Vented Tank Resupply Experiment Demonstrated Vane Propellant Management Device for Fluid Transfer

The Vented Tank Resupply Experiment (VTRE) flown on STS-77 confirmed the design approaches presently used in the development of vane-type propellant management devices (PMD) for use in resupply and tank-venting situations, and it provided the first practical demonstration of an autonomous fluid transfer system. All the objectives were achieved. Transfers were more stable than drop tower testing indicated. Liquid was retained successfully at the highest flow rate tested (2.73 gal/min), demonstrating that rapid fills could be achieved. Liquid-free vents were achieved for two different tanks, although the flow rate was higher for the spherical tank (0.1591 cu ft/min) than for the tank with a short barrel section (0.0400 cu ft/min). Recovery from a thruster firing, which moved the liquid to the opposite end of the tank from the PMD, was achieved in 30 sec, showing that liquid rewicked more quickly into the PMD after thruster firing than pretest projections had predicted. In addition, researchers obtained great insights into the PMD behavior from the video footage provided, and discovered new considerations for future PMD designs that would not have been seen without this flight test.