LRO Propulsion System Design On-Orbit Operations

摘要

The Lunar Reconnaissance Orbiter (LRO) is a robotic exploration observatory launched on June 18, 2009. The LRO spacecraft contains a monopropellant propulsion system with twelve thrusters, two propellant tanks, a composite overwrapped pressurant tank, and fluid control hardware to regulate the propellant supply to the thrusters. This paper provides a detailed discussion of the propulsion system design, which was driven by a fast-paced schedule and thus needed to utilize existing components. The LRO launch vehicle placed the spacecraft into a direct transfer orbit to the Moon; the propulsion system operated to capture lunar orbit, transfer to the low polar orbit for mission operations, and maintain the mission orbit for a one-year mission. The system is a pressure-regulated monopropellant hydrazine system with modularity that allowed propulsion system assembly in parallel with spacecraft assembly. This paper discusses the fluid schematic including component descriptions and rationale and describes the mechanical, thermal, and electrical design implemented for LRO. This paper ends with a discussion of the on-orbit propulsion system performance, including system priming operations while traveling to the Moon, orbit insertion maneuvers to establish the mission orbit, orbit maintenance maneuvers for the nominal mission life, and maneuvers required for the extended mission.