Flight Reentry Experiments

Reentry technology has long depended on the simulation provided by wind tunnels, shock tubes, arc jets, and a variety of other ground facilities to advance the experimental verification of the results predicted from theory or postulated empirically from previous tests. As the application of information thus obtained approaches the point of application to the design of flight systems, the question of the extent to which the information can he applied with confidence inevitably arises. Sources of uncertainty are the assumptions necessary to obtain theoretical solutions, the inadequacy with which the complex reentry environment can be totally simulated on the ground, and the question of how well the ground facility results have been validated by flight comparisons. Thus the value of flight reentry testing is greatest when the tests either explore the nature of a phenomenon, difficult or impossible to simulate on the ground, or provide the validation for use of a system or concept developed from ground-based research.