PHARO—Propellant harvesting of atmospheric resources in orbit

Collection and storage of propellant on-orbit has the potential to dramatically reduce launch mass for future exploration missions. A proposed method for this collection utilizes an orbiting vehicle that collects ambient air at a high altitude and uses a fraction of the air for orbital maintenance while storing the remainder for exploration propellant. The derivation of the relations governing propulsion requirements of thrust and specific impulse is presented. Initial requirements for the collector are defined through design maps based on a notional Mars mission.