Galileo PLS Jupiter Calibrated Bundle Galileo PLS Jupiter Averaged Plasma Counts Calibrated Collection PDS3 DATA_SET_ID = GO-J-PLS-4-SUMM-AVG-COUNTS-V1.0 PDS3 DATA_SET_NAME = GALILEO JUPITER AVERAGED PLASMA COUNTS V1.0 START_TIME = 1995-12-07T15:30 STOP_TIME = 2003-09-21T18:45 PDS3 DATA_SET_RELEASE_DATE = 2003-11-21 PRODUCER_FULL_NAME = XIANZHE JIA References: Frank, L.A., Paterson, W.R., Ackerson, K.L., GALILEO JUPITER AVERAGED PLASMA COUNTS V1.0, GO-J-PLS-4-SUMM-AVG-COUNTS-V1.0, NASA Planetary Data System, 2008. Overview: ========= This collection contains raw 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, averaged, and reformatted from the raw telemetry packets into a simple ASCII tabular structure to display and analysis. Parameters: =========== This collection includes high time resolution (LPW) data recorded during targeted encounters Galileo moon encounters and selected magnetospheric survey itenrvals when telemetry was available. 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: =========== These data have been averaged from the PLS uncalibrated full- resolution data set (PDS3 DATA_SET_ID = GO-J-PLS-3-RDR-FULLRES-V1.0). Please refer to the data set catalog file for a full description of the processing performed on that data set. The following is a description of the averaging performed on this data set. The uncalibrated counts have been averaged over all detectors available at each time step. The time is located at the center of the interval. In order to remove data gaps between the detectors, each energy channel has been fitted and with a cubic spline. To smooth the data over timesteps, a simple two point running average was used over all 64 energy channels in time. Finally, to smooth the data, an average was performed over a square consisting of nine unweighted points with the original data point being at the center of the square. For simplicity, and due to the similar values across the detectors in the E_STEP tables, only the values used in E_STEP_2.TAB were used in the plotting and ascii tables. Ancillary Data: =============== Spacecraft Events: 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). Software: ========= There is no software provided with this archive. Media/Format: ============= 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 UTC A21 Spacecraft event time (UTC) at the average center 2-65 Counts e10.2 Average count rates at 64 energy steps 66-129 Energy e10.2 Energy for count rate channel of same array index" Data Coverage/Quality: ====================== The data are not continuous in time. High resolution data were available for only short intervals of about an hour each orbit. The PLS instrument has two analyzers: A and B. Each analyzer has its own sensors, high voltage supplies, analyzer plates, and data paths. The two analyzers normally start a spin-mode at the same time. And they normally end a spin-mode at the same time. Both data streams are buffered internally by the PLS data system and sent out to the spacecraft in a packetized telemetry scheme. Generally, the two streams are interleaved on a minor-frame-by-minor-frame basis, but if one analyzer does not have data ready and the other does then the telemetry that is ready is sent. (Note that the two analyzers have different numbers of sensors and create different quantities of data.) On the ground, the PLS telemetry stream is decommutated and separated into A and B data-sets for each spin-mode. The time tag attached to each A-data-set and each B-data-set is the time of the first telemetry packet containing some of that data. As soon as a complete collection has been decommutated on the ground it is written to the output file. And this is the key to understanding what is happening. Sometimes the first data-set to appear in the telemetry stream is also the first one to be completed. And sometimes the first data-set to appear in the telemetry is the last to be completed. It is essentially a random thing. It is crucial to note that PLS takes all of its data in a spin- synchronized fashion, not in a SCLK-synchronized fashion. We went to great pains to ensure that the data were obtained in well-defined spin sectors and in repeatable directions. Differences of a couple of minor-frames are not significant. The spin-phase angles are the quantities of importance.