| CONFIDENCE_LEVEL_NOTE |
CONFIDENCE LEVEL OVERVIEW
=========================
This data set contains all of the counter data for the Cassini
INMS instrument for the intervals described in the labels of the
individual data files.
REVIEW
======
The INMS L1A complete 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 validate data collection tables.
The INMS cover was jettisoned immediately after 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. Until a software
patch was installed during S16, the instrument processor would
unexpectedly reset, causing a loss of science data to occur until
the flight software was re-loaded. These occurrences are noted below.
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 relationships.
This was corrected by insuring that once one voltage reached its
limit, all four voltages were frozen.
The spacecraft background sequence was halted just after SOI,
during this period, from day 2004-186 through 2004-194 no L1A
data was produced.
Flight software checkout was performed between 2004-252T19:25:00.044
and 2004-255T19;10:10.044 and as a result no L1A data was
produced.
No L1A data was produced on days 2004-309 and 2004-310 due to an
interrupted flight software load.
During S5, one unexpected processor reset occurred at
2004-310T10:03:45, with a data loss until 2004-311T00:00:00
No L1A data was produced during the Probe mission from 2005-007
through 2005-014 and the period following from 2005-015 through
2005-022 while the solid state recorder was being protected until
the the Probe mission data was validated.
During S10, one unexpected processor reset occurred at
2005-105T17:32:07. No science data was collected from that instant
until the next planned reset at 2005-106T07:00:00.
During S11, three unexpected processor resets occurred at
2005-135T05:10:27, 2005-139T13:15:44 and 2005-148T02:46:22. No
science data was collected from between the unexpected processor
resets and the following planned resets. As a result no science data
was collected from 2005-135T05:10 through 2005-163T23:59:59 except
for short periods following each of the planned resets.
During S15 there was one unexpected processor reset, which occurred
at 2005-289T17:06:55. No science data was collected from between the
unexpected and the planned reset at 2005-300T18:39:00. Another gap
occurred beginning at approximately 2005-309:18:00:00 and extended
until approximately 2005-314T17:00:00. This gap was the result of
data policing by the spacecraft command and data system.
During S16, S17, S18 and S19 there were no unexpected processor
resets. Telemetry gaps of more than 1 file occurred on 2006-006,
007, 036, 037, 044, 045 and 081 resulting in one or more L1A files
being absent from the data for those days.
During S20 and S21 there were no unexpected processor resets.
Data gaps of more than one hour occurred on days 2006-096,
120, 121, 122, 124, 145, 158, 159 162 and 167, resulting in one
or more L1A files being absent from the data for those days. The data
gaps on days 096, 124, 158 and 159 were due to the instrument being
placed in sleep for the orbit trim maneuvers. The remaining were due
to telemetry gaps.
During S22, S23, S24 there were no unexpected process resets. Data
gaps of more than one hour occurred on days 2006-191, 195, 213, 249,
253, 257, 267, resulting in one or more L1A files being absent from the
data for those days. The data gaps on days 213 and 253 were the result
of placing the instrument in sleep mode during orbit trim maneuvers.
The gap on day 257 was due to a software update and a planned
instrument reset. The remaining gaps were due to telemetry gaps.
During S24 (end), S25, S26 (beginning) there were no unexpected
processor resets. Data gaps of more than one hour occurred on days
2006-274, 286, 287, 288, 290, 298, 299, 311, 312, 313, 344, 349, 354,
363, 364, 365, resulting in one or more L1A files being absent from
the data for those days. The data gaps on days 274, 290, 313, 349,
354, and 365 were the result of placing the instrument in sleep mode
during orbit trim maneuvers. The remaining gaps were due to telemetry
gaps.
During S26 (end), S27, S28, S29 (beginning) there were no unexpected
processor resets. Data gaps of more than one hour occurred on days
2007-004, 005, 021, 038, 048, 049, 052, 053, 054, 061, 072, 077, 085,
086, 087, 088, resulting in one or more L1A files being absent from the
data for those days. The data gaps on days 021, 038, 061, 072, 077 and
087 were the result of placing the instrument in sleep mode during
orbit trim maneuvers. The remaining gaps were due to telemetry gaps.
During S29 (end), S30, S31 (beginning) there were no unexpected
processor resets. Data gaps of more than one hour occurred on days
2007-092, 093, 094, 095, 109, 122, 124, 139, 141, 152, 156, 159, 160,
168, 170, 172, 173, resulting in one or more L1A files being absent
from the data for those days. The data gaps on days 109, 124, 141, 152,
156, 168, 172, and 173 were the result of placing the instrument in
sleep mode during orbit trim maneuvers. The remaining gaps were due to
telemetry gaps.
During S31 (from 2007-182), S32, S33, and S34 (to 2007-273) there were
no unexpected processor resets. Data gaps of more than one hour
occurred on days 218, 245, 252, 254, 255, 256, 257, 258, 259, 269, 270,
and 273 resulting in one or more L1A files being absent from the data
for those days. The gaps on days 254 through 259 were the result of
spacecraft safing. The data gaps on days 218 and 245 were the result of
placing the instrument in sleep mode during orbit trim maneuvers. The
remaining gaps were due to telemetry gaps.
During S34 (from 2007-274), S35, and S36 (to 2007-365) there were
no unexpected processor resets. Data gaps of more than one hour
occurred on days 274, 276, 278, 279, 280, 281, 282, 283, 284, 285, 286,
287, 288, 289, 290, 291, 292, 293, 294, 295, 305, 323, 324, 326, 331,
334, 342, 346, 347, 348, 353 and 363 resulting in one or more L1A files
being absent from the data for those days. The gaps on days 279 through
295 were the result of spacecraft flight software activities including
a spacecraft flight software upload. The data gaps on days 305, 326,
331, 342, 353 and 363 were the result of placing the instrument in
sleep mode during orbit trim maneuvers. The remaining gaps were due
to telemetry gaps.
During S36 (from 2008-001), S37, S38, and S39 (to 2008-091) there were
no unexpected processor resets. Data gaps of more than one hour occurred
on days 002, 003, 015, 016, 027, 037, 041, 050, 061, 065, 067, 070, 073,
and 074 resulting in one or more L1A files being absent from the data
for those days. The gap on day 065 was the result of placing
the instrument in sleep mode to allow sufficient data volume
for an MRO. The gaps on days 015, 016, and 027 were the result
of placing the instrument in sleep mode for an RSS experiment
(an orbit trim maneuver followed the RSS experiment on day 016,
so INMS remained in sleep mode until 07:15:15).
The gaps on days 037, 050, 061, 067, 073, and 074 were the result of
placing the instrument in sleep mode during orbit trim maneuvers. The
remaining gaps were due to telemetry gaps.
During S39 (from 2008-092), S40, and S41 (to 2008-182) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 092, 102, 111, 113, 117, 123, 129, 138, 139, 168, and 175 resulting
in one or more L1A files being absent from the data for those days. The
gap from day 138 17:29:28 to day 139 22:45:12, as well as the gaps on
days 092 and 168 were the result of placing the instrument in sleep mode
for an RSS experiment. The gaps on days 102, 117, 138 (00:48:56 to
03:21:13), and 175 were the result of placing the instrument in sleep
mode during orbit trim maneuvers. The remaining gaps were due to
telemetry gaps.
During S41 (from 2008-183), S42, S43, and S44 (to 2008-274)
there were no unexpected processor resets. Data gaps of
more than one hour occurred on days 189, 195, 202, 216,
217, 232, 233, 234, 235, 236, 237, 238, and 264
resulting in one or more L1A files being absent from the data for those
days. The gaps on days 189, 217, 232, 233, 234, 235, and 236 05:49:48 to
238 05:49:47 were the result of placing the instrument in sleep mode.The
gaps on days 216 21:38:17 to 217 00:16:09, 236 02:00:28 to 04:51:08
and 264 were the result of placing the instrument in sleep mode during
orbit trim maneuvers. The remaining gaps were due to telemetry gaps.
During S44 (from 2008-275), S45, S46 (to 2008-366) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 275, 276, 287, 291, 305, 313, 317, 328, 330, 331, 344, 348, 349,
351, 352, 353, and 354 resulting in one or more L1A files being absent
from the data for those days. The gaps on days 276, 287, 291, 313, 317,
328, 344, and 348 were the result of placing the instrument in sleep
mode during orbit trim maneuvers. The remaining gaps were due to
telemetry gaps.
During S46 (from 2009-001), S47, S48, S49 (to 2009-090) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 024, 032, 041, 058, 063, 064, 068, 071, 072, 073, 074, 075, 076,
077, and 088 resulting in one or more L1A files being absent
from the data for those days. The gaps on days 024, 041, 068, and 088,
were the result of placing the instrument in sleep mode during
orbit trim maneuvers. The gaps on day 071 02:00:00 to
077 03:15:00 were the result of placing the instrument in sleep mode
during a thruster swap. The remaining gaps were due to telemetry gaps.
During S48 (from 2009-091), S49, S50, S51 (to 2009-181) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 098, 102, 108, 118, 123, 124, 125, 134, 150, 161, 165, 169, 170,
and 177 resulting in one or more L1A files being absent
from the data for those days. The gaps on days 102, 118, 123, 134, 150,
161, and 177 06:25:04 to 177 09:09:19 were the result of placing the
instrument in sleep mode during orbit trim maneuvers.
The remaining gaps were due to telemetry gaps.
During S51 (from 2009-182), S52, S53 (to 2009-273) there were no
unexpected processor resets. Data gaps of more than one hour
occurred on days 193, 209, 221, 222, 228, 234, 241, 248, 258, and 259
resulting in one or more L1A files being absent
from the data for those days. The gaps on days 193, 209, 228, 241,
and 248 were the result of placing the instrument in sleep mode
during orbit trim maneuvers.
The remaining gaps were due to telemetry gaps.
During S53 (from 2009-274), S54, S55, S56 (to 2009-365) there were no
unexpected processor resets. Data gaps of more than one hour
occurred on days 289, 294, 309, 326, 349, 354, and 355,
resulting in one or more L1A files being absent
from the data for those days. The gaps on days 289, 294, 309, 326, 349,
and 354 (05:59:48-08:41:54) were the result of placing the instrument
in sleep mode during orbit trim maneuvers.
The remaining gaps were due to telemetry gaps.
During S56 (from 2010-001), S57, S58 (to 2010-090) there were no
unexpected processor resets. Data gaps of more than one hour
occurred on days 002, 003, 004, 005, 006, 007, 008, 016, 021, 032,
046, 065, and 085 resulting in one or more L1A files being absent
from the data for those days. The gaps on days 016, 021, 032, and 085
were the result of placing the instrument in sleep mode during
orbit trim maneuvers. The gaps on days 002 10:12:05 to 006 02:43:36
were the result of the instrument being turned Off because of an SSPS
Trip on the spacecraft. The gaps on days 006 02:43:36 to 007 15:24:57
were the result of the instrument being in sleep mode to run
diagnostics on the instrument.
The remaining gaps were due to telemetry gaps.
During S58 (from 2010-091), S59, S60, S61 (to 2010-181) there were no
unexpected processor resets. Data gaps of more than one hour
occurred on days 100, 101, 107, 108, 109, 119, 131, 141, 142, 143,
148, 164, 175, and 181 resulting in one or more L1A files being absent
from the data for those days. The gaps on days 100, 101, 119, 131,
143, 148, 164, 175, and 181 were the result of placing the instrument
in sleep mode during orbit trim maneuvers.
The remaining gaps were due to telemetry gaps.
During S61 (from 2010-182), S62, S63 (to 2010-273) there were no
unexpected processor resets. Data gaps of more than one hour
occurred on days 188, 189, 191, 199, 230, 231, 232, 233, 246, and 256.
resulting in one or more L1A files being absent
from the data for those days. The gaps on days 191, 199, and 246
were the result of placing the instrument
in sleep mode during orbit trim maneuvers.
The remaining gaps were due to telemetry gaps.
During S63 (from 2010-274), S64, S65 (to 2010-365) there were no
unexpected processor resets. Data gaps of more than one hour
occurred on days 274, 275, 276, 285, 299, 306-328, 337, 338, and 339
resulting in one or more L1A files being absent
from the data for those days. The gaps on days 306 21:29:41 to
319 20:00:10 were the result of the instrument being turned Off because
of a spacecraft safing event. The gaps on days 319 20:00:10
to 328 19:35:00 were the result of the instrument being in sleep mode
to run diagnostics on the instrument.
The remaining gaps were due to telemetry gaps.
During S65 (from 2011-001), S66, S67 (to 2011-090) there were no
unexpected processor resets. Data gaps of more than one hour
occurred on days 010, 014, 024, 025, 059, 060, and 072
resulting in one or more L1A files being absent
from the data for those days. The gap on day 014 was the result of
placing the instrument in sleep mode during an orbit trim maneuver.
The remaining gaps were due to telemetry gaps.
During S67 (from 2011-091) and S68 (to 2011-181) there were no
unexpected processor resets. Data gaps of more than one hour occurred
on day 131 resulting in one or more L1A files being absent fron the data
for that day. The gap on day 131 was due to telemetry gaps.
During S68 (from 2011-182), S69, and S70 (to 2011-273) there were no
unexpected processor resets. Data gaps of more than one hour
occurred on days 220, 222-226, 228, 232, 235, 236, 250, 263, and 268
resulting in one or more L1A files being absent from the data for those
days. The gap on day 263 was the result of placing the instrument in
sleep mode during an orbit trim maneuver. The remaining gaps were due
to telemetry gaps.
During S70 (from 2011-274) and S71 (to 2011-365) there were no
unexpected processor resets. Data gaps of more than one hour
occurred on days 279, 313, 320, 328, 351, 357, 358, and 359
resulting in one or more L1A files being absent from the data for those
days. The gaps on days 328 and 351 were the result of placing the
instrument in sleep mode during an orbit trim maneuver. The remaining
gaps were due to telemetry gaps.
During S71 (from 2012-001) and S72 (to 2012-091) there were no
unexpected processor resets. Data gaps of more than one hour
occurred on days 006, 024, 027, 028, 029, 070, and 077
resulting in one or more L1A files being absent from the data for those
days. The gap on day 070 was the result of placing the
instrument in sleep mode during an orbit trim maneuver. The remaining
gaps were due to telemetry gaps.
During S72 (from 2012-092) , S73, and S74 (to 2012-182) there were no
unexpected processor resets. Data gaps of more than one hour
occurred on days 110, 111, 115, 135, 151, 152, 162, 167, 170,
and 173-177 resulting in one or more L1A files being absent from the
data for those days. The gaps on days 115, 135, 151, 162, and 173 were
the result of placing the instrument in sleep mode during an orbit trim
maneuver. The remaining gaps were due to telemetry gaps.
During S74 (from 2012-183) and S75 (to 2012-274) there were no
unexpected processor resets. Data gaps of more than one hour
occurred on days 185, 190-192, 196, 220, 230, 233, 234, and 270
resulting in one or more L1A files being absent from the data for those
days. The gap on day 220 were the result of placing the instrument in
sleep mode during an orbit trim maneuver. The remaining gaps were due
to telemetry gaps.
During S75 (from 2012-275) and S76 (to 2012-366) there were no
unexpected processor resets. Data gaps of more than one hour
occurred on days 283, 293-303, 304, 318, 319, 322, 327, and 335
resulting in one or more L1A files being absent from the data for those
days. The gaps on days 283, 322, and 327 were the result of placing
the instrument in sleep mode during an orbit trim maneuver. The gaps
on days 293-303 were the result of the instrument being turned off
during the Cassini Propellant Guage Test. The remaining gaps were due
to telemetry gaps.
During S76 (from 2013-001), S77, and S78 (to 2013-090) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 011, 030, 055, and 061 resulting in one or more L1A files being
absent for those days. The gaps on days 030, 055, and 061 were the
result of placing the instrument in sleep mode during an orbit trim
maneuver. The remaining gaps were due to telemetry gaps.
During S78 (from 2013-091) and S79 (to 2013-181) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 120, 134, 158, 162, 169, and 174 resulting in one or more L1A files
being absent for those days. The gaps on days 120 and 162 were the
result of placing the instrument in sleep mode during an orbit trim
maneuver. The remaining gaps were due to telemetry gaps.
During S79 (from 2013-182) and S80 (to 2013-273) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 196, 200, 219, and 258 resulting in one or more L1A files
being absent for those days. The gaps on days 196, 200, and 219 were
the result of placing the instrument in sleep mode during an orbit trim
maneuver. The remaining gaps were due to telemetry gaps.
During S80 (from 2013-274), S81, and S82 (to 2013-365) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 306, 309-310, 312-315, and 351-352 resulting in one or more L1A
files being absent for those days. The gaps on days 306, 351, and 352
were the result of placing the instrument in sleep mode during an orbit
trim maneuver. The remaining gaps were due to telemetry gaps.
During S82 (from 2014-001), and S83 (to 2014-090) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 010-011, 048, 079, and 082 resulting in one or more L1A files being
absent for those days. The gaps on days 048 and 079 were the result of
placing the instrument in sleep mode during an orbit trim maneuver. The
remaining gaps were due to telemetry gaps.
During S83 (from 2014-091) and S84 (to 2014-181) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 108, 109, and 127-129 resulting in one or more L1A files being
absent for those days. All of the gaps were due to telemetry gaps.
During S84 (from 2014-182) and S85 (to 2014-273) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 221, 236, 250, 254, and 255 resulting in one or more L1A files
being absent for those days. The gaps on days 221 and 250 were the
result of placing the instrument in sleep mode during an orbit trim
maneuver. The remaining gaps were due to telemetry gaps.
During S85 (from 2014-274) and S86 (to 2014-365) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 282, 284, 287-288, 295-296, 302-303, 306-307, 342, and 364
resulting in one or more L1A files being absent for those days. The gaps
on days 282 and 364 were a result of placing the instrument in sleep
mode during an orbit trim maneuver. The larger quantity of gaps were
associated with the STEREO-B spacecraft emergency. The remaining gaps
due to telemetry gaps.
During S87 (from 2015-001) and S88 (to 2015-090) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 031, and 046 resulting in one or more L1A files being absent for
those days. All of the gaps were due to OTM step down and recovery.
During S88 (from 2015-091) and S89 (to 2015-181) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 096, 121, 151, and 152 resulting in one or more L1A files being
absent for those days. One gap was due to either OTM step down or start
of sequence reboot. The others were due to DSN issues.
During S89 (from 2015-182), S90, and S91 (to 2015-273) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 187, 192, 224, 234, 235, and 273 resulting in one or more L1A files
being absent for those days. The gap on day 273 was due to data
policing after an Ops Table Load. All other gaps were due to DSN
issues.
During S91 (from 2015-274), and S92 (through 2015-365) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 275, 279, 292, 311-312, 328-329, and 364 resulting in one or more
L1A files being absent for those days. The gaps on days 275, 279, and
were due to OTMs. All other gaps were due to DSN issues.
During S92 (from 2016-001), and S93 (through 2016-091) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 021, 022, 023, 025, 026, 034, 035, 039, 061, 065, 066, 067, 068,
069, and 085 resulting in one or more L1A files being absent for those
days. The gaps on days 023, 034, 039, and 085 were due to OTMs. All
the other gaps were due to DSN issues.
During S93 (from 2016-092), S94, and S95 (through 2016-183) there were
no unexpected processor resets. Data gaps of more than one hour occurred
on days 113, 130, 146, and 163 resulting in one or more L1A file being
absent for those days. The gaps on days 113, 130, and 163 were due to
OTMs. The other gap was due to DSN issues.
During S95 (from 2016-184), S96 (through 2016-274) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 199, 202, 215, 238, 249 and 250 resulting in one or more L1A files
being absent for those days. The gaps on days 199 and 215 were due to
OTMs. Data loss on 238 was due to a direct to instrument IEB load.
The other gap was due to DSN issues.
During S96 (from 2016-275) and S97 (through 2016-366) there were
no unexpected processor resets. Data gaps of more than one hour occurred
on days 339, 347, and 351 resulting in one or more L1A file being
absent for those days. The gap on day 339 was due to an OTM. The
gaps were due to DSN issues.
During S97 (from 2017-001) and S98 (through 2017-090) there were no
unexpected processor resets. Data gaps of more than one hour occurred on
days 040, 041, 044, and 071, resulting in one or more L1A files being
being absent for those days. Data loss on 044 was due to a direct to the
instrument IEB load. The other gaps were due to DSN issues.
During S98 (from 2017-091) and S99 and S100 (through 2017-181) there
were no unexpected processor resets. Data gaps of more than one hour
occurred on days 154, and 155, resulting in one or more L1A files being
being absent for those days. Data loss due to DSN issues.
During S100 (from 2017-182) and S101 (through end of mission on
2017-258) there were no unexpected processor resets. Science data gaps
of more than 1 hour occurred on days 207-210, 213-215, 234-236, and 258,
resulting in one or more L1A files being absent for those days. Data
loss on 213-215 was due to DSN issues. Data loss on 258, was due to
end of mission. Data losses on 207-210 and 234-236 were due to putting
the instrument in sleep so that new tables could be loaded to the
instrument over several DSN passes.
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.
Data collected at low altitudes at Titan must be used with
caution. There appears to be significant contamination due to
thruster exhaust scattering into the instrument.
Velocity compensation was incorrectly configured and the data labeled
OSNT is invalid for time periods 2008-004T03:15:00 to 2008-004T04:45:00,
2008-015T14:30:00 to 2008-015T16:00:00, and 2008-039T20:15:00 to
2008-039T21:45:00.
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