A Liquid Hydrogen Dewar to Supply Gas to Balloons in Flight

Abstract

In order to obtain meteorological data at altitudes up to 100,000 feet, is is necessary to maintain large balloons at a constant operating altitude for periods of several days at a time. A representative balloon is 128 ft. diameter by 200 ft, high with a displaced volume of 3/4 million cubic feet and for a 10-day flight time requires a ballast load of 1,000 pounds (which is 30 to 40% of the gross load of the balloon. During the day, gas inside the balloon expands and is exhausted from the balloon. At sunset, the gas contracts, which decreases the lift of the balloon and would result in the balloon’s descent unless counteracted. The present method of counteracting these effects is to drop ballast overboard in order to decrease the load and maintain the balloon at a constant altitude. Because of the weight of ballast required, the possibility of supplying gas to the balloon from a liquid hydrogen dewar or high pressure container was investigated.

This work was performed for the Air Force Cambridge Research Center Geophysics Research Directorate Contract AF 19 (604)-1417 CRHD.