Mission demonstration concept for the long-duration storage and transfer of cryogenic propellants

This paper describes an experimental platform that will demonstrate the major technologies required for the handling and storage of cryogenic propellants in a low-to-zero-g environment. In order to develop a cost-effective, high value-added demonstration mission, a review of the complete mission concept of operations (CONOPS) was performed. The overall cost of such a mission is driven not only by the spacecraft platform and on-orbit experiments themselves, but also by the complexities of handling cryogenic propellants during ground-processing operations. On-orbit storage methodologies were looked at for both passive and active systems. Passive systems rely purely on isolation of the stored propellant from environmental thermal loads, while active cooling employs cryocooler technologies. The benefit trade between active and passive systems is mission-dependent due to the mass, power, and system-level penalties associated with active cooling systems. The experimental platform described in this paper is capable of demonstrating multiple advanced micro-g cryogenic propellant management technologies. In addition to the requirements of demonstrating these technologies, the methodology of propellant transfer must be evaluated. The handling of multiphase liquids in micro-g is discussed using flight-heritage micro-g propellant management device technologies as well as accelerated tank stratification for access to vapor-free or liquid-free propellants. The mission concept presented shows the extensibility of the experimental platform to demonstrate advanced cryogenic components and technologies, propellant transfer methodologies, as well as the validation of thermal and fluidic models, from subscale tankage to an operational architecture.