Propulsion Concept for a Lunar Transportation System Based on In-Situ Propellant

Kurzfassung

Most of the more ambitious scenarios for future lunar utilisation, which include a manned lunar outpost or base, rely on In-Situ Resource Utilization (ISRU) capabilities to support the lunar infrastructure with construction material, fuel etc. The abundance of oxygen on the moon (over 40% of the elemental composition of the lunar soil, collected by the Apollo and Luna missions, is oxygen) allows for engine concepts relying on oxygen as primary propellant. For those reasons, the baseline propulsion concept in this paper assumes oxidizer rich engine operation. This paper analyses and compares dierent propulsion concepts capable of fullling the long range transportation needs of a future moon base. The baseline propulsion concept is a chemical motor using storable Unsymmetrical Di-Methyl Hydrazine (UDMH) and lunar oxygen. The engine uses for simplicity a pressure fed cycle. The ceramic injector has deep throttling capability. The chamber walls are transpiratively oxygen cooled ceramic walls. This paper addresses near term feasibility of the engine concept, based on technology currently under development at the German Aerospace Center (DLR). A Trade-o for the engine mixture ratio is presented in terms of performance and supply cost for lunar operations. Alternative concepts discussed in this paper include dierent propellant combinations for chemical propulsion, as well as a comparison with advanced propulsion concepts, such as nuclear propulsion and Beamed Energy Propulsion (BEP).