DATA_SET_DESCRIPTION |
Data set Overview : Rosetta was at distances between 26.89 and 0 km from the comet during this time. The COPS HK packet was generated every 4s during the last hour of the mission. ROSINA was permanently analyzing the coma of the comet with all three sensors, except during wheel offloadings when the mass spectrometers DFMS and RTOF were in standby and during orbit control manoeuvers, when all sensors were off. Explanation on the data generation of the ROSINA sensors can be found in the OPERATION_LOGBOOK.ASC Parameters : DFMS and RTOF data contain neutral gas data as well as ion data. The data are raw, uncalibrated data. COPS data contains nude gauge pressure values of the combined spacecraft and cometary signal. Calibration : The level 3 data products are calibrated with mass scale and intensity. The procedure required to calibrate the RTOF and DFMS data is described in our User manual, Annex D1 (DOCUMENT directory). The ROSINA Team defined quality flags for the data which will then tell the user how well the mass scale and the intensity scale have been defined. Processing : Processing the RTOF and DFMS CODMAC L2 PDS to L3 PDS calibrated data is detailed in the SOFT_RTOF_L2_TO_L3.PDF and SOFT_DFMS_L2_TO_L3.PDF documents. These documents also contain use and installation instructions of the software. Software : Software to convert L2 to L3 data is provided. It produces the calibrated data from the L2 data. Another software is also provided to enhance the mass scale of the DFMS CODMAC L3 products. Media/Format : The standard distribution format for the data is an electronic volume. Coordinate System : The geometry items SC_SUN_POSITION_VECTOR, SC_TARGET_POSITION_VECTOR and SC_TARGET_VELOCITY_VECTOR provided in the label of the data product are relative to the Earth Mean Equator and Equinox reference frame of J2000. SUB_SPACECRAFT_LATITUDE, SUB_SPACECRAFT_LONGITUDE are given in the Cheops reference frame. The SPACECRAFT_ALTITUDE gives the distance to the spacecraft from the target center of mass. These parameters are computed at time t:START_TIME. Distances are given in km, angles in degrees. Cheops Reference Frame : Scholten, F., Preusker, F., Jorda, L, and Hviid, S., Reference Frames and Mapping Schemes of Comet 67P/C-G, RO-C-MULTI-5-67P-SHAPE-V1.0:CHEOPS_REF_FRAME_V1, NASA Planetary Data System and ESA Planetary Science Archive, 2015.
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