Data Set Information
DATA_SET_NAME MAGELLAN SOLAR CORONA AND FARADAY ROTATION V1.0
DATA_SET_ID MGN-SS-RSS-1-ODR-OPENLOOP-SW-SCINT-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview ================= This data set contains raw and partially processed data from observations of Magellan radio transmissions while the signal was passing through the solar corona. Scintillations on the signal can be related to structure and motion of the coronal material [WOO1993]; polarization of the signal can be used to infer magnetic field within the plasma. Data were acquired using stations of the NASA Deep Space Network (DSN). The Magellan spacecraft transmitted signals that were 100 percent linearly polarized at 13 cm and right-elliptically polarized at 3.6 cm. During summer 1992, when Magellan was in solar superior conjunction, the spacecraft came within 0.6 solar radii of the Sun's center when viewed from Earth. Included in this data set are over 1000 files of raw samples acquired using DSN open-loop receivers and recorders, often in two orthogonal circular polarizations at both wavelengths. The data set spans several months, centered on the superior conjunction date of 1992-06-13. Parameters ========== Each open-loop data file (data type ODR) contains a header followed by several thousand 8-bit sample values from 1-4 receiver output channels. The header gives the time of the first sample, the antenna through which the data were collected, channel assignments, the local oscillator frequency of the receiver, rms values of each receiver output, status and condition flags, and other data useful for interpreting the receiver samples. The samples were obtained coherently from one or more of the following receiving systems: X-RCP 3.6-cm right circularly polarized S-RCP 13-cm right circularly polarized X-LCP 3.6-cm left circularly polarized S-LCP 13-cm left circularly polarized Each 8-bit sample represents the band-limited voltage output of one of the receivers above; individual samples were written to the data file, usually in the order given above. Samples could be collected at rates varying from 100 to 50000 per second from each receiver. The number of samples in each record varied depending on the sampling rate and number of channels being collected. Processing ========== Samples from parallel analog-to-digital converters were stored in buffers until the correct number had been accumulated. Header information was accumulated separately. When the sample buffer was filled, the samples were combined with the header data and the record was written to tape. RMS values of receiver outputs were included in the header. There was no other processing of the data. Data ==== ODR files have names of the form ydddhhmm.ODR where y is the least significant digit of the year, ddd is the 3-digit day- of-year, hh is the hour, and mm is the minute on which data acquisition began. Each ODR file is accompanied by a detached PDS label with name ydddhhmm.LBL. Each label fully describes the format and content of the corresponding data file. There are 1035 ODR files in this data set. Ancillary Data ============== None. Coordinate System ================= Not applicable. Software ======== Software for parsing, reducing, and analyzing data such as these has been developed at the Jet Propulsion Laboratory, Stanford University, and elsewhere. Because parsing must be done at the bit level, its implementation may be very sensitive to platform and operating system. No parsing software has been written and tested on a variety of platforms, so none has been included with the archival data set. Users are referred to PDS labels for detailed information on file formats. Media/Format ============ The archival data set is written on DVD-R media. Each DVD-R volume conforms to ISO 9660 standards.
DATA_SET_RELEASE_DATE 1998-12-31T00:00:00.000Z
START_TIME 1992-01-17T09:02:08.000Z
STOP_TIME 1992-08-14T06:30:39.500Z
MISSION_NAME MAGELLAN
MISSION_START_DATE 1989-05-04T12:00:00.000Z
MISSION_STOP_DATE 1994-10-12T12:00:00.000Z
TARGET_NAME SUN
TARGET_TYPE SUN
INSTRUMENT_HOST_ID MGN
INSTRUMENT_NAME RADIO SCIENCE SUBSYSTEM
GRAVITY SCIENCE INSTRUMENT
INSTRUMENT_ID RSS
INSTRUMENT_TYPE RADIO SCIENCE
NODE_NAME planetary plasma interactions
ARCHIVE_STATUS ARCHIVED
CONFIDENCE_LEVEL_NOTE Overview ======== This collection of 1035 ODR data files spans the time period from 1992/017-09:02:00 through 1992/227-06:31:00. Solar conjunction was on 1992/165. Review ====== This archival data set was distributed for peer review prior to its acceptance by the Planetary Data System (PDS). The review was conducted in accordance with PDS procedures. Prior to creation of the final version of the archival data set, the archive was distributed on CD-WO volumes for preliminary review. These included data files, PDS labels, and most documentation. Data Coverage and Quality ========================= The data extend from five months before the 1992 Magellan solar superior conjunction (1992-06-13) to two months after. Data quality is highly variable with the best data collected using 70-m DSN antennas closest to solar conjunction. Data most useful for Faraday Rotation analysis were collected at S- and X-band using dual orthogonally polarized antennas. This configuration is only possible when using 70-m DSN antennas. The following table shows dates, times, and antennas when 70-m antennas were used close to solar conjunction. Year/Day-of-Year Antenna Start Time (UTC) Stop Time (UTC) ---------------- ------- ---------------- --------------- 1992/158 43 02:30 03:39 1992/158 43 04:01 05:55 1992/162 14 13:30 15:11 1992/162 14 15:35 17:30 1992/164 63 12:53 17:53 1992/164 63 17:53 18:50 1992/164 14 19:14 19:33 1992/164 14 19:44 22:35 1992/166 63 05:42 07:11 1992/166 63 07:28 15:30 1992/168 63 05:34 09:46 1992/173 14 13:58 15:09 1992/173 14 15:35 16:30 Approximately one file in every 15 has at least one header record with an unexpected (or empty) field. Location of these anomalous records varied but included fields where date, time, or spacecraft number was expected. Limitations =========== Some or all of the observations recorded in this data set may have been collected while the spacecraft radio system was in two-way tracking mode. That is, the signal frequency transmitted by the spacecraft was referenced to the frequency of a signal it received simultaneously from the ground. For interpretation, the effects of the solar plasma must be considered on both the 'uplink' and 'downlink' portions of the path. During some observations, the reference signal transmitted from the ground may have been 'ramped' -- that is, the frequency of the 'uplink' signal was a linear function of time. Coefficients of the linear function are saved in the Archival Tracking Data File, but those files are not included in this archive.
CITATION_DESCRIPTION , MAGELLAN SOLAR CORONA AND FARADAY ROTATION V1.0, MGN-SS-RSS-1-ODR-OPENLOOP-SW-SCINT-V1.0, NASA Planetary Data System, 1998.
ABSTRACT_TEXT This data set contains raw and partially processed data from observations of Magellan radio transmissions while the signal was passing through the solar corona. Scintillations on the signal can be related to structure and motion of the coronal material [WOO1993]; polarization of the signal can be used to infer magnetic field within the plasma. Data were acquired using stations of the NASA Deep Space Network (DSN). The Magellan spacecraft transmitted signals that were 100 percent linearly polarized at 13 cm and right-elliptically polarized at 3.6 cm. During summer 1992, when Magellan was in solar superior conjunction, the spacecraft came within 0.6 solar radii of the Sun's center when viewed from Earth.
PRODUCER_FULL_NAME PLANETARY DATA SYSTEM PLANETARY PLASMA INTERACTIONS NODE
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