FLIGHT PERFORMANCE OF THE SHOOT LIQUID ACQUISITION DEVICES

The Superfluid Helium On-Orbit Transfer (SHOOT) Flight Demonstration, launched on STS-57 in June 1993, demonstrated the technology required for the management and transfer of superfluid helium in low gravity, a nd was the first orbital experiment using liquid acquisition systems w ith cryogens. Its primary experimental objective was to test the perfo rmance of two different liquid acquisition devices (LADs) which use su rface tension forces to gather the liquid and feed it to the superflui d pumps. One system consists of c-channels whose open sides are covere d by fine mesh screens which face the tank walls. The other consists o f a series of Mylar(TM) Vanes which extend radially from the centre of the tank. Several superfluid transfers were performed during relative ly quiescent periods and during two transfers adverse orbiter accelera tions of 0.034 and 0.069 m s-2 (3.5 x 10(-3) and 7.0 x 10(-3) g) were generated to move liquid away from the pumps to test the ability of ea ch LAD to work against relatively large hydrostatic heads. Discrete li quid/vapour discriminators placed strategically within the tanks were used to detect failure of the LADs to supply liquid to the pumps. One goal was to test whether, if such a failure occurs, the transfer proce ss can spontaneously recover without operator intervention. Overall pe rformance of both LADs during transfers with and without adverse accel erations is presented.