MESSENGER Propulsion System: Strategies for Orbit-Phase Propellant Extraction at Low Fill Fractions

摘要

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission was designed to unlock the secrets of our solar system's innermost planet, revealing clues to the planet's enigmatic geological history, unusually high density, and radar-reflective materials at the poles, among many other decades-old unanswered questions. MESSENGER began its journey on 3 August 2004, when it was launched from the Cape Canaveral Air Force Station in Florida, and the spacecraft was successfully inserted into its destination orbit about Mercury on 18 March 2011. After expending the vast majority of its propellant to reach the planet, the MESSENGER dual-mode propulsion system required a new set of operating procedures to extract the remaining fuel and oxidizer. Those updated guidelines were used to successfully execute five orbit-correction maneuvers during the one-year primary orbital mission. After the completion of the primary mission objectives, an additional one-year extended mission began that required the propulsion system to exhaust all of its remaining usable oxidizer and empty the usable fuel from one of its main tanks. To accomplish this goal, the recently updated propellant extraction techniques had to be further modified to safely deplete the remaining propellant from the near-empty tanks.