Calibration of in-flight maneuver performance for the THEMIS and ARTEMIS mission spacecraft

Abstract

We describe the development and details of in-flight calibration techniques used to obtain the required degree of accuracy for mission-required, small-scale trajectory adjustments. Using the dynamics data gathered from dozens of orbital-adjustment maneuvers previously conducted on the ARTEMIS and THEMIS spacecraft, the Space Sciences Laboratory (SSL) Flight Dynamics group has systematized a calibration process employing hill-climbing and grid searches for single segment and multi-segment maneuvers, respectively. This effort has resulted in the characterization of a nonlinear function of thruster performance scale factors and offsets to use in NASA Goddard's GMAN software package for maneuver planning and reconstruction. To date, use of these factors has greatly reduced deviations between predicted and observed orbital state vector solutions and spinrate changes following a sequence of orbit-raising maneuvers intended to result in a lunar gravitational capture of the ARTEMIS probes in early 2010. © 2010 by the American Institute of Aeronautics and Astronautics, Inc.