Refueling spacecraft in space offers tremendous benefits for increased spacecraft payload capacity and reduced launch cost. A key technology challenge for space refueling is the storage of liquid cryogenic fuel in space. To meet this need, we propose to develop a reliable, compact, efficient cryogenic mixing pump with no moving parts. The mixing pump will prevent thermal stratification of the cryogen and simplify pressure control for storage tanks. The mixing pump uses an innovative thermodynamic process to generate fluid jets to promote fluid mixing, eliminating the need for mechanical pumps. Our innovative mechanism will be able to self-prime and generate a high-pressure rise. The device will significantly enhance the reliability of pressure control systems for storage tanks. In Phase I, we will prove the feasibility of our approach through building and testing a proof-of-concept mixing pump and developing an analytical model to optimize the mixing pump design. In Phase II, we will build and test a laboratory-scale cryogenic mixing pump and demonstrate its performance in a representative cryogenic environment.