Novel extraterrestrial processing for space propulsion

The concept of space processing of chemicals, in general, and propellants, in particular, is explored quantitatively. The theoretical parametric calculations are supplemented by a bench scale experiment. It is seen that for several candidate space mission scenarios (recommended by several committees for the near-term future, i.e. 1990–2000 A.D.), space processing of both space resources and Earth-carried resources can make decisive differences in the mission success for a given payload. To fix ideas and to demonstrate trends, the specific case of water splitting to extract oxygen, discard (or use without storage) the resulting hydrogen, and burn Earth-carried non-cryogenic liquid fuel(s) in a simple rocket motor, designed for periodic thrusting, is treated in some detail. Experimental hardware is assembled and demonstrated to perform adequately, besides showing compactness of the space-packaged “capsule” module that is self-contained.Building upon previous studies (Ash et al., IAF-82-210, 1982), the concept of in situ propellant production (ISPP) is reexamined in light of more recent energy and materials technologies. Missions to comets and Mars Sample Return are mentioned as candidate scenarios. The mission duration, reliability-repairability of hardware, resource availability in low Earth orbit (LEO), and the thrust requirements are considered in turn. It is seen that space storage of hydrogen for extended durations (5–10 years) involves problems that require detailed studies, besides involving many presently unanswered issues. A study of the energy option in LEO and in deep space is developed in simple terms. The different solar, radioisotope, and nuclear power sources are mentioned. Storage and handling of raw and processed chemicals are considered.Applications of state-of-the-art technologies are explored using a concept of incremental small steps; this approach would decrease risk and cost yet lead toward fully autonomous energy -processing hardware for future missions. Operations in microgravity and large structure behavior are also mentioned. The paper ends with a brief summary of available options, influences of possible future technologies and breakthroughs, and an examination in light of possible future (beyond 2000 A.D.) missions.