Heat rejection concepts for special flight phases of manned space planes like Hermes

Candidate design trade-offs for the evaporation of expendable fluids on the Hermes space plane are evaluated to find an applicable design for the Active Thermal Control System heat rejection assembly. The design criteria and requirements are defined. The concepts tested include the vane operator and a trap operator, in which the flat plates of the vane evaporators are substituted by a bundle of tubes bent so that they block the direct flow area for the two-phase evaporant flow in parallel directions. In addition, experiments are conducted to test a transpirator system.