Sierra Lobo has 17 years of experience with cryogen storage for UUVs, beginning in 2001 with a Small Business Technology Transfer contract to develop oxygen storage funded by the Office of Naval Research. This was followed by development of power systems for 21- and 42- inch diameter UUVs, which included storage and delivery of both liquid oxygen and liquid hydrogen to fuel cells. Sierra Lobo’s designs meet the demands of UUV operation and have the low boil-off rates necessary for long duration missions.