An experiment to demonstrate key cryogenic technologies for solar thermal rockets

This paper discusses the design of a small experiment called Hydrogen On-orbit Storage and Supply (HOSS). The objectives of the experiment are: Show stable gas supply for storage and direct gain solar-thermal thruster designs; and evaluate and compare low-g performance of active and passive pressure control via a thermodynamic vent system (TVS) suitable for solar-thermal upper stages. This paper shows these can be done with a 149 kg spacecraft. This spacecraft is suitable for launch on a low cost launch vehicle. Other topics include the following: Background of cryogenic fluid management efforts; unique requirements of cryogenic fluid management for solar-rocket; how these requirements are met in a small scale experiment.