Experimental Performance of Model Liquid Hydrogen Space Tankage with a Compressible Super Insulation

Model tankage for a space vehicle has been insulated with a compressible super insulation enclosed within a vacuum tight flexible plastic shell. To simulate the prelaunch condition, the 9 ft long model has been tested with liquid hydrogen in its propellant tank, and the insulation system compressed by an external load of 1 atm. The thermal conductivity of the compressed insulation was 47 × 10^-5 Btu/hr ft deg R, a value generally considered better than required. Simulation of space conditions resulted in substantial recovery of the normal uncompressed insulation performance. Data are included concerning the evacuation of the insulation and recovery of the insulation system. Temperature measurements in the vicinity of the intermediate bulkhead of this two-compartment tank are included.