Data Set Information
DATA_SET_NAME CASSINI S INMS TELEMETRY PACKET DATA V1.0
DATA_SET_ID CO-S-INMS-2-PKT-U-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION DATA SET OVERVIEW ================= The Cassini Ion and Neutral Mass Spectrometer (INMS) Packet data set contains all telemetry packets as received from the instrument. One standard product data type is defined for each INMS telemetry Packet. In each standard data product. one record is produced for each packet. Each item in the packet is converted from data numbers to dimensional values. The data set contains all science packets for the entire Cassini mission. The data set includes telemetry data from the instrument checkout periods, SOI and the entire Saturn tour.Each standard data product is organized as a spread sheet with one row for each packet. Each column in the spread sheet contains the contents of one item in the telemetry packet, converted from data number to dimensional quantities where appropriate. PARAMETERS ========== The INMS Packet data set includes five standard data product types, outlined in the table below. The first four data products contain the telemetry packets converted to dimensional quantities and are produced at a cadence of one record per telemetry packet. The contents of each standard data product type are described more fully below: Standard Data Contents Data Rate Product Type INMS_SCI Science(SCI) Packets Variable INMS_HKG Housekeeping (HKG) Packets 68 s INMS_HMD HKG Memory Dump Packets 68 s INMS_SMD SCO Memory Dump Packets Variable INMS_OTS Operational Table Sets Not Applicable INMS_SCI -------- The Science Packet data product includes one record per instrument integration period. The integration period, at full telemetry rate, is 31 ms with samples collected at a 34 ms cadence. When telemetry bandwidth is limited, measurements are accumulated by the instrument software prior to construction of the telemetry packet. In this case the integration period is equal to the number of measurements accumulated to form the telemetry packet times the basic 31 ms integration period. Parameters in the file include packet identification, instrument state and status, and 68 counter values for the low and high sensitivity counters. INMS_HKG -------- The Housekeeping Packet Data product includes one record per housekeeping packet. The housekeeping packets are produced at a 68 second cadence. Parameters in the file include packet identification, instrument state and status. Housekeeping packets are not produced when a housekeeping memory dump is in progress. INMS_HMD -------- The Housekeeping Memory Dump product contains memory dump information and is produced only for those time periods during which a memory dump through the housekeeping telemetry was in progress. Housekeeping data packets are produced on a 68 second cadence Parameters in the file include packet identification, instrument state and status, and 32 words of memory image. INMS_SMD -------- The Science Memory Dump product contains memory dump information and is produced only for those time periods during which a memory dump through the science telemetry was in progress. Science memory dump packets are produced at a rate which depends on the data rate asigned to the INMS instrument. Parameters in the file include packet identification, instrument state and status, and 171 words of memory image. PROCESSING ========== The data in this data set is minimally processed. Instrument state information is converted from data numbers to dimensional quantities by applying calibration constants. COORDINATE SYSTEM ================= Not Applicable SOFTWARE ======== MEDIA FORMAT ============ The data are archived on either CDROM or DVDROM media. The data files are stored in a comma-separated ASCII spreadsheet form that is described in the detached PDS label (Spreadsheet Object). The structure of the spreadsheet is specified in the format file included, by pointer, in the PDS label.
DATA_SET_RELEASE_DATE 2018-07-03T00:00:00.000Z
START_TIME 2004-01-01T12:00:00.000Z
STOP_TIME 2017-09-15T11:59:59.000Z
MISSION_NAME CASSINI-HUYGENS
MISSION_START_DATE 1997-10-15T12:00:00.000Z
MISSION_STOP_DATE 2017-09-15T12:00:00.000Z
TARGET_NAME DIONE
RHEA
TETHYS
SATURN
ENCELADUS
HYPERION
MIMAS
IAPETUS
TITAN
PHOEBE
TARGET_TYPE SATELLITE
PLANET
INSTRUMENT_HOST_ID CO
INSTRUMENT_NAME ION AND NEUTRAL MASS SPECTROMETER
INSTRUMENT_ID INMS
INSTRUMENT_TYPE QUADRAPOLE MASS SPECTROMETER
NODE_NAME planetary plasma interactions
ARCHIVE_STATUS LOCALLY ARCHIVED
CONFIDENCE_LEVEL_NOTE CONFIDENCE LEVEL OVERVIEW ========================= This data set contains all of the telemetry packets produced by the Cassini INMS instrument for the intervals described in the labels of the individual data files. REVIEW ====== The INMS Packet data set will be reviewed internally by the Cassini INMS team prior to release to the PDS. The data set will also undergo a PDS peer review prior to release. DATA COVERAGE AND QUALITY ========================= PRIOR TO SOI ------------ Prior to SOI the INMS instrument was evacuated and the aperture was closed by a cover installed prior to launch. The instrument was operated during in-flight check-outs (ICO) collecting baseline calibration data. During the approach science phase, INMS was operated nearly continuously to obtain operational experience and to validated data collection tables. Data is available for the following periods: ICO-1 1999-005 1999-006 1999-009 1999-010 1999-021 ICO-2 none Approach 2003-226 through 2003-230 2003-315 2003-321 through 2003-328 2004-011 through 2004-018 2004-058 through 2004-060 2004-064 through 2004-071 2004-092 through 2004-131 2004-135 through 2004-163 2004-171 through 2004-174 The INMS cover was jettisoned immediately following SOI, permitting measurements of the ion and neutral constituents. POST SOI -------- INMS science data collection began at SOI. From SOI onwards, the instrument was essentially in continuous operation. An issue with velocity compensation exists from launch through 2005-058 which results in differences between the flight software computed quad lens bias voltages and ground computed values for the same velocity. This issue results in signal level changes when switching between velocity compensated scans and energy scans with ground computed quad lens voltages. The issue is resolved in data collected after TBS-DATE by correcting the ground computation of lens bias voltages. Prior to 2005-058 the flight software velocity compensation algorithm clipped only the lens voltage that reached its limit, allowing the other three voltages to be adjusted. This resulted in the voltages failing to maintain their proper relation- ships. This was corrected by insuring that once one voltage reached its limit, all four voltages were frozen. The spacecraft background command sequence was halted on 2004-185 and it was resumed on 2004-194. During this period, housekeeping data was produced on all days but day 2004-191. During the period from 2005-007 through 2005-014, the instrument was shut down while the Probe mission occurred. No packet data was produced during this period. During the period from 2005-015 through 2005-021, only realtime housekeeping data was produced, no SCI packets were recorded on board while waiting for the Probe mission data to be validated. During S31 (from 2007-182), S32, S33, and S34 (to 2007-273) data gaps of more than one day occurred on days 255, 256, and 257 resulting in the PKT file being absent from the data for those days. These gaps were the result of spacecraft safing. During S48 (from 2009-091), S49, S50, S51 (to 2009-181) data gaps of more than one day occurred on day 124 resulting in the PKT file being absent from the data for those days. These gaps were the result of a Deep Space Network station breakdown. During S56 (from 2010-001), S57, S58 (to 2010-090) data gaps of more than one day occurred on days 003, 004, and 005 resulting in the PKT file being absent from the data for those days. These gaps were the result of the instrument being turned Off because of an SSPS Trip on the spacecraft. During S63 (from 2010-274), S64, S65 (to 2010-365) data gaps of more than one day occurred on days 307-318 resulting in the PKT file being absent from the data for those days. These gaps were the result of the instrument being turned Off because of a spacecraft safing event. During S75, data gaps of more than one day occurred on days 2013-294 through 2013-302 resulting in the PKT file being absent from the data for those days. These gaps were the result of the instrument being turned off during the Cassini Propellant Gauge Test. During S83 (from 2014-091) and S84 (to 2014-181) a data gap of more than one day occurred on day 128 resulting in the PKT file being absent from the data for that day. This gap was the result of telemetry gaps. During S92 (from 2016-001), the data gap on day 021 was a result of an end of mission downlink test which resulted in the PKT file being absent from the data for that day. During S101 (from 2017-191), the data gap on day 208, 209, and 231 were the result of putting the instrument to sleep for table loads for the final proximal orbits. No data is available past 2017-258, as the mission ended by flying the Cassini spacecraft into Saturn. LIMITATIONS =========== During the period from launch through 2004-256, a flight software error caused data corruption when mass scans were accumulated to reduce data rates. These data are identified by a value of the COADD_CNT greater than 1. Prior to 2005-058 the flight software velocity compensation algorithm clipped only the lens voltage that reached its limit, allowing the other three voltages to be adjusted. This resulted in the voltages failing to maintain their proper relation- ships. This was corrected by insuring that once one voltage reached its limit, all four voltages were frozen. The Earth Received Time (TERTTIME) and the Processed Time (TPROCESSEDTIME) are reversed in the HKG data in version 5 files (and earlier versions). This has been corrected in version 6 files.
CITATION_DESCRIPTION Gell, D.,A., CO-S-INMS-2-PKT-U-V1.0, CASSINI S INMS TELEMETRY PACKET DATA V1.0, NASA Planetary Data System, 2018.
ABSTRACT_TEXT The Cassini Ion and Neutral Mass Spectrometer (INMS) Packet data set contains all telemetry packets as received from the instrument. One standard product data type is defined for each INMS telemetry Packet. In each standard data product. one record is produced for each packet. Each item in the packet is converted from data numbers to dimensional values. The data set contains all science packets for the entire Cassini mission. The data set includes telemetry data from the instrument checkout periods, SOI and the entire Saturn tour.Each standard data product is organized as a spread sheet with one row for each packet. Each column in the spread sheet contains the contents of one item in the telemetry packet, converted from data number to dimensional quantities where appropriate.
PRODUCER_FULL_NAME DR. DAVID A. GELL
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