Data Set Information
DATA_SET_NAME ICE MAGNETOMETER DATA V1.0
DATA_SET_ID ICE-C-MAG-3-RDR-GIACOBIN-ZIN-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview: These data were obtained from the JPL magnetometer experiment on ICE (Principal Investigator: E.J. Smith; data provided by J. Wolf). The instrument produces three, high-accuracy, triaxial measurements per second of the magnetic field strength in 8 ranges, i.e., +/-4 nT (lowest full range), 14, 42, 144, 640, 4000, 22000, and 140000 nT (highest full range) and a sensitivity of 1/256 of each full range, in a 0-3 Hz pass band. During the G-Z encounter the instrument range was switched automatically between the 4 lowest ranges depending on the field intensity, giving sensitivities of 0.015, 0.051, 0.17 and 0.57 nT respectively. The time resolution is 1/3 sec from the start of Day 253 (September 10, 1985) until Day 255 (September 12, 1985), 18:38. At that time the bit rate dropped from 1024 to 512 bps, and the time resolution decreased to 2/3 sec. The coordinate system for the magnetic field components is the I,S coordinate system, defined by the JPL group before launch. I is the unit vector in the direction of the ICE spin axis (positive in the northward direction), and S is the unit vector from the spacecraft to the Sun. The z-axis is equal to I, the y-axis to the normalized cross-product I x S, and the x-axis to Y x Z. The I,S coordinate system is approximately the same as the Solar Ecliptic (SE) system since the spacecraft z-axis is maintained within half a degree of perpendicular to the Ecliptic plane. (SE is defined the same way as GSE, but with the spacecraft [point of observation] substituted for Earth). While the JPL reduction program eliminates most noise spikes, there is a small number that do appear in these data. JPL does not hand-edit the high resolution data, since there is such a volume of it. Users should check for noise spikes when doing averaging or other analyses. There is no special flag for 'bad' or missing data. A scan of the 5 days of high resolution data at JPL revealed the following noise spikes: Time Field magnitude ---- --------------- Day 253, 10:11:59.84 47.25 Day 254, 03:51:28.21 59.17 04:05:17.84 56.19 10:10:55.31 59.68 11:06:13.15 128.07 12:04:23.92 62.73 Day 255, 09:07:17.48 57.75 09:07:17.82 185.49 Day 256, 07:35:54.94 57.58 21:08:09.00 23.83 23:01:15.94 35.20 Day 257, 10:08:07.77 46.06 20:03:15.75 51.07 The following information (and the table of noise spikes given above) has been provided by J. Wolf (JPL), after examining plots of the magnetic field data during the comet encounter: The highest legitimate value of Bmagnitude is 59.21 at 11:01:01.29 on Day 254, at the time of closest approach to the comet. On Day 254, one should eliminate points with Bmagnitude greater than 40 from 09:00 to 11:00 and from 11:10 to 13:00. During the interval 11:00 to 11:10, points with Bmagnitude greater than 60 should be eliminated. For the rest of this 5 day interval, one should eliminate points with Bmagnitude greater than 20 nT.
DATA_SET_RELEASE_DATE 3000-01-01T00:00:00.000Z
START_TIME 1985-09-10T10:00:00.040Z
STOP_TIME 1985-09-14T08:51:14.500Z
MISSION_NAME INTERNATIONAL COMETARY EXPLORER
MISSION_START_DATE 1983-12-22T12:00:00.000Z
MISSION_STOP_DATE N/A (ongoing)
TARGET_NAME GIACOBINI-ZINNER
TARGET_TYPE COMET
INSTRUMENT_HOST_ID ICE
INSTRUMENT_NAME MAGNETOMETER
INSTRUMENT_ID MAG
INSTRUMENT_TYPE MAGNETOMETER
NODE_NAME Small Bodies
ARCHIVE_STATUS ARCHIVED
CONFIDENCE_LEVEL_NOTE Confidence Level Overview : N/A
CITATION_DESCRIPTION Smith, E.J., and J. Wolf, ICE MAGNETOMETER DATA V1.0, ICE-C-MAG-3-RDR-GIACOBIN-ZIN-V1.0, NASA Planetary Data System, 1995.
ABSTRACT_TEXT These data were obtained from the JPL magnetometer experiment on ICE (Principal Investigator: E.J. Smith produces three, high-accuracy, triaxial measurements per second of the magnetic field strength in 8 ranges, i.e., +/-4 nT (lowest full range), 14, 42, 144, 640, 4000, 22000, and 140000 nT (highest full range) and a sensitivity of 1/256 of each full range, in a 0-3 Hz pass band. During the G-Z encounter the instrument range was switched automatically between the 4 lowest ranges depending on the field intensity, giving sensitivities of 0.015, 0.051, 0.17 and 0.57 nT respectively. The time resolution is 1/3 sec from the start of Day 253 (September 10, 1985) until Day 255 (September 12, 1985), 18:38. At that time the bit rate dropped from 1024 to 512 bps, and the time resolution decreased to 2/3 sec.
PRODUCER_FULL_NAME INTERNATIONAL HALLEY WATCH
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