Description: Refueling of liquid propellants in microgravity is the key enabling technology to using existing launch vehicles for long-distance spaceflight, such as delivery of large payloads to the Moon. A key challenge for refueling cryogenic propellants in space is the acquisition of vapor-free liquid propellants from the supply tank and subsequently transferring to the receiving tank of a spacecraft. There is currently no flight-qualified cryogenic screened-channel Liquid Acquisition Device (LAD). Screened-channel LADs are highly advantageous for flight cryogenic systems with high demand flow rate. Compared to vane-type propellant management devices, which excel in stabilizing the liquid distribution, the presence of the gas barrier screen in screened-channel devices allows for relatively higher flow rates under more adverse accelerations and promotes higher resistance to gas ingestion. We propose a hybrid LAD incorporating both types of features. Creare’s technology forms a flow channel from screen material itself, allowing much higher acquisition surface area per unit volume compared to existing designs. The hybrid capillary structure positions the residual liquid in the tank to optimum locations to maintain liquid supply for LAD screen surfaces and thus enhance the expulsion efficiency. In Phase II we developed laboratory-scale hybrid LAD structures and evaluated their performance under LN2 outflow conditions, including square-duct screened channels and a cylindrical screened sump. We then designed a full-scale deliverable assembly, which is currently in the final stages of fabrication, scheduled for delivery to NASA at the end of June 2021. This proposed Phase II-E effort is aimed at characterizing LAD performance in microgravity aboard a series of parabolic flights. The proposed technical work scope is crucial to advancement of this technology by bridging the development gap, which will then enable infusion into commercial cryogenic propellant transfer systems.

Benefits: The technology developed in this project will enable reliable cryogenic propellant transfer with high expulsion efficiency in a microgravity environment. This is a critical need for upcoming systems in development as part of the Artemis program, including cryogenic fuel depots and Appendix H in-space lunar ascent and descent stages. The technology also has applications as phase separators in two-phase bio and chemical reactors, as well as for fluid management for two-phase flow thermal control and Rankine power systems.

The technology has applications in propellant acquisition systems in commercial launch vehicles for long-distance spaceflight and has benefits on a smaller scale by extending the life of satellites in low Earth orbit. DoD applications include gravity-insensitive phase separator for aircraft fuel supply systems and for two-phase thermal control.