DATA SET OVERVIEW : The Cassini Ion and Neutral Mass Spectrometer (INMS) level 1A data set includes all mass samples for the entire Cassini mission. The data set includes mass spectra data from the instrument checkout periods, SOI and the entire Saturn tour. The data is organized as a spread sheet with one row for each sample period. Each column in the spread sheet contains the ancillary data and the output of the counters. PARAMETERS : The data set includes both high sensitivity (C1) and low sensitivity (C2) count rates collected during the tour. The count rates are reported as total counts per 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. PROCESSING : The data in this data set is minimally processed. The counter sums are extracted from the instrument telemetry and the values of the included ancillary data are computed. The ancillary data comes from a number of sources including instrument science telemetry, instrument housekeeping telemetry, instrument command tables, spacecraft attitude and ephemerides of the spacecraft and planetary body and moons. COORDINATE SYSTEM : Position, velocity and orientation information contained in this data set is provided with respect to a number of coordinate systems. Saturn relative information expressed in the IAU Saturn frame is always included. When the spacecraft is within one hour of a targeted flyby, target relative position, velocity and orientation information is provided expressed in the target's IAU frame. The spacecraft velocity with respect to a target body, expressed in the spacecraft body frame is also included within one hour of a targeted flyby. The IAU frames are centered at the center of the reference body, Saturn, Titan, or another object of interest. They are rotating coordinate frames which, in the case of Saturn, rotates with the magnetic field. For other bodies, the frame rotates with the surface. Definitions of the coordinate frames may be found in 'The Explanatory Supplement to the Astronomical Almanac' [SEIDELMANN1992] Longitudes are positive westward. 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.

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.