SBIR-STTR Award

In-space cryogenic propellant transfer is a key enabling technology for future long duration space exploration missions. However, successfully refueling tankage with cryogenic propellants in space presents significant challenges related to the chilldown of the receiving tank. There is a limited supply of propellant in space depots and the cold propellant itself has to be used for chilldown purposes utilizing non-vented filling procedures while maintaining the pressure in the receiving tank below a prescribed threshold. Although filling protocols such as pulsed-injection and charge-vent-hold have been developed to optimally achieve high fill-levels during the refueling process, the success of attaining high fill refuel levels is largely dependent on the cooling efficiency of the tank walls and the ullage. It is envisioned that tank cooling will be facilitated by spray injection nozzles that remove thermal energy rapidly from the system minimizing boil-off, propellant loss and chilldown time. The innovation described in this proposal is a collaborative effort between CRAFT Tech and the University of Connecticut that involves detailed experimental visualization and diagnostic measurements involving the interaction of spray nozzles with tank environments and utilizing these observations for the development of specialized spray cooling models in a high-fidelity multiphysics simulation framework. Potential NASA Applications (Limit 1500 characters, approximately 150 words) The technology will benefit NASA’s Reduced Gravity Cryogenic Transfer program by providing design support for critical components such as spray injection nozzles and predicting the amount propellant required for chilldown. Cryogenic propellant storage and transfer is critical to nearly all NASA’s future human exploration missions including the imminent Moon Gateway Mission and the more distant Mars Exploration Campaign. The success of these missions is reliant on reliable CFM including protocols for propellant storage and transfer. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words) The technology can be used to support launch activities related to SpaceX’s Falcon Heavy rocket as well as Blue Origin’s New Shepard rocket. Other applications include the design of cryogenic spray nozzles for advanced propulsion concepts. Non-Aerospace applications include the medical applications such as preservation of tissues (surgery) and organs (transplant), to life-support systems.

In-orbit cryogenic propellant transfer is a key enabling technology for future long duration space exploration missions. Tank chilldown will be one of the primary challenges to be overcome to achieve refueling in space. It is envisioned that tank cooling will be facilitated by the use of spray injection nozzles, achieving high heat removal rates through phase change. Tank filling protocols such as charge-vent-hold and vented-chill-non-vented-fill are being investigated to improve the probability of successful refueling while minimizing propellant boil-off. In this collaborative effort between the Univ of Connecticut and CRAFT Tech, experimental visualization and diagnostic measurements of a sub-scale tank are being used to understand the complex heat-transfer interaction modes between the spray and the ullage as well as the spray and the tank walls. Validation datasets are being collected and used in the development of a specialized spray cooling models within a comprehensive high-fidelity Multiphysics simulation framework. The simulation framework can be used for design support, analyzing tank filling protocols and prediction of chilldown times and propellant loss as part of the refueling process in a microgravity environment. Potential NASA Applications (Limit 1500 characters, approximately 150 words) Cryogenic propellant storage and transfer is critical to nearly all NASA’s future human exploration missions such as the Moon Gateway Mission and the more distant Mars Exploration Campaign. Successful propellant transfer in space is the cornerstone of NASA’s Reduced Gravity Cryogenic Transfer program and the technology in this program will impact it by improving our understanding of the physical processes, proving validation datasets and high-fidelity predictive tools. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words) The technology will be valuable in decarbonization efforts and the transition to a hydrogen economy since storage and transfer of hydrogen remains a significant challenge. The technology can also be used for design of cryogenic spray nozzles for advanced propulsion concepts, improving life support systems in space as well as cryogenic preservation techniques in medical applications.