PVO Ion Mass Spectrometer high-resolution data are stored in single-orbit ASCII files. All of the data files have the same internal structure, which is described by the single format file OIMSDATA.FMT. File structure characteristics which may vary from file to file (# of records, start/stop time, etc.) are described in the individual PDS label files (*.LBL). Columns in all data files: ======================================================= name type description ------------------------------------------------------- PVO TIME char Date and time in format YYDOY FSEC, where YY is the year, DOY is the day-of-year & FSEC is the decimal second-of-day DWELL int Dwell time (time interval between samples, msec) DWELL = (TIME - UT)*1000/(n-1) BITS int Telemetry bit rate LAT float Venusian Latitude LON float Venusian Longitude ALT float Altitude SZA float Solar Zenith Angle SHA float Solar Hour Angle
MASS1 int Mass of Sample 1 DEN1 float Number density of Sample 1 MASS2 int Mass of Sample 2 DEN2 float Number density of Sample 2 . . . . . . . . . MASS55 int Mass of Sample 55 DEN55 float Number density of Sample 55 The values 999 and 9.9999e+04 are the missing data values for mass and density respectively. The value 99999.999 is the missing data value for the second-of-day part of the time column. Negative values in a density column indicate flagged (unreliable) data values. Data Files (.TAB extension) The high-resolution data files on this disk are ASCII table files, each having 118 columns and record length 953 bytes. Information about the individual files (number of records, start and stop times, etc.) can be obtained from the PDS label file accompanying each *.TAB file. This label file has the same filename as the data file but with .TAB replaced by .LBL. List of data files: ============================================================================ Name Records Cols Len Start Stop ---------------------------------------------------------------------------- ORB3304 270 118 953 1987-12-23T01:18:37.823Z 1987-12-23T02:03:59.625Z ORB3321 270 118 953 1988-01-09T01:25:34.612Z 1988-01-09T02:10:56.412Z ORB3322 270 118 953 1988-01-10T01:26:04.370Z 1988-01-10T02:11:16.426Z ORB3323 275 118 953 1988-01-11T01:26:32.907Z 1988-01-11T02:11:45.649Z ORB3324 271 118 953 1988-01-12T01:26:52.656Z 1988-01-12T01:54:54.922Z ORB3326 122 118 953 1988-01-14T01:27:52.137Z 1988-01-14T01:47:23.660Z ORB3327 233 118 953 1988-01-15T01:28:21.941Z 1988-01-15T02:07:06.932Z ORB3328 260 118 953 1988-01-16T01:28:53.931Z 1988-01-16T02:11:34.438Z ORB3329 262 118 953 1988-01-17T01:29:23.139Z 1988-01-17T02:11:45.579Z ORB3357 369 118 953 1988-02-14T01:40:50.526Z 1988-02-14T02:26:31.792Z ORB3358 374 118 953 1988-02-15T01:41:08.292Z 1988-02-15T02:26:47.308Z ORB3386 291 118 953 1988-03-14T01:45:53.316Z 1988-03-14T02:31:33.833Z ORB3387 425 118 953 1988-03-15T01:45:50.822Z 1988-03-15T02:31:37.838Z ORB3388 438 118 953 1988-03-16T01:45:55.325Z 1988-03-16T02:31:48.843Z ORB3389 438 118 953 1988-03-17T01:46:01.345Z 1988-03-17T02:31:54.863Z ORB3390 437 118 953 1988-03-18T01:46:07.366Z 1988-03-18T02:32:00.383Z ORB3391 438 118 953 1988-03-19T01:46:13.383Z 1988-03-19T02:32:06.399Z ORB3392 438 118 953 1988-03-20T01:46:20.402Z 1988-03-20T02:32:13.420Z ORB3393 438 118 953 1988-03-21T01:46:26.922Z 1988-03-21T02:32:19.940Z ORB3394 188 118 953 1988-03-22T01:46:27.443Z 1988-03-22T02:05:14.951Z ORB3395 437 118 953 1988-03-23T01:46:34.464Z 1988-03-23T02:32:21.480Z ORB3396 437 118 953 1988-03-24T01:46:41.985Z 1988-03-24T02:32:29.003Z ORB3397 437 118 953 1988-03-25T01:46:43.504Z 1988-03-25T02:32:37.021Z ORB3398 11 118 953 1988-03-26T02:13:00.501Z 1988-03-26T02:14:03.502Z ORB3399 437 118 953 1988-03-27T01:47:00.008Z 1988-03-27T02:32:53.024Z Catalog Files (.CAT extension) Catalog data, which includes instrument, dataset, mission and spacecraft descriptions, can be found in the *.CAT files in the CATALOG directory on this disk.