Data Set Information
|
| DATA_SET_NAME |
ROSETTA-ORBITER 67P ROSINA 2 EXT3 V2.0
|
| DATA_SET_ID |
RO-C-ROSINA-2-EXT3-V2.0
|
| NSSDC_DATA_SET_ID |
|
| DATA_SET_TERSE_DESCRIPTION |
|
| DATA_SET_DESCRIPTION |
Data set Version 2.0 : The Science RIDs from the October 2018 review have been applied to this ROSINA dataset. The ROSINA team also found corrupted files in the RTOF, DFMS, and COPS science data V1.0 of this dataset, these corrupted files have been removed in the V2.0. The list of these removed files can be found in the REMOVED_L2_V1_TO_V2.ASC file. Some of the DFMS PDS files were missing in the L2 V1.0 and were added them into the V2.0. The COPS science HK order also changed without modifying the structure: the COPS HK table composed by the 5 last standard COPS HK blocks are now in time order, this change is reflected in the latest version of the ROSINA EAICD document. As a result, V2.0 of this CODMAC L2 dataset has been created. 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 analysing 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. Explanations 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 : COPS data are calibrated. However, the calibration factor has been determined for Nitrogen gas, and may not be appropriate for the the coma composition. For this the data from RTOF or DFMS have to be taken into account. Note on the DFMS and RTOF data: The user of our level 2 data has to make the conversion from pixel to mass and from ADC counts to ion current himself. In this way he will be aware that the precision is limited and depends on many parameters and he will use the data accordingly. The procedure required to calibrate the DFMS is described in our User manual, Annex D1 (DOCUMENT directory). ROSINA team are developed the necessary algorithms, putting emphasis on the quality control for the algorithm. They are defining quality flags for the data which will then tell the user how well the mass scale and the intensity scale have been defined. For calibrated level 3 data with calibrated mass scale and intensity we refer the user to the level 3 data. Processing : The DPU measures the ion current. To calculate the pressure, the DPU use the following formula: For the nude gauge: p(mbar)NG : (Ion_current_fil(A) - Ion_offset_fil(A)) / (Immission_current_fil(A) - Immission_offset_fil(a)) * S For the ram gauge: p(mbar)RG : (Ion_current_mic(A) - Ion_offset_mic(A)) / (Immission_current_mic(A) - Immission_offset_mic(a)) * S The Ion offset value is measured in background mode, that is after switching on and then every 24h with the filament and the microtips, respectively off. S is the calibration factor, it is about 30 for the nude gauge and 5 for the ram gauge. This factor depends of the temperature and the ambient gas. Flux formula for the Ram gauge: phi_out : 0.25 * SQRT((8*kB+T_RG) / (pi * mass)) * (p_RG / (T_RG*kB)) phi_out : gas flux [1/m2*s] kB : Boltzmann-constant : 1.38e-23 [J/K] T_RG : ram gauge temp. [K] mass : 18 amu : 2.9889e-26 [ Kg] (H2o is the default mass) p_RG : ram pressure [Pa] : 100*[p(mbar)RG] The pressure values given directly in the COPS housekeeping are pressures for N2 at 20DegC. In order to derive the density this pressure value has therefore to be converted to density as follows: n (m-3) : p /(kT) with p in Pa; T:293K, k:1.380*10e-23 J/K e.g. if p:1*10e-10 mbar n:2.4*10e12 m-3 : 2.4*10e6 cm3 In order to get the real density, the relative contribution of the different species in the coma has to be known, as ionization cross sections are different for each gas. For more details see the ROSINA user manual. Software : No software is provided. 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.
|
| DATA_SET_RELEASE_DATE |
2019-01-30T00:00:00.000Z
|
| START_TIME |
2016-06-28T11:23:28.332Z
|
| STOP_TIME |
2016-09-30T10:39:26.282Z
|
| MISSION_NAME |
INTERNATIONAL ROSETTA MISSION
|
| MISSION_START_DATE |
1995-03-01T12:00:00.000Z
|
| MISSION_STOP_DATE |
N/A (ongoing)
|
| TARGET_NAME |
67P/CHURYUMOV-GERASIMENKO 1 (1969 R1)
|
| TARGET_TYPE |
COMET
|
| INSTRUMENT_HOST_ID |
RO
|
| INSTRUMENT_NAME |
ROSETTA ORBITER SPECTROMETER FOR ION AND NEUTRAL ANALYSIS
|
| INSTRUMENT_ID |
ROSINA
|
| INSTRUMENT_TYPE |
MASS SPECTROMETER
|
| NODE_NAME |
Small Bodies
|
| ARCHIVE_STATUS |
LOCALLY ARCHIVED
|
| CONFIDENCE_LEVEL_NOTE |
Confidence Level Overview : All data have been validated by the ROSINA team and found as expected. Any exceptions are noted by the DATA_QUALITY field in the label files.
|
| CITATION_DESCRIPTION |
Altwegg, K., ROSETTA-ORBITER 67P ROSINA 2 EXT3 V2.0, RO-C-ROSINA-2-EXT3-V2.0, ESA Planetary Science Archive, NASA Planetary Data System, 2019
|
| ABSTRACT_TEXT |
This data set contains CODMAC level 2 science data acquired by the COPS, DFMS and RTOF ROSINA sensors between 2016-06-28 and 2016-06-30 during the Extension phase 3 of the Rosetta mission at the comet 67P/CG. V2.0 : Some missing DFMS PDS files were added and corrupted files have been removed.
|
| PRODUCER_FULL_NAME |
KATHRIN ALTWEGG
|
| SEARCH/ACCESS DATA |
SBN Comet Website
|
|
.png)
.png)
