ROSETTA Measured CK file by ESA SPICE Service =========================================================================== This file contains the S/C attitude quaternions extracted from the corresponding telemetry housekeeping quaternions data. It has been created with the utility MSOPCK by the ESA SPICE Service on September 7, 2017. Objects ------------------------------------------------------------------------ This file contains orientation and angular velocity data for the ROSETTA spacecraft frame, 'ROS_SPACECRAFT', relative to the Earth Mean Equator and Equinox of J2000, 'J2000'. The NAIF ID code for ROS_SPACECRAFT is -226000 Approximate Time Coverage ------------------------------------------------------------------------ See "MSOPCK Setup Parameters and Run-Time Traceback" section below. Status ------------------------------------------------------------------------ This kernel is an operational product of the ROSETTA Science Operations Team. It is intended to be used by ROSETTA Instrument Teams and scientists for data analysis. Pedigree ------------------------------------------------------------------------ ESOC/FD is responsible for Housekeeping data delivering. This file has been created using MSOPCK using as input a quaternions from the telemetry file processed by the ROSETTA Science Operations Team. Usage ------------------------------------------------------------------------ This file should be used together with the kernel set described below: NAIF0011.TLS is a Leapseconds Kernel file used in conversions between ephemeris time and UTC (coordinated universal time). ROS_160929_STEP.TSC is the official Spacecraft Clock Kernel file used in conversions between the ROS time and ephemeris time. ROS_V27.TF is a Frames Kernel file required to establish relationships between frames used in geometry computations. The usage of this CK with other versions of these files shall be analysed and handled with care. Accuracy ------------------------------------------------------------------------ In some occasions the measured quaternions may be of reduced quality. For example if the number of stars tracked by the star tracker is not sufficient and the attitude is controlled only based on gyro-information for a period of time, the on-board estimated quaternions can drift. In such cases the available information would have to be analysed specifically. An attitude profile resulting from such an analysis (based on different input sources) is called "reconstructed" in the current terminology. The CK file is divided in interpolation segments. The segments are defined by the MAXIMUM_VALID_INTERVAL of the configuration file (available below). The time set by that parameter determines the maximum time allowed in between two quaternions; if the time in between quaternions exceeds that value a new interpolation segment is defined and no interpolation is performed in between those segments and therefore this CK does not provide information for that period. If the MAXIMUM_VALID_INTERVAL is not set interpolation is performed for the whole CK coverage. References ------------------------------------------------------------------------ [1] CK Required Reading [2] SCLK Required Reading [3] TIME Required Reading [4] MSOPCK User Guide Contact Information ------------------------------------------------------------------------ If you have any questions regarding this file contact SPICE support at ESAC: Marc Costa Sitja (+34) 91-8131-457 mcosta@sciops.esa.int, esa_spice@sciops.esa.int or NAIF at JPL: Boris Semenov (818) 354-8136 Boris.Semenov@jpl.nasa.gov MSOPCK Setup Parameters and Run-Time Traceback ------------------------------------------------------------------------