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 |
The Cassini INMS Science Packet data set contains all telemetry
packets as received from the instrument. Each packet is stored in
a standard data product with one record per packet. Items are
converted from DN to dimensional values.
|
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
SATELLITE
SATELLITE
PLANET
SATELLITE
SATELLITE
SATELLITE
SATELLITE
SATELLITE
SATELLITE
|
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
|
SEARCH/ACCESS DATA |
Planetary Plasma Interactions Website
|
|