Data Set Information
DATA_SET_NAME P11 FLUXGATE MAGMETOMETER 5 MINUTE JUPITER SUMMARY DATA
DATA_SET_ID P11-J-FGM-4-SUMM-5MIN-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview ================= This data set consists of magnetic field vector data recorded by the Fluxgate Magnetometer onboard the Pioneer 11 spacecraft, during the Jupiter encounter period. Data include 5 minute averages of the magnetic field in both Inertial Heliocentric and System III (1957.0) coordinates. Spacecraft trajectory data are also provided, in System I and System III (1957.0) coordinates. Data Sampling ============== The fluxgate magnetometer data is multiplexed into one of the Science Subcom formats available on the spacecraft. Two separate 6-bit words per subcom cycle are assigned to the instrument and thus 3 complete cycles are required to read out the contents of the output buff. At a bit rate of 2048 bps, a complete subcom cycle requires 6 second and a vector measurement is obtained approximately every 18 to 24 second depending on the actual roll rate of the spacecraft, which is nominally 5 revolutions per minute (ACUNA&NESS1974). The NSSDC documentation does not contain information about what data resolution this data set (5 minute) is averaged from. Data Processing =============== No detailed information of data processing is found in the NSSDC documentation pertinent to this data set. Pioneer 11 spacecraft was operating under a spin-stablized condition and had a spin period of 12 seconds. Data Format ============ The Pioneer 11 magnetometer data for Jupiter encounter were originally written on a BCD magnetic tape created at NSSDC from a card deck supplied by the PI team. The original file was re-formatted into a new ASCII file named P11_FGM_JUP_ENC_5MIN.TAB which contains the following data columns: -------------------------------------------------------------------- Column Column Column Name Format Description -------------------------------------------------------------------- TIME A24 Ground received time in yyyy-mm-ddThh:mm:ss.sssZ R F5.2 Distance of Pioneer 11 from Jupiter in Rj LAT F6.1 Latitude of Pioneer 11 in System III (1957.0) LON1 F7.1 Longitude of Pioneer 11 in System I LON3 F7.1 Longitude of Pioneer 11 in System III (1957.0) BX F8.4 X component of the magnetic field in Inertial Heliocentric coordinates BY F8.4 Y component of the magnetic field in Inertial Heliocentric coordinates Bz F8.4 Z component of the magnetic field in Inertial Heliocentric coordinates BR F8.4 Radial component of the magnetic field in System III (1957.0) BTHETA F8.4 Polar component of the magnetic field in System III (1957.0) BPHI F8.4 Azimuthal component of the magnetic field in System III (1957.0) N I2 Number of data points used in averaging -------------------------------------------------------------------- Coordinate System for Data =========================== System I is a planetographic spherical coordinates at Jupiter. This system used a relatively faster Jupiter spin rate (877.90 degree per 24 hours) to describe cloud features within 10 degree of the equator. The Central Meridian Longitude was established at 12:00 Greenwich Mean Time on July 14, 1897. System III (1957.0) is a planetographic spherical coordinates. In this system, the Jovian rotation period is defined to be 9h55m29.37s and the Central Meridian Longitude is defined at 00:00 UT on January 1, 1957. Inertial Heliocentric coordinates is a Cartesian system, defined based on two principle directions, the Jupiter spin axis J, and the direction from the sun to the first point of Aries, X. The Y direction is given by the cross product of J and X. The Z direction is defined as the cross product of X and Y. Ancillary Data ============== There is no ancillary data associated with this data set. Instrument Calibration ====================== The fluxgate magnetometer was calibrated at the GSFC Magnetic Test Facility by means of a 2 meter diameter, single axis Helmholtz coil system. Typically hysteresis observed after exposure to 2.5 mT fields was less than 1 part in 10**3 (one count). Temperature stability is better than +- 0.5% over the temperature range of -20 to +40 degree Celsius in spite of the open loop design of the instrument. This is due to the fact that the characteristics of the magnetic material used in the sensor cores are fairly independent of temperature over the indicated range. The stability figure includes the A/D converter drift and a large portion of it is due to the single ramp design of the latter. Nevertheless, minimum power consumption requirements and flight qualified component availability precluded the used of more stable A/D converter designs (ACUNA&NESS1974).
DATA_SET_RELEASE_DATE 3000-01-01T00:00:00.000Z
START_TIME 1974-12-02T11:31:40.000Z
STOP_TIME 1974-12-03T11:12:16.000Z
MISSION_NAME PIONEER 11
MISSION_START_DATE 1972-03-02T12:00:00.000Z
MISSION_STOP_DATE 1995-09-30T12:00:00.000Z
TARGET_NAME JUPITER
TARGET_TYPE PLANET
INSTRUMENT_HOST_ID P11
INSTRUMENT_NAME MAGNETOMETER
VECTOR HELIUM/FLUXGATE MAGNETOMETERS
FLUXGATE MAGNETOMETER
INSTRUMENT_ID FGM
INSTRUMENT_TYPE MAGNETOMETER
NODE_NAME planetary plasma interactions
ARCHIVE_STATUS SUPERSEDED
CONFIDENCE_LEVEL_NOTE Confidence Level Overview ========================= No data confidence information is found in the NSSDC documentation pertinent to this data set. There is no flagged values in this data set.
CITATION_DESCRIPTION N/A
ABSTRACT_TEXT Pioneer 11 Fluxgate Magnetometer (FGM) data from the Jupiter encounterperiod between 1974-12-02T23:31:40.000 and 1974-12-03T11:12:16.000.The data set provides 5 minute magnetic field averages in both InertialHeliocentric and System III (1957.0) coordinates, and spacecrafttrajectory data in System I and System III (1957.0) coordinates.
PRODUCER_FULL_NAME Mario H. Acuna
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