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Availability: Archived at NSSDC, accessible from elsewhere


This description was generated automatically using input from the Planetary Data System. Overview: ========= This data set contains data from the Plasma Science instrument (PLS) onboard the Galileo spacecraft during the Jupiter orbital operations phase (December 1995 to end of mission). These data have been edited and reformatted from the raw telemetry packets into a simple ASCII tabular structure to facilitate processing and analysis. Parameters: =========== This data set includes both high time resolution (LPW) data recorded during targeted encounters and real-time science (RTS) data acquired during the magnetospheric survey when telemetry was available. The Plasma instrument can collect either RTS data or LPW data but not both simultaneously. The basic data set parameters are the detector count rates in units of counts per second. Data are provided at the full instrument sampling rate in all sampling parameters (time, detector, E/Q, M/Q). The instrument has twenty (20) detectors (seven ion, seven electron, six mass spectrometer) and can sample E/Q or M/Q (mass spectrometer detectors only) in sixty-four (64) steps for each detector. Processing: =========== The final instrument packet files (IPF's) have been processed to decommutate the PLS telemetry into individual instrument modes. Each mode generally covers one spacecraft rotation and contains a number of energy spectra (or mass spectra) at a number of angles. In LPW mode an instrument cycle spans an interval of 4 RIM's (242.67 seconds). During this interval the instrument collects approximately 28 individual modes of data. In RTS operation the cycle is different, and longer, due to the severely reduced telemetry rates. The energies, accumulation times, and sectoring schemes all vary from mode to mode, as with the LPW data. A major accomplishment of the RDR processing is to recast the PLS data in a format that is independent of the details of the operating modes. The resulting RDR data records are much easier to use. The PLS telemetry system is sensitive to data gaps. Repairing data due to embedded data gaps cannot be automated. Consequently measurements with gaps in the middle of an individual modes are not included in the RDR file. Fortunately, such gaps occurred infrequently. The recovery of LPW data was generally good. Multiple playbacks were made on each LPW recording to fill gaps. Please refer to the calibration document (CALIB.TXT) contained on the PDS archive volume for a discussion of pitfalls and problems in using the RDR files. This document is located on the PDS archive volumes in the DOCUMENT/PLS directory. Ancillary Data: =============== Several ancillary files are provided with these data: calibration tables, a calibration document, and a spacecraft events file. Calibration: PLSCALIB.TXT Describes the calibration algorithm and pitfalls. PLS_DETS.TAB maps detector numbers to detector names/functions E_STEP_1.TAB E-steps for electron detectors 14,16,18, and 20. E_STEP_2.TAB E-steps for ion dets 3,5,9,11 and mass spec dets 6,7 E_STEP_3.TAB E-steps for electron detectors 15,17, and 19. E_STEP_4.TAB E-steps for ion dets 4,8,10 and mass spec dets 1,2,12,13 M_STEP_1.TAB M-steps for the mass spectrometer channels SECTOR.TAB AACS sector angles CALIB_1.TAB Calibration factors to convert count rates to differential flux for electron detectors 14,16,18, and 20 CALIB_2.TAB Calibration factors to convert count rates to differential flux for ion detectors 3,5,9,11 and mass spec detectors 6 and 7. CALIB_3.TAB Calibration factors to convert count rates to differential flux for electron detectors 15,17, and 19. CALIB_4.TAB Calibration factors to convert count rates to differential flux for ion detectors 4,8,10 and mass spec detectors 1,2,12 and 13. Spacecraft Events: xxx_SEF.TXT A time ordered file extracted from the As-Run Spacecraft Events Files (ARSEF) that provides the timing of events that are significant to the plasma experiment. These events include whether or not the instrument is 'on', which type of data are being acquired (RTS or LPW), the time of thruster firings, etc. The 'xxx' in the file name is the orbit name (i.e. G01 for orbit Ganymede 1). Coordinate System: ================== Data are provided in PLS instrument coordinates. Please refer to the instrument description paper [FRANKETAL1992] for a description of the instrument mounting, detector fields of view, and spin phase sectoring. See also the SECTOR.TAB file in the ancillary data files. Software: ========= There is no software provided with this archive. Media/Format: ============= These data are archived on either CDROM or DVDROM media. The data files are stored in a simple ASCII table form that is described by a detached PDS label (Table Object). Each table has the following structure: Col# Name Format Description ----------------------------------------------------------------------1 Time A24 Spacecraft event time (UTC) 2 SCLK A11 Spacecraft clock counter (RIM:mf) 3 Rate 1PE8.2 Count rate (counts/sec) 4 DetId I2 Detector Id (1-20) 5 E-Step I2 E/Q analyzer step (0-63) 6 M-Step I2 M/Q analyzer step (0-63) 7 Sector I3 AACS rotor spin angle (0-255 =2 PI). 8 Sample I2 Sample number 9 Accum F6.4 Accumulation time in seconds

Alternate Names



  • Planetary Science: Fields and Particles

Additional Information



Questions and comments about this data collection can be directed to: Dr. Edwin V. Bell, II



NameRoleOriginal AffiliationE-mail
Dr. Kent L. AckersonData ProviderUniversity of
Dr. Kent L. AckersonGeneral ContactUniversity of
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