Three of the key abilities needed for making future NASA and commercial in-space transportation systems more affordable and capable are: a) the ability to �live off of the land� via in-situ resource utilization (ISRU), b) the ability to reuse in-space transportation hardware, and c) the ability to leverage continuing advancements in lower-cost earth-to-orbit transportation. All of these abilities require the ability to transfer large quantities of cryogenic liquids (Oxygen, Hydrogen, and Methane) between tanks on separate vehicles. In this proposed SBIR research effort, Altius Space Machines proposes the development of a lightweight, high-flow cryogenic propellant coupling to enable such bulk propellant transfers. This coupling incorporates an innovative new cryogenic sealing architecture to enable a coupling with very low insertion/extraction forces, for both robotic and Astronaut-connected cryogenic propellant transfer operations. In Phase I, Altius and its team will focus on developing and testing a proof-of-concept of this innovative new cryogenic sealing architecture, including performing insertion/extraction and leak testing, to compare with a more traditional spring-energized polymer seal concept. Altius will then update the coupling design based on lessons learned-from these tests, raising the TRL from 2 to 3 at the end of Phase I.