An overview of NASA efforts on zero boiloff storage of cryogenic propellants

An Overview of NASA Efforts on Zero Boiloff Storage of Cryogenic Propellants2001 Space Cryogenics WorkshopJuly 12-13,2001L.J. HastingsNASA Marshall Space Flight CenterMarshall Space Flight Center, ALe-mail: leon.hastings @ msfc.nasa.govD.W. PlachtaNASA Glenn Research CenterCleveland, OHL. Salerno and P. KittelNASA Ames Research CenterMoffett Field, CAAbstractFuture mission planning within NASA has increasingly motivated consideration of cryogenicpropellant storage durations on the order of years as opposed to a few weeks or months. Furthermore,the advancement of cryocooler and passive insulation technologies in recent years has substantiallyimproved the prospects for zero boiloff storage of cryogenics. Accordingly, a cooperative effort byNASA's Ames Research Center (ARC), Glenn Research Center (GRC), and Marshall Space FlightCenter (MSFC) has been implemented to develop and demonstrate "zero boiloff" concepts forin-space storage of cryogenic propellants, particularly liquid hydrogen and oxygen.ARC is leading the development of flight-type cryocoolers, GRC the subsystem developmentand small scale testing, and MSFC the large scale and integrated system level testing. Thermal andfluid modeling involves a combined effort by the three Centers. Recent accomplishments include:i) development of "zero boiioff" analytical modeling techniques for sizing the storage tankage,passive insulation, cryocooler, power source mass, and radiators; 2) an early subscale demonstrationwith liquid hydrogen 3) procurement of a flight-type 10 watt, 95 K pulse tube cryocooler for liquidoxygen storage and 4) assembly of a large-scale test article for an early demonstration of the integratedoperation of passive insulation, destratification/pressure control, and cryocooler (commercial unit)subsystems to achieve zero boiloff storage of liquid hydrogen. Near term plans include the large-scale integrated system demonstration testing this summer, subsystem testing of the flight-typepulse-tube cryocooler with liquid nitrogen (oxygen simulant), and continued development of aflight-type liquid hydrogen pulse tube cryocooler.Keywords: Orbital Cyrogen Storage