Developed for the GLAST project, which is now the Fermi Gamma-ray Space Telescope, GlastCam software ingests telemetry from the Integrated Test and Operations System (ITOS) and generates four graphical displays of geometric properties in real time, allowing visual assessment of the attitude, configuration, position, and various cross-checks. Four windows are displayed: a “cam” window shows a 3D view of the satellite; a second window shows the standard position plot of the satellite on a Mercator map of the Earth; a third window displays star tracker fields of view, showing which stars are visible from the spacecraft in order to verify star tracking; and the fourth window depicts Sun sensor measurements, enabling verification of the solar array deployment state. Each of these windows has telltales showing useful information applicable to each window, such as spacecraft axes, magnetic field vectors, the Sun-pointing direction, and the like. These can be toggled on or off as desired. By breaking up the data into applicable windows, it is easier to monitor specific data of interest. Because the displays operate in real time and visually, any changes to the spacecraft’s configuration or attitude are seen immediately. This allows for fast and intuitive spacecraft geometry assessment.

This work was done by Eric T. Stoneking and Dean Tsai of Goddard Space Flight Center. GSC-15572-1

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This article first appeared in the September, 2009 issue of Software Tech Briefs Magazine.

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