To support future missions using refuelable spacecraft there is a need to develop a leak-free cryogenic disconnect to enable these propellant transfers. The existing state-of-the-art uses elastomeric seals like Teflon to seal cryogenic interfaces, but based on experience any sealing method based on elastomers is prone to leaking at these extreme cryogenic temperatures.

NASA engaged the GrabCAD community for potential low or zero leakage cryogenic disconnect seal designs that could be fabricated and tested.The project calls for innovative seal designs that can support a cryogenic fluid flow rate of 10-2000 liters/minute, operate within a temperature range of 20 to 400 K, and withstand pressures up to 7 Bar. A crucial performance metric is a leak rate of ≤ 10-6 sccm GHe across the operational temperature range. Designs must also be robust enough to survive the harsh conditions of space and launch environments, including vacuum, radiation, dynamic vibration, and acoustics. Compatibility with robotic handling and the ability to endure multiple connect/disconnect operations are essential. Dimensional constraints include a maximum connected length of 200mm, an outside diameter of 120mm, and a flow diameter between 25-50mm.

NASA encourages the exploration of advanced materials and design concepts, particularly those that account for material coefficients of thermal expansion and consider alternatives like shape memory metals to enhance seal integrity. This project directly addresses critical technology shortfalls related to in-space and on-surface cryogenic fluid transfer and surface mating mechanisms, as identified in NASA’s technology shortfalls list. The Cryogenics Group at Kennedy Space Center, with its extensive experience in cryogenic fuel loading, is actively seeking novel solutions to improve existing components and facilitate future deep-space exploration endeavors.

This project provided NASA with a range of innovative cryogenic disconnect seal designs, addressing critical limitations in current technology. Key benefits include the exploration of novel sealing concepts (liquid metal, shape memory alloys, solder melting), compact and efficient designs, and a focus on robust performance in extreme environments. The submissions offer a strong foundation for developing reliable, low-leakage disconnects for future in-space refueling capabilities.