ACHIEVABLE FORCE MODEL ACCURACIES FOR MESSENGER IN MERCURY ORBIT

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission is the seventh mission in NASA's Discovery Program. The spacecraft, launched from Cape Canaveral Air Force Station in August 2004, arrived in orbit about Mercury in March 2011 to begin a one-year scientific investigation. While in orbit, the spacecraft is subject to a variety of forces, including Mercury and solar gravity, solar and planetary radiation effects, and propulsive events associated with orbit correction and momentum desaturation. This paper describes the challenges for navigation in terms of achieving the highest accuracy possible for relevant force models to support orbit determination and reconstruction over the Mercury orbital phase of the MESSENGER mission.