XMM-Newton Data Files Handbook

4.1.11.2 Spacecraft Attitude History File

The Spacecraft Attitude History file (*SC*ATS.FIT) contains the attitude data extracted from flight dynamics. A single file is created for the whole revolution, when the observation/slew period occurred. All information is expressed with respect to the mean geocentric equatorial reference system of Equinox J2000.0. Each file consists of a single binary table, whose columns are described in Table 26.

The Spacecraft Raw Attitude History file (*SC*RAS.ASC) contains a subset of the quantities in the Spacecraft Attitude History files, sampled, however, at the maximum possible rate (0.5-1s). Each file (in ASCII format) consists of a single table, whose columns are described in Table 27.

Table 26: Spacecraft Attitude History file (*SC*ATS.FIT) binary table columns

Name	Type$^a$	Units	Description
VALTIME	19A	yyyy-mm-ddThh:mm:ss	Time from which data in this record are valid
VALDUR	1E	SECOND	Duration for which data in this record are valid
OTFTHRES	1E	ARCSEC	On target flag threshold
VIEWRA	11A	HH:MM:SS.S	R.A. of viewing direction
VIEWDECL	11A	$\pm$DD:MM:SS.S	Declination of viewing direction
ASTPOS	1E	DEGREE	Astronomical position angle
ROLLANG	1E	DEGREE	Roll angle
GSREFNO	12A		Guide Star reference number in catalogue
GSRA	11A	HH:MM:SS.S	Guide Star right ascension
GSDEC	11A	$\pm$DD:MM:SS.S	Guide Star declination
ASPANGLE	1E	DEGREE	Solar aspect angle
ACFLAG	1B		Attitude contingency flag
APDAMP	5A	ARCSEC	Observable APD amplitude
DIFFVRA	11A	HH:MM:SS.SS	Difference between reconstructed
			and commanded viewing direction right ascension
DIFFVDEC	11A	$\pm$DD:MM:SS.S	Difference between reconstructed
			and commanded viewing direction declination
DIFFPOS	11A	DEGREE	Difference between reconstructed
			and commanded viewing direction position angle
PREQID	14A		Pointing request identifier
TYPEID	1A		Type identifier
SOURCEID	1A		Source identifier
ATTSEQNO	1A		Attitude sequence number
SLEWTIME	19A	yyyy-mm-ddThh:mm:ss	Start time of slew to the pointing request
PTTIME	19A	yyyy-mm-ddThh:mm:ss	Start time of stable pointing period

$^a$See Sect. 9 for convention

Table 27: Spacecraft Raw Attitude History file (*SC*RAS.ASC) ASCII table columns

Name	Type$^a$	Units	Description
VALTIME	15.9F	MJD2000	Time from which data in this record are valid
REQUESTID	10A		Pointing request identifier
VIEWRA	12.9F	RAD	R.A. of viewing direction
VIEWDECL	12.9F	RAD	Declination of viewing direction
ASTPOS	9.6F	RAD	Astronomical position angle
ASPANGLE	9.6F	RAD	Solar aspect angle
ROLLANG	9.6F	RAD	Roll angle
SUSEFLAG	1A		Sensor usage flag$^b$
POINTYPE	1A		Pointing type identifier$^c$
ATRETYPE	2A		Attitude reconstruction method$^d$

$^a$See Sect. 9 for convention

$^b$``T'' (``F'') indicates that sun solar sensor has (has not) been used for attitude determination

$^c$ ``O'' = open-loop slew; ``C'' = closed-loop slew; ``S'' = settling-period attitude; ``P'' = stable pointing attitude

$^d$ ``MO'' for attitude determination based on a map; ``G$n$'' for attitude determination based on $n$ tracked stars