Proceedings Article | 5 March 2003
KEYWORDS: Telescopes, Space telescopes, Calibration, Observatories, Stars, Sensors, Helium, Space operations, Cryogenics, Sun
The Space Infrared Telescope Facility (SIRTF) observatory is an 85-cm telescope with three cryogenically cooled instruments. Following launch, the observatory will be initialized and commissioned for routine operations during a sixty-day period called In-Orbit Checkout (IOC), and a subsequent thirty-day period called Science Verification (SV). The emphasis for the IOC phase is to bring the observatory on-line safety and expeditiously, verify functionality of the instruments, telescope, and spacecraft, and demonstrate that the facility meets level-1 requirements. The emphasis of the SV phase is to characterize the observatory in-orbit performance, demonstrate capability for autonomous operations, conduct early release observations, and exercise the ground systems software, processes, and staffing sufficiently to commission the facility for routine operations.
The design of the IOC/SV phases is dominated by two unique features of the SIRTF mission: the solar orbit that affects the thermal design and the communications strategy, and the warm launch architecture whereby the telescope is outside the cryostat and radiatively cools in deep space. The key challenges of SIRTF are in the areas of optical, cryogenic, and pointing control performance, which have dependencies on the performance of the three instruments, and vice versa. In addition, the mission and science operations teams must face the challenge of operating a new space observatory and safely establishing autonomous operations in a very short time. This paper describes a nominal mission plan that progressively establishes SIRTF capabilities during the IOC/SV phases, taking into consideration thermal, cryogenic, optical, communications, celestial mechanics, and operational designs and constraints.
