VERIFICATION TESTING OF THE SUPERFLUID-HELIUM ON-ORBIT TRANSFER (SHOOT) EXPERIMENT

The Superfluid Helium On-Orbit Transfer (SHOOT) project is a secondary shuttle cross-bay payload which flew on the STS-57/Endeavour mission. It was designed to develop and demonstrate the technologies required to resupply liquid helium containers in space, and to develop new tech nologies that may be used in other future space cryogenic systems. The SHOOT payload consists of two superfluid helium Dewars with helium ma nagement cryostats connected by a transfer line, and six avionics boxe s for valve and heater control, temperature, pressure and fluid positi on monitoring and data processing and telemetry. The cryostats contain numerous specialized helium management components; including high and low flow phase separators, liquid/vapour discriminators, flowmeters, liquid level detectors, cryogenic mechanical valves and cryogenic reli ef valves and burst discs, and two varieties of fluid acquisition syst ems. To prepare the SHOOT payload for launch a series of functional, s tructural, thermal and reliability tests were conducted at every level of hardware assembly, from materials tests to system level thermal, s tructural and functional performance tests. We present here the verifi cation tests and analyses developed and completed at each level of ass embly. We discuss the trade-offs considered for, and the success (or f ailure) of, models and analyses to predict performance results. Finall y, we present some lessons learned of potential interest to future cry ogenic missions, whether on the Space Shuttle or on expendable launch vehicles.