1988 REFERENCE_DESC = " Russell, C.T., E. Chou, J.G. Luhmann, P. Gazis, L.H. Brace and W.R. Hoegy, 'Solar and interplanetary control of the location of the Venus bow shock', J. of Geophys. Res, vol. 93, no. A6, p. 5461, 1988." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = RUSSELL1990 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL MONOGRAPH" PUBLICATION_DATE = 1990 REFERENCE_DESC = " Russell,C.T., 'Magnetic flux ropes in the ionosphere of Venus', Geophysical Monograph, vol. 58, p. 413" OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = ORLOWSKIETAL1991 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1991 REFERENCE_DESC = " Orlowski D.S., and C.T. Russell, 'ULF waves upstream of the Venus Bow Shock: Properties of one-hertz waves ', J. Geophys. Res., vol. 96, no. A7, p. 11271, 1991." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DARIUS S. ORLOWSKI" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO END_OBJECT = SCDATASET /*============================================================================*/ /**********Spacecraft Data Set Template********************Rev: 19890121 */ /* MODIFICATIONS: */ /* Note: The following templates form part of a standard set */ /* for the submission of a single dataset to the PDS. */ /* Hierarchy: SCDATASET */ /* DATASETINFO */ /* DATASETTARG */ /* DSPARMINFO */ /* SCDSHOST */ /* DSREFINFO */ /* REFERENCE */ /* REFAUTHORS */ OBJECT = SCDATASET DATA_SET_ID = "PVO-V-OMAG-3--SCCOORDS-HIRES-V1.0" OBJECT = DATASETINFO DATA_SET_NAME = "PVO VENUS MAG CALIBRATED SC COORDINATES HIGH RES V1.0" DATA_SET_COLLECTION_MEMBER_FLG = N START_TIME = 1978-12-05T07:20:07.282 STOP_TIME = 1988-10-16T06:19:43.829 NATIVE_START_TIME = UNK NATIVE_STOP_TIME = UNK DATA_OBJECT_TYPE = TIME_SERIES DATA_SET_RELEASE_DATE = 1993-09-01 PROCESSING_LEVEL_ID = 4 PRODUCER_FULL_NAME = "MURIEL KNIFFIN" PRODUCER_INSTITUTION_NAME = UCLA SOFTWARE_FLAG = Y DETAILED_CATALOG_FLAG = N PROCESSING_START_TIME = 1991-11-06 PROCESSING_STOP_TIME = UNK DATA_SET_DESC = " This dataset contains vectors collected by the Pioneer Venus Orbiter (previously Pioneer 12) Magnetometer. The data are provided in spacecraft coordinates. In one format, apoapsis B, the magnetometer can be commanded to return 3 vectors per minor frame. In most others it transmits one vector per minor frame. In one format, periapsis E, it has no words in a minor frame. At very low sampling rates at which time the sine wave due to spacecraft spin could not be resolved. The magnetometer values are despun, and averaged on board using a Walsh transform (square wave) in phase and in quadrature with the sun. The averaged despun magnetometer data could be sampled at the rate of once per spin, once every two spins or once every 4 spins. Each sample was an overlapped average of an interval twice as long as the interval sample period to avoid aliasing. Software is provided to which allows users to convert the magnetic field data from S/C coordinates to geophysical coordinates. The program PVROT will rotate the data into Venus Solar Orbital (VSO) coordinates using the magnetic filed data and the ephemeris data. Other datasets on the CD-ROM are the Ephemeris which contains spacecraft position in Venus Solar Orbital coordinates, spacecraft altitude, solar zenith angle, Venus centered longitude and latitude, spacecraft spin axis components, celestial longitude and latitude of the spacecraft, celestial longitude of the earth, and the Sun-spacecraft range. Other ancillary datasets are the: 1) phase and offset which contains the phase amplitude of sun synchronous modulation of the 4 signals (E100, E730, E5.4 and E30K), and offsets of the G sensor. 2) The engineering dataset which contains temperatures, magnetometer modes, magnetometer sample format, magnetometer spin average select, telemetry data format, telemetry bit rate, spacecraft spin period, pulse time, the difference between the Sun pulse time and the Rip pulse time, and the pulse time flag. 3) The instrument status dataset which contains amplitudes of spin ripple, differences between amplitudes, ratio of the amplitudes, phase differences between pseudosensors, average field seen by the pseudosensors, cosine amplitude, and sine amplitude." CONFIDENCE_LEVEL_NOTE = " These data have been reprocessed several times during the course of the mission. Each successive reprocessing has eliminated some of the problems found in earlier version of the data. Please bring to the attention of the original investigator any suspicious section of data. No zero level correction has been applied to the data because of the small size of the determined zero level." END_OBJECT = DATASETINFO OBJECT = DATASETTARG TARGET_NAME = VENUS END_OBJECT = DATASETTARG OBJECT = DSPARMINFO SAMPLING_PARAMETER_NAME = TIME SAMPLING_PARAMETER_RESOLUTION = "N/A" MINIMUM_SAMPLING_PARAMETER = "N/A" MAXIMUM_SAMPLING_PARAMETER = "N/A" SAMPLING_PARAMETER_INTERVAL = "N/A" MINIMUM_AVAILABLE_SAMPLING_INT = .08333 SAMPLING_PARAMETER_UNIT = SECOND DATA_SET_PARAMETER_NAME = "MAGNETIC FIELD COMPONENT" NOISE_LEVEL = 0.001 DATA_SET_PARAMETER_UNIT = NANOTESLA END_OBJECT = DSPARMINFO OBJECT = SCDSHOST INSTRUMENT_HOST_ID = PVO INSTRUMENT_ID = OMAG END_OBJECT = SCDSHOST OBJECT = DSREFINFO REFERENCE_KEY_ID = RUSSELLETAL1980 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "MAGNETOMETRY" JOURNAL_NAME = "IEEE TRANS GEOSCIENCE AND REMOTE SENSING" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Russell, C.T., R.C. Snare, J.D. Means and R.C. Elphic, 'Pioneer Venus Orbiter Fluxgate Magnetometer', Ieee Trans. Geo. Elec., vol. GE 18, no. 1 p. 32, 1980." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = ELPHICETAL1980A OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL RESEARCH LETTERS" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Elphic R.C., C.T. Russell, J.A. Slavin, L.H. Brace, and A.F. Nagy, 'The location of the dayside ionopause of Venus: Pioneer Venus Orbiter Magnetometer observations', Geophys. Res. Lett., vol. 7, no. 8, p. 561, 1980." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "RICHARD C. ELPHIC" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = ELPHICETAL1980B OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1980 REFERENCE_DESC = " Elphic R.C., C.T. Russell, J.A. Slavin, and L.H. Brace, 'Observations of the dayside ionopause and ionosphere of Venus', J. Geophys. Res., vol. 85, no. A13, p. 7679, 1980." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "RICHARD C. ELPHIC" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = LUHMANNETAL1981 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL RESEARCH LETTERS" PUBLICATION_DATE = 1981 REFERENCE_DESC = " Luhmann J.G., R.C. Elphic, C.T. Russell, and J.A. Slavin, 'Observations of large scale steady magnetic fields in the nightside Venus ionosphere and near wake', Geophys. Res. Lett., vol. 8, no. 5, p. 517, 1981." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "JANET G. LUHMANN" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = RUSSELLETAL1981 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL RESEARCH LETTERS" PUBLICATION_DATE = 1981 REFERENCE_DESC = " Russell C.T, J.G. Luhmann, and R.C. Elphic, 'The distant bow shock and magnetotail of Venus: Magnetic field and plasma wave observations', Geophys. Res. Lett., vol. 8, no. 7, p. 843, 1981." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = ELPHIC1981 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1981 REFERENCE_DESC = " Elphic, R.C., C.T. Russell, and J.G. Luhmann, 'The Venus ionopause current sheet: Thickness length scale and controlling factors', J. of Geophys., vol. 86, no. A13, p. 11,430, 1981." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "RICHARD C. ELPHIC" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = LUHMANNETAL1982 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1982 REFERENCE_DESC = " Luhmann J.G., C.T. Russell, L.H. Brace, H.A. Taylor, W.C. Knudsen, F.L. Scarf, D.S. Colburn and A. Barnes, 'Pioneer Venus observations of plasma and field structure in the near wake of Venus', J. Geophys. Res., vol. 87, no. A11, p. 9205, 1982." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "JANET G. LUHMANN" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = RUSSELLETAL1985 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL RESEARCH LETTERS" PUBLICATION_DATE = 1985 REFERENCE_DESC = " Russell, C.T., J.G. Luhmann, and J.L. Phillips, 'The location of the subsolar bow shock of Venus: Implications for the obstacle shape', Geophys. Res. Lett., vol. 12, no. 10, p.627, 1985." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = PHILLIPSETAL1986 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1986 REFERENCE_DESC = " Phillips,J.L., J.G. Luhmann, and C.T. Russell, 'Magnetic configuration of the Venus magnetosheath', J. Geophys. Res., vol. 91, no. A7 p. 7931, 1986." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "JOHN L. PHILLIPS" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = SAUNDERSETAL1986 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS " JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1986 REFERENCE_DESC = " Saunders, M.A., and C.T. Russell, 'Average dimension and magnetic structure of the distant Venus magnetotail', J Geophys. Res., vol.91, no.A5 p.5589, 1986." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "M A. SAUNDERS" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = MCCOMASETAL1986 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1986 REFERENCE_DESC = " McComas,D.J., H.E. Spence, C.T. Russell, and M.A. Saunders, 'The average magnetic field draping and consistent plasma properties of the Venus magnetotail' J. Geophys. Res., vol 91, no. A7, p. 7939, 1986." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DAVID. J. MCCOMAS" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = PHILLIPSETAL1987 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1987 REFERENCE_DESC = " Phillips, J.L., and C.T. Russell, 'Upper limit on the intrinsic magnetic field of Venus', J. of Geophys. Res, vol. 93, no. A3, p. 2253, 1987." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "JOHN L. PHILLIPS" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = RUSSELLETAL1988 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1988 REFERENCE_DESC = " Russell, C.T., E. Chou, J.G. Luhmann, P. Gazis, L.H. Brace and W.R. Hoegy, 'Solar and interplanetary control of the location of the Venus bow shock', J. of Geophys. Res, vol. 93, no. A6, p. 5461, 1988." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = RUSSELL1990 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "GEOPHYSICAL MONOGRAPH" PUBLICATION_DATE = 1990 REFERENCE_DESC = " Russell,C.T., 'Magnetic flux ropes in the ionosphere of Venus', Geophysical Monograph, vol. 58, p. 413" OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "CHRISTOPHER T. RUSSELL" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO /* OBJECT = DSREFINFO REFERENCE_KEY_ID = ORLOWSKIETAL1991 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "IONOSPHERE OF VENUS" JOURNAL_NAME = "JOURNAL OF GEOPHYSICAL RESEARCH" PUBLICATION_DATE = 1991 REFERENCE_DESC = " Orlowski D.S., and C.T. Russell, 'ULF waves upstream of the Venus Bow Shock: Properties of one-hertz waves ', J. Geophys. Res., vol. 96, no. A7, p. 11271, 1991." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "DARIUS S. ORLOWSKI" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO END_OBJECT = SCDATASET /*============================================================================*/ /***************Data Set Processing Template***********************************/ /* MODIFICATIONS /* 930224 -- MKNIFFIN /* 930308 -- MKNIFFIN/STEVE JOY - update with ctr changes. /* 930309 -- MKNIFFIN/STEVE JOY - new source_data_set_id and */ /* 930310 -- MKNIFFIN ran clean thru jpl lvtool */ /* product_data_set_id */ /* Last changes made /* Template: Data Set Processing Template Rev: 19890121 */ /* */ /* Note: This template shall be repeated for each */ /* source dataset id used in production of the */ /* dataset id in the dataset template. */ /* */ /* Hierarchy: DSPROCESSING */ OBJECT = DSPROCESSING SOURCE_DATA_SET_ID = "N/A" SOFTWARE_NAME = "PVMOV" PRODUCT_DATA_SET_ID = "PVO-V-OMAG/OEFD/OPA-1-EDR---V1.0" END_OBJECT = DSPROCESSING /******************************************************************************/ /* Template: Data Set Processing Template Rev: 19890121 */ /* */ /* Note: This template shall be repeated for each */ /* source dataset id used in production of the */ /* dataset id in the dataset template. */ /* */ /* Hierarchy: DSPROCESSING */ OBJECT = DSPROCESSING SOURCE_DATA_SET_ID = "N/A" SOFTWARE_NAME = "PVO" PRODUCT_DATA_SET_ID ="PVO-V-OMAG-4--SCCOORDS-24SEC-V1.0" END_OBJECT = DSPROCESSING /******************************************************************************/ /* Template: Data Set Processing Template Rev: 19890121 */ /* */ /* Note: This template shall be repeated for each */ /* source dataset id used in production of the */ /* dataset id in the dataset template. */ /* */ /* Hierarchy: DSPROCESSING */ OBJECT = DSPROCESSING SOURCE_DATA_SET_ID = "N/A" SOFTWARE_NAME = "PVO" PRODUCT_DATA_SET_ID = "PVO-V-OMAG-3--SCCOORDS-HIRES-V1.0" END_OBJECT = DSPROCESSING /*=============================================================================/ /***********************Parameter Template*************************************/ /***********************OMAG Parameter Template********************************/ /* MODIFICATIONS: /* 930310: MKNIFFIN ran clean for jpl lvtool. /* Template: Parameter Template Rev: 19890121 */ /* */ /* Note: This template shall be completed for each combination */ /* of data set parameter name, instrument parameter */ /* name and instrument host id associated with a dataset. */ /* */ /* Hierarchy: PARAMETER */ OBJECT = PARAMETER INSTRUMENT_HOST_ID ="PVO" DATA_SET_PARAMETER_NAME ="MAGNETIC FIELD VECTOR" INSTRUMENT_PARAMETER_NAME ="MAGNETIC FIELD COMPONENT" IMPORTANT_INSTRUMENT_PARMS = 1 END_OBJECT = PARAMETER /**********************OMAG Parameter Desc. Template **************************/ /* MODIFICATIONS: /* Template: Data Set Instrument Parameter Description Template Rev: 19890121 */ /* */ /* Note: This template shall be completed for any */ /* data set or instrument parameter description. */ /* */ /* Hierarchy: DSINSTPARMD */ OBJECT = DSINSTPARMD DATA_SET_OR_INSTRUMENT_PARM_NM = "MAGNETIC FIELD VECTOR" DATA_SET_OR_INST_PARM_DESC = " A derived parameter which combines the 3 orthogonal magnetic field component measurements." END_OBJECT = DSINSTPARMD /**********************OMAG Parameter Desc. Template **************************/ /* MODIFICATIONS: /* Template: Data Set Instrument Parameter Description Template Rev: 19890121 */ /* */ /* Note: This template shall be completed for any */ /* data set or instrument parameter description. */ /* */ /* Hierarchy: DSINSTPARMD */ OBJECT = DSINSTPARMD DATA_SET_OR_INSTRUMENT_PARM_NM = "MAGNETIC FIELD COMPONENT" DATA_SET_OR_INST_PARM_DESC = " A measured parameter equaling the magnetic field strength (e.g. in nanoteslas) along a particular axis direction. Usually the three orthogonal axis components are measured by three different sensors." END_OBJECT = DSINSTPARMD /*============================================================================*/ /******************** DATASET TEMPLATE ****************************************/ /* Template: Spacecraft Data Set Template Rev: 19890121 */ /* Note: The following templates form part of a standard set */ /* for the submission of a single dataset to the PDS. */ /* Hierarchy: SCDATASET */ /* DATASETINFO */ /* DATASETTARG */ /* DSPARMINFO */ /* SCDSHOST */ /* DSREFINFO */ /* REFERENCE */ /* REFAUTHORS */ OBJECT = SCDATASET DATA_SET_ID = "PVO-V-POS-5--VSOCOORDS-12SEC-V1.0" OBJECT = DATASETINFO DATA_SET_NAME = "PVO VENUS SC POSITION DERIVED VSO COORDS 12 SECOND VER1.0" DATA_SET_COLLECTION_MEMBER_FLG = N START_TIME = 1978-12-05T07:20:07.282 STOP_TIME = 1992-10-08T16:30:37.204 NATIVE_START_TIME = UNK NATIVE_STOP_TIME = UNK DATA_OBJECT_TYPE = "TIME SERIES" DATA_SET_RELEASE_DATE = 1993-09-01 PROCESSING_LEVEL_ID = 5 PRODUCER_FULL_NAME = "MURIEL KNIFFIN" PRODUCER_INSTITUTION_NAME = UCLA SOFTWARE_FLAG = Y DETAILED_CATALOG_FLAG = N PROCESSING_START_TIME = 1991-11-06 PROCESSING_STOP_TIME = 1993-03-30 DATA_SET_DESC = " This dataset contains Pioneer Venus Orbiter (PVO) spacecraft position and orientation data in Venus Solar Orbital (VSO) coordinates. This dataset is sampled every 12 seconds near periapsis, and at 1 minute or 10 minute rates in the solar wind, the lowest rates near apoapsis. Planetocentric and heliocentric position vectors and solar zenith angle (Sun-Venus-PVO) are also provided. The VSO parameters are derived from the PVO Supplemental Experimenter Data Records (SEDR), other parameters are taken directly from the SEDR dataset. Dataset Contents column description unit -------------------------------------------------------- Time: Seconds since 1966-01-01T00:00:00 second X VSO: VSO-X coordinate of PVO (Rv=6050 km) Rv Y VSO: VSO-Y coordinate of PVO (Rv=6050 km) Rv Z VSO: VSO-Z coordinate of PVO (Rv=6050 km) Rv Altitude: Venus Center to PVO Range minus 6050 km km SZA: Solar zenith angle degree PLONG: Planetocentric longitude degree PLAT: Planetocentric latitude degree SPX VSO: PVO spin axis X component in VSO coords N/A SPY VSO: PVO spin axis Y component in VSO coords N/A SPZ VSO: PVO spin axis Z component in VSO coords N/A CLAT: Heliocentric celestial latitude degree CLONG: Heliocentric celestial longitude degree ELONG: Earth's heliocentric celestial longitude degree RSUN: Sun - PVO range 1 A.U. = 149,674,000 km AU This dataset is used by the program PVROT to transform magnetic field vectors from Inertial Spacecraft Coordinates (ISC) to VSO Coordinates. Please refer to the coordinate system template for definitions of these two coordinate systems." CONFIDENCE_LEVEL_NOTE = "This dataset contains parameters which are either taken directly from the Supplemental Experimenter Data Records (SEDR) or are derived entirely from those parameters. The SEDR does contain some gaps, spurious values, and other problems which may cause some data values to be untrustworthy." END_OBJECT = DATASETINFO OBJECT = DATASETTARG TARGET_NAME = VENUS END_OBJECT = DATASETTARG OBJECT = DSPARMINFO SAMPLING_PARAMETER_NAME = TIME SAMPLING_PARAMETER_RESOLUTION = "N/A" MINIMUM_SAMPLING_PARAMETER = "N/A" MAXIMUM_SAMPLING_PARAMETER = "N/A" SAMPLING_PARAMETER_INTERVAL = 12 MINIMUM_AVAILABLE_SAMPLING_INT = 12 SAMPLING_PARAMETER_UNIT = SECOND DATA_SET_PARAMETER_NAME = "POSITION VECTOR" NOISE_LEVEL = "N/A" DATA_SET_PARAMETER_UNIT = "N/A" END_OBJECT = DSPARMINFO OBJECT = SCDSHOST INSTRUMENT_HOST_ID = PVO INSTRUMENT_ID = POS END_OBJECT = SCDSHOST OBJECT = DSREFINFO REFERENCE_KEY_ID = "PC-456.O4" OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "DATA USER REQUIREMENTS" JOURNAL_NAME = "PIONEER VENUS PROJECT SPECIFICATION PC-456.O4" PUBLICATION_DATE = 1976-05-15 REFERENCE_DESC = " NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Ames Research Center Moffett Field, California PIONEER VENUS PROJECT SPECIFICATION PC-456.O4 PIONEER VENUS: DATA USER REQUIREMENTS FOR SUPPLEMENTARY EXPERIMENTER DATA RECORDS May 15, 1976" OBJECT = REFAUTHORS AUTHOR_FULL_NAME = "N/A" END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO END_OBJECT = SCDATASET /*============================================================================*/ /***************Data Set Processing Template***********************************/ /* MODIFICATIONS /* 930224 -- MKNIFFIN /*============================================================================*/ /* product_data_set_id */ /* Last changes made /* Template: Data Set Processing Template Rev: 19890121 */ /* */ /* Note: This template shall be repeated for each */ /* source dataset id used in production of the */ /* dataset id in the dataset template. */ /* */ /* Hierarchy: DSPROCESSING */ OBJECT = DSPROCESSING SOURCE_DATA_SET_ID = "N/A" SOFTWARE_NAME = "PVMOV" PRODUCT_DATA_SET_ID = "PVO-V-POS-5--VSOCOORDS-12SEC-V1.0" END_OBJECT = DSPROCESSING /******************************************************************************/ /* Template: Data Set Processing Template Rev: 19890121 */ /* */ /* Note: This template shall be repeated for each */ /* source dataset id used in production of the */ /* dataset id in the dataset template. */ /* */ /* Hierarchy: DSPROCESSING */ OBJECT = DSPROCESSING SOURCE_DATA_SET_ID = "N/A" SOFTWARE_NAME = "PVO" PRODUCT_DATA_SET_ID ="PVO-V-POS-5--VSOCOORDS-12SEC-V1.0" END_OBJECT = DSPROCESSING /*============================================================================*/ /********************** PARAMETER CATALOG TEMPLATE ****************************/ /* Template: Parameter Template Rev: 19890121 */ /* Note: This template shall be completed for each combination */ /* of data set parameter name, instrument parameter */ /* name and instrument host id associated with a dataset. */ /* Hierarchy: PARAMETER */ OBJECT = PARAMETER INSTRUMENT_HOST_ID = PVO DATA_SET_PARAMETER_NAME = "POSITION VECTOR" INSTRUMENT_PARAMETER_NAME = "POSITION VECTOR" IMPORTANT_INSTRUMENT_PARMS = 1 END_OBJECT = PARAMETER /*************** DATASET INSTRUMENT PARAMETER DESCRIPTION TEMPLATE ************/ /* Template: Data Set Instrument Parameter Description Template Rev: 19890121 */ /* Note: This template shall be completed for any */ /* data set or instrument parameter description. */ /* Hierarchy: DSINSTPARMD */ OBJECT = DSINSTPARMD DATA_SET_OR_INSTRUMENT_PARM_NM = "POSITION VECTOR" DATA_SET_OR_INST_PARM_DESC = "A position vector is a triad which describes the location of a point in 3-space relative to some origin." END_OBJECT = DSINSTPARMD