ACE Attitude/Orbit Data
- Plots of the ACE trajectory
- Daily ACE position data in GSE coordinate system - ascii text file
- Daily ACE position data in GSE and J2000 GCI coordinate systems - ascii text file
- Hourly ACE attitude data in RTN, GSE and J2000 GCI coordinate systems - ascii text files
- Information on the spin-phase of the ACE spacecraft, and sunpulse-time data
- Access ACE attitude/orbit data via our web-based HDF browser
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:
- ASCII files of position and attitude data extracted from the HDF database - see links at top of this page.
- Spin-phase information and sunpulse data extracted from the Level 1 HDF files - see links at top of this page.
- Access the attitude/orbit data via our web-based HDF browser. You can use this interface to download in ASCII format whatever subset of the data you want. If you like, you can also use this interface to download the complete HDF database and browse it with your own HDF browser.
(C source code) to read and extract data from the HDF database. This software
performs the interpolation necessary to obtain attitude/orbit information
at any desired time.
Documentation of the HDF data structures used in the database is included.
This ftp site also has a copy of the current ancillary HDF data file, and
examples of the raw AOR and CCR reports received from GSFC.
You'll need HDF libraries for your computer architecture to use this package.
- Definitions of all the data items contained in the ACE ancillary database (ACE_ANCIL.HDF).
Last Updated: 23 May, 2013 Return to ASC Home Page