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FINDINGS AND RECOMMENDATIONS research results into engineering data. Real gas reaction and recombination rates for all constituents and flight conditions are required. Many of these rates are known at low tem- peratures and extrapolation to higher temperatures appear to be within reach of computational chemistry. 13) We recommend a national integrated program of high priority to provide these rates for inclusion into CFD computations. The NASA Ames Group provides a key nucleus for such an effort. 3.5 Controls, Guidance, Instrumentation and Information Processing 9) 1) No successful hypersonic engine or airframe will be possible without multi- redundant, multi- effecter active control of aircraft rigid, structural, and slosh modes; aircraft and propulsion system; and thermal effects. 2) Information and controls must join aerodynamics, structures, materials, and propulsion as a central and enabling technology 3) Control challenges for hypersonic aircraft are well beyond any previous accomplishments, in terms of overall aircraft and propulsion system integration, in the required precision, and at subsystem levels (e.g., engine, thermal) 4) Very high throughput, fault-tolerant control is essential to meet the unprecedented combined require- ments for throughput and reliabil- ity. 5) Essential hypersonic flow sensors for airplane and engine controls do 61 not exist. 6) Control actions have the potential to reduce the sensitivity of engine characteristics to uncertainties and fluctuations, however just what to control, either directly or as a surrogate, to achieve these benefits is not well known, and appropriate sensors may not be available now. The hypersonic thermal environment challenges the capability of existing electronic and hydraulic technology. S) A phased flight program, with asso- ciated phased flight control system configurations that gradually work up the speed envelope, is necessary to reduce controls risks. Three parallel actions are recom- mended to reduce the risks involved with this technology area: a. b. c. Aggressive technology matur- ation efforts in control system architecture (feedback system structure) and associated analy- sis/synthesis activities to cope with the novel flight, engine, and thermal control needs. System studies into hardware and software as needed to assure the availability of adequate controls and · - assoclatec . equipment. Efforts to define earlier (than X-30 flight) experiments that can be done to at least par tially validate the equipment and techniques prior to com mitment to hypersonic flight. Flight tests at lower speeds on other aircraft should be con sidered a well as laboratory and simulation-based testing. These actions should focus on all aspects of control: subsystem control, integra- tion of systems, reduction of sensitiv- ities, control/information system archi
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