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 ---------------------------------------------------------------------------- ORB3030 370 118 953 1987-03-23T23:49:51.133Z 1987-03-24T00:35:08.147Z ORB3031 76 118 953 1987-03-25T00:05:29.829Z 1987-03-25T00:17:18.598Z ORB3032 369 118 953 1987-03-25T23:50:07.359Z 1987-03-26T00:35:17.378Z ORB3033 224 118 953 1987-03-26T23:50:14.852Z 1987-03-27T00:35:25.120Z ORB3034 223 118 953 1987-03-27T23:50:17.609Z 1987-03-28T00:35:22.626Z ORB3035 372 118 953 1987-03-28T23:50:18.094Z 1987-03-29T00:35:34.112Z ORB3036 230 118 953 1987-03-29T23:50:23.570Z 1987-03-30T00:35:29.586Z ORB3037 370 118 953 1987-03-30T23:50:22.062Z 1987-03-31T00:35:35.076Z ORB3038 39 118 953 1987-04-01T00:06:39.559Z 1987-04-01T00:17:59.802Z ORB3039 332 118 953 1987-04-01T23:50:36.281Z 1987-04-02T00:35:53.280Z ORB3040 216 118 953 1987-04-02T23:50:49.828Z 1987-04-03T00:36:00.846Z ORB3041 218 118 953 1987-04-03T23:50:52.336Z 1987-04-04T00:36:03.605Z ORB3042 360 118 953 1987-04-04T23:50:47.102Z 1987-04-05T00:36:10.114Z ORB3043 216 118 953 1987-04-05T23:50:54.609Z 1987-04-06T00:36:05.630Z ORB3044 262 118 953 1987-04-06T23:51:01.633Z 1987-04-07T00:36:12.898Z ORB3045 72 118 953 1987-04-08T00:08:20.894Z 1987-04-08T00:19:32.149Z ORB3046 264 118 953 1987-04-08T23:51:02.711Z 1987-04-09T00:36:15.477Z ORB3083 168 118 953 1987-05-16T00:03:18.712Z 1987-05-16T00:48:02.994Z ORB3084 267 118 953 1987-05-17T00:03:30.488Z 1987-05-17T00:48:24.513Z ORB3086 171 118 953 1987-05-19T00:04:21.063Z 1987-05-19T00:49:24.082Z ORB3087 72 118 953 1987-05-20T00:20:59.096Z 1987-05-20T00:32:10.351Z ORB3088 81 118 953 1987-05-21T00:05:19.821Z 1987-05-21T00:18:04.828Z ORB3089 173 118 953 1987-05-22T00:06:12.375Z 1987-05-22T00:50:34.107Z ORB3090 173 118 953 1987-05-23T00:06:41.623Z 1987-05-23T00:51:04.104Z ORB3091 95 118 953 1987-05-24T00:23:11.651Z 1987-05-24T00:51:41.660Z ORB3092 170 118 953 1987-05-25T00:07:43.627Z 1987-05-25T00:52:04.673Z ORB3093 272 118 953 1987-05-26T00:07:51.142Z 1987-05-26T00:52:44.417Z ORB3094 72 118 953 1987-05-27T00:24:49.694Z 1987-05-27T00:36:00.949Z ORB3095 226 118 953 1987-05-28T00:08:29.969Z 1987-05-28T00:53:17.233Z ORB3096 218 118 953 1987-05-29T00:09:25.726Z 1987-05-29T00:54:17.740Z ORB3097 201 118 953 1987-05-30T00:09:58.230Z 1987-05-30T00:54:50.243Z ORB3098 92 118 953 1987-05-31T00:26:58.231Z 1987-05-31T00:55:22.762Z ORB3099 212 118 953 1987-06-01T00:11:03.269Z 1987-06-01T00:55:49.783Z 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.