Systems Engineering Approach Used in the Development of the MESSENGER Propulsion System

Abstract

*† The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission is the seventh in the series of NASA’s Discovery missions. The MESSENGER spacecraft was launched 3 August 2004 and is currently on its trajectory to Mercury. It will spend nearly 7 years en route to the planet. During that time, the spacecraft propulsion system will provide periodic attitude control operations and ΔV burns as commanded by the MESSENGER mission operations team. Upon arrival, the propulsion system will perform an orbit insertion burn and the spacecraft will orbit the planet for one Earth year gathering scientific data. The MESSENGER mission required a low-mass propulsion system capable of delivering approximately 2300 m/s of ΔV that could be provided to The Johns Hopkins University Applied Physics Lab (JHU/APL) in time to meet the launch-date-driven spacecraft integration schedule. Early concept design trades selected a propulsion system that was highly integrated with the spacecraft, used off-the-shelf qualified system components to the greatest extent possible, and included a new missionspecific propellant tank design. To meet the technical and schedule requirements, the MESSENGER propulsion system team used a highly disciplined systems engineering approach founded on an early understanding of the constraints associated with the entire mission. The mission phases evaluated included propulsion system development and test, spacecraft integration and test, launch on a Delta-II heavy launch vehicle, and in-flight operations. This paper describes how the early implementation of systems engineering disciplines resulted in a propulsion system that successfully integrated with the spacecraft, withstood the severe launch environments, provided nutation control during the launch vehicle’s third stage burn, and has completed nearly 2 years of flight operations to date.