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Proceedings Paper

Updating Chandra high-radiation safing in response to changing observatory conditions
Author(s): Michael Juda; Mark Baski; Chris Eagan; Jeff Holmes; Sabina Hurley; David Jones; Eric Martin; Harold Rice; Paul Viens; Brent Williams; Daniel Wong
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Paper Abstract

The science instruments on-board the Chandra X-ray Observatory may be damaged by high fluxes of energetic particles produced in Solar storms. For twelve years the on-board commanding used to safe the instruments when a high-radiation environment was identified included stopping all on-board scheduled activity. Over this time the conditions of the observatory have changed: the orbit has evolved to lower perigee and the thermal protective surfaces have degraded. The likelihood of an unplanned unload of spacecraft angular momentum, a spacecraft component exceeding thermal limits, or an eclipse passage without planned commanding occurring following a Solar storm during the upcoming Solarmaximum due to the lack of scheduled commanding led us to update the Chandra response to a high-radiation environment; commands are sent to safe the science instruments but vehicle related commanding (maneuvers, angularmomentum unloads, eclipse commands) are allowed to continue. While this was a conceptually simple change, it touched all elements of the program, including flight software, the planning and commanding systems, flight-load verification tools, and ground-based data processing. A key to successful and timely implementation was the establishment of a working group with representation from all elements of the program.

Paper Details

Date Published: 13 September 2012
PDF: 11 pages
Proc. SPIE 8448, Observatory Operations: Strategies, Processes, and Systems IV, 844805 (13 September 2012); doi: 10.1117/12.940772
Show Author Affiliations
Michael Juda, Harvard-Smithsonian Ctr. for Astrophysics (United States)
Mark Baski, Northrop Grumman Aerospace Systems (United States)
Chris Eagan, Harvard-Smithsonian Ctr. for Astrophysics (United States)
Jeff Holmes, Northrop Grumman Information Systems (United States)
Sabina Hurley, Northrop Grumman Aerospace Systems (United States)
David Jones, Northrop Grumman Aerospace Systems (United States)
Eric Martin, Northrop Grumman Aerospace Systems (United States)
Harold Rice, Harvard-Smithsonian Ctr. for Astrophysics (United States)
Paul Viens, Northrop Grumman Aerospace Systems (United States)
Brent Williams, Northrop Grumman Aerospace Systems (United States)
Daniel Wong, Northrop Grumman Aerospace Systems (United States)


Published in SPIE Proceedings Vol. 8448:
Observatory Operations: Strategies, Processes, and Systems IV
Alison B. Peck; Robert L. Seaman; Fernando Comeron, Editor(s)

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