Integration and test of the EO-1 reaction control system

Abstract

The NASA New Millennium Program (NMP) Earth Observing-1 (EO-1) spacecraft was launched in November 2000 on its primary mission to validate advanced remote sensing instruments. A critical requirement for flying technology with respect to the LandSat-7 for instrument image comparison dictated the inclusion of a propulsion system. Instrumental in the success of the EO-1 project was a comprehensive test program designed to validate the proper operation of all spacecraft components. In the case of the EO-1 Reaction Control System (RCS) design for testability included consideration of the entire RCS life cycle. The EO-1 RCS design incorporated features, which allowed extensive spacecraft level testing, as well as RCS unique tests as required by Range Safety. This paper details the EO-1 RCS design features, which aided in spacecraft level testing, the design details of the ground support equipment used, and the lessons learned from this project. Introduction The goal of NASA's New Millennium Program (NMP) is to identify, develop, and perform validation of key breakthrough technologies. Future spacecraft can then take advantage of these technologies without assuming the risks inherent in their first use. The NMP technology development and validation process will also provide a significant return of valuable science data. Thus the NMP flights offer immediate benefits to the scientific community, in addition to a steady stream of breakthrough technologies for future science missions. The EO-1 mission is one of the first in the NMP series of smaller, faster, and cheaper Earth observing spacecraft. NASA's Jet Propulsion Laboratory manages the NMP, while Goddard Space Flight Center has responsibility for the EO-1 mission. The Goddard Space Flight Center awarded Swales Aerospace the prime contract for the EO-1 spacecraft. The EO-1 spacecraft was launched from Vandenberg Air Force Base on November 21, 2000 into a circular, sun-synchronous polar orbit at an altitude of 705 kilometers. EO-1 was co-manifested on a Boeing Delta II launch vehicle with the SAC-C satellite developed by Argentina. The EO-1 orbital inclination (98.2 degrees) and descending nodal crossing time puts it in formation flight with Landsat-7 and EOS-AM (Terra). With all three satellites following the same ground track, EO-1 is flying behind Landsat-7 but ahead of EOS-AM (Terra). Due to the aspect of the mission, the EO-1 spacecraft required the capability for orbit adjustment maneuvers as well as precision orbit maintenance.