MARS-EXPRESS Measured CK file by ESA SPICE Service
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   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
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   This file contains orientation and angular velocity data for the
   MARS-EXPRESS spacecraft frame, 'MEX_SC_REF', relative to the Earth
   Mean Equator and Equinox of J2000, 'J2000'. The NAIF ID code for
   MEX_SC_REF is -41001
 
 
Approximate Time Coverage
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   See section "MSOPCK Setup Parameters and Run-Time Traceback" below.
 
 
Status
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   This kernel is an operational product of the MARS-EXPRESS
   Science Operations Team. It is intended to be used by MARS-EXPRESS
   Instrument Teams and scientists for data analysis.
 
 
Pedigree
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   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 MARS-EXPRESS Science Operations
   Team.
 
 
Usage
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   This file should be used together with the kernel set
   described below:
 
     NAIF0012.TLS
                                  is a Leapseconds Kernel file used
                                  in conversions between ephemeris time
                                  and UTC (coordinated universal time).
 
     MEX_170831_STEP.TSC
                                  is the official Spacecraft Clock Kernel
                                  file used in conversions between the
                                  MEX time and ephemeris time.
 
     MEX_V12.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
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   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 intervals. The intervals 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 interval is defined and no interpolation is
   performed in between those intervals 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.
 
   Please note that the current CK incoroporate Angular Rates made-up by MSOPCK
   using the parameter 'MAKE_UP/NO AVERAGING' in the configuration. If this
   parameter was not present the CK would not be usable by any high level SPICE
   interfaces that compute state vectors (6x) or state transformation
   matrices (6x6).
 
 
References
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   [1] CK Required Reading
 
   [2] SCLK Required Reading
 
   [3] TIME Required Reading
 
   [4] MSOPCK User Guide
 
 
Contact Information
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   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
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