Abstract: A centrifugal propellant depot positioned in outer space for storing and transferring cryogenic liquid propellants to and from transfer space vehicles which are adapted to transport cryogenic liquid propellants to the depot to receive the liquid propellants stored in the depot. The depot includes a plurality of contra-rotatable torus-shaped hollow storage tanks adapted to receive cryogenic liquid oxygen and hydrogen propellants that are carried in gas/liquid phase separation by rotational gravity. Transport rail members transversely bridge the storage tanks. A central docking hub is coupled to the transport rail members and disposed centrally of the rotating storage tanks. The docking hub may receive a transfer space vehicle on either of two opposing sides of the hub for transfer, via a transfer vehicle coupled to the rail members, outwardly to the storage tanks.