A report proposes a system that would supply gas for inflating one or more inflatable structure(s) in outer space. The system would include a small tank of helium for initial inflation, plus a catalytic hydrazine gas generator that would supply makeup gas over the long term. After initial inflation, when makeup gas was needed, liquid hydrazine from a tank would be made to pass through a catalytic bed, where it would become decomposed into a mixture of N2, H2, and a small amount of NH3. This gaseous mixture would constitute the makeup gas and would be stored in the tank that previously contained the helium. The makeup gas would be released from the tank to the structure(s) as needed. In comparison with an inflation system based only on compressed gas stored in tanks, the proposed inflation system would offer the advantage of lower mass: About 25 percent of the masses of representative previously contemplated large inflatable outer-space structures would have been contained in their inflation systems. In contrast, the mass of the proposed inflation system has been estimated to be only about 13 percent of the total mass of a representative structure.
This work was done by Larry Roe of Caltech for NASA's Jet Propulsion Laboratory. To obtain a copy of the report, "System For Initial Inflation and Replacement Gas For Inflatable Space Structures," access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Mechanics & Automation category.