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 ---------------------------------------------------------------------------- ORB1801 155 118 953 1983-11-11T00:36:08.229Z 1983-11-11T01:00:23.966Z ORB1806 157 118 953 1983-11-16T00:26:19.896Z 1983-11-16T00:50:54.360Z ORB1813 156 118 953 1983-11-23T00:24:15.517Z 1983-11-23T00:48:40.309Z ORB1820 154 118 953 1983-11-30T00:22:17.711Z 1983-11-30T00:46:24.175Z ORB1828 151 118 953 1983-12-08T00:19:27.981Z 1983-12-08T00:43:05.521Z ORB1836 155 118 953 1983-12-16T00:22:38.265Z 1983-12-16T00:46:53.542Z ORB1844 157 118 953 1983-12-24T00:20:36.377Z 1983-12-24T00:45:10.841Z ORB1847 152 118 953 1983-12-27T00:16:40.337Z 1983-12-27T00:40:27.152Z ORB1853 315 118 953 1984-01-02T00:01:18.627Z 1984-01-02T01:01:05.652Z ORB1858 418 118 953 1984-01-07T00:09:04.297Z 1984-01-07T01:01:03.019Z ORB1864 289 118 953 1984-01-13T00:15:42.562Z 1984-01-13T01:01:04.331Z ORB1866 155 118 953 1984-01-15T00:16:19.831Z 1984-01-15T00:40:35.109Z ORB1869 155 118 953 1984-01-18T00:16:30.121Z 1984-01-18T00:40:45.111Z ORB1895 152 118 953 1984-02-13T00:15:49.795Z 1984-02-13T00:40:33.135Z 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.