ACE Attitude/Orbit Data

Attitude and Orbit Data - Spacecraft attitude, spin rate, position and velocity vectors in J2000 GCI, RTN, GSE, GSM, HS and HSEb COORDINATE SYSTEMS.

Data in GCI and RTN coordinate systems are received daily by the ACE Science Center (ASC) from the ACE Flight Dynamics Facility (FDF) at GSFC. ASC transforms the data into the other coordinate systems mentioned above. The data are reported for the beginning and end of each DSN telemetry pass, and also for the beginning and end of each spacecraft maneuver during a DSN pass. Because the attitude and orbit of the ACE spacecraft change relatively slowly, the FDF does not provide the data on finer time scales.

ASC receives the attitude/orbit data from the FDF at GSFC in the form of ASCII-format reports. ASC sorts, checks and appends the reports to a database in NCSA HDF format, supplementing the J2000GCI and RTN data by transforming the data into other useful coordinate systems. ASC can provide software to users to access the database in order to extract, for example, the spacecraft attitude vector at a given time in a given coordinate system.

Note that the attitude/orbit data are for specific times (spacecraft clock) given in each report. The times reported are at the beginning and end of each DSN pass and at the beginning and end of each spacecraft maneuver. Data for intermediate times are calculated by interpolation.

NOTE! Interpolation of attitude/orbit data during periods when spacecraft maneuvers are taking place may not be appropriate. Check the ACE maneuvers database for maneuver periods and periods of high nutation after maneuvers.

Accessing ACE Attitude/Orbit Data

The Attitude and Orbit Vectors are available in a HDF format database. The database file is called ACE_ANCIL.HDF. This HDF file contains all the attitude/orbit and clock calibration reports received by ASC to date and is updated daily. There are two ways to access the data:

Last Updated: 23 May, 2013
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