Compressor for Efficient On-Orbit Gas Transfer

Transfer of gaseous propellant in space is a critical technology for space exploration and for extending the useful life of satellites. A key component needed for in-space refueling is a compressor that can efficiently move gas from a resupply vehicle to the propellant storage vessel on board the receiver vehicle. High efficiency requires a very high pressure ratio, and operation on orbit requires that the compressor be compact, lightweight, and space worthy. We propose to develop a compact, high-pressure ratio compressor that meets these requirements. Our technology can efficiently transfer gas from a low-pressure supply vessel to a high-pressure receiver vessel using a highly reliable compression mechanism. In Phase I, we proved feasibility through demonstration testing of key components and materials, analysis and assessment of key design trade-offs, detailed conceptual design, and predictions of performance. In Phase II, we will build a prototype compressor and demonstrate operation under conditions that simulate propellant transfer in space. Relevance. NASA needs a way to compress gas in space to refuel the Gateway space station and enable transfer and management of cryogenic propellants. Commercial and defense satellite operators need refueling capability for gaseous propellants and pressurants to extend satellite operating life, reduce costs, and enhance capabilities. A compact, efficient, high-performance, and space-worthy compressor is required to fill this critical technology gap. Innovation. Creare proposes to develop an innovative high-pressure-ratio compressor. Our compressor transfers gas by positive displacement using an innovative drive system that is well-suited for space service. Our approach provides very low dead volume and high compression ratios, and proper design of critical components allows for essentially infinite lifetime. Near-isothermal compression minimizes mechanical power requirements. The compressor is a modular system, in which identical compression modules can be arranged in series and parallel to meet flow rate and pressure ratio requirements for a range of applications. Objectives. The overall objective is to enable efficient, on-orbit transfer of gaseous propellant. The approach is to develop a compact, high pressure ratio compressor using Creare’s innovative, highly reliable technology capable of compressing supercritical xenon, krypton, and helium, and other gases. Target performance objectives for a flight compressor are: (1) compress low-pressure fluid up to 3,000 psia with continuous flow of up to 15 g/s; (2) operating with an inlet gas temperature of 17°C to 40°C; (3) surviving launch-load vibrations; (4) functioning accurately in microgravity and vacuum environment (10 to 5 torr); and (5) maintaining gas cleanliness to Level A/10 for nonvolatile residue. The specific objective in Phase II is to design, build, and demonstrate operation of a prototype compressor that is half-scale relative to the full-size Gateway refueling compressor. Because our system is modular, future units can incorporate twice as many compression modules to meet the Gateway requirements. Deliverables. We plan to deliver the half-scale prototype to NASA at the conclusion of Phase II, along with a final technical report, invention reports, and other paper deliverables.
Benefits: NASA’s primary application is propellant transfer for space exploration. Resupply of xenon propellant for the Gateway space station will ultimately be developed by the Gateway Program and the Gateway Logistics Program Office. Transfer of helium pressurant gas for management of cryogenic propellant can support the recent Tipping Point programs awarded for cryogenic fluid management and managed through NASA’s Glenn Research Center, Marshall Space Flight Center, and Kennedy Space Center. The main commercial application is refueling with gaseous propellant or recharging helium pressurant to extend satellite life, reduce costs, and enhance capabilities. Customers will be companies that build and operate spacecraft for in-space servicing, assembly, and maintenance of orbiting spacecraft. These companies include new commercial ventures as well as established aerospace primes.