Long Life Cryogenic Propellant Storage in Space by New Compressor-Expander Cycle (CEx-C) System

TransAstra and Southwest Research Institute (SwRI) are developing a cryogenic propellant storage system that will provide a leap ahead in the perennial battle to increase the longevity of cryogenic fluids, such as liquid Hydrogen (LH2), for the use in high-efficiency, high-performance spacecraft missions. This propellant storage architecture uniquely uses an innovative gas-handling technique called a Compressor-Expander Cycle (CEx-C). CEx-C enables long-life missions and on-orbit propellant storage by converting mechanical energy into stored electrical energy, which can be used to power spacecraft feed systems or cryochillers with maximum efficiency. The novel system architecture minimizes reliance on power- and mass-intensive cryochillers and improves the feasibility and viability of cryogenic propellants on-orbit. Early thermal models used to analyze performance in deep space missions using this storage design show lifespans >3 months that would otherwise have <1 month of storage. Our highly efficient cryogenic storage system comprises 7 critical subsystems (details on slide 4). The Compressor Expander Cycle (CEx-C) — the key, novel, subsystem that optimizes energy usage throughout the mission's life on orbit — is TRL 2. During this effort, we will mature CEx-C to TRL 4. Three (3) other subsystems are currently at TRL 4; we will mature these three subsystems to TRL 5/6. This will mature the overall system concept integration readiness level to TRL 4. Our Phase 1 effort consists of 1) customer discovery across the various market applications and 2) determining the most effective approaches to implementing the CEx-C compressor expander loops. In Phase 2, we will prototype and test CEx-C energy recapture systems, design vapor-cooled cryogenic tanks, develop an end-to-end thermal model of the thermal control and feed system, and demonstrate critical components.