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HYPERVELOCITY TECHNOLOGY (HVT) CREW ESCAPE

Lanny A. Jines, P.E. Engineer Air Force Wright Aeronautical Laboratories Flight Dynamics Laboratory Crew Escape and Subsystems Branch Air Crew Escape Group WPAFB, OH 45433

ABSTRACT The Flight Dynamics Laboratory is Appropriately, the escape systems for such currently conducting a research and development vehicles will require an expanded flight effort investigating conceptual designs for envelope when compared to the existing escape escape systems applicable to hypervelocity system performance envelopes of current military technology class aerospace vehicles. The . Presently, open ejection seats contractor, Boeing Military Airplane Company, provide inadequate performance for has recently completed Task I, Concept hypervelocity class vehicles. The ejection Definitions and Preliminary Evaluation; and Task trajectory range is cannot prorjde for safe 11, Enabling Technology Identification; of escape from the launch pad or for the initial contract F33615-86-C-3410 (Reference 1). The phase of ascent. State-of-the-art open ejection concepts selected for further development seats are also inadequate for high speed or high through out the effort will provide survivable altitude escape conditions. During a seven (7) escape and recovery throughout all phases of year period from 1973 to 1979, the statistics flight including launch, upper atmospheric from non-combat ejections of open ejection seats hypervelocity, orbit, atmospheric entry, at airspeeds between 400 and 500 keas showed terminal approach, and landing. The specific that 57% of the crew members sustained major or objective for Task I was to conduct conceptual fatal injuries. From 500 to 60C KEAS, the major development of the candidate escape system injury and fatality rate was approximately 70% concepts which meet the various crew escape and and above 600 KEAS, the probability of major or protection requirements. The contractor fatal injury was 100% (Reference 4,p.27). initially identified sixteen (16) conceptual Pressurization is required for protection when escape systems. Of the sixteen, there were two ejection occurs above 50,OUC fret altitude. viable options. The study vehicles Included a Attempts to provide emergency escape capability horizontally launched vehicle (HLV) and a for high velocity atmospheric aircraft has led vertically launched vehicle (VLV). The to the development of enclored ejection seat contractor has developed graphic computer aided escape systems (B-58) and B-70) and crew escape design models of the candidate escape systems modules (F-Ill and prototype PI). The problems with Zenith 248 computers utilizing the CADC ITc posed by these types of escape system have software package (Reference 2). During Task II been: accelerations imposed on the crew durjng the contractor has identified the necessary separation from the aircraft and upon landing state-of-the-art or near-term enabling impact, increased time to full recovery technologies; i.e., propulsion, life support, inflation due to larger recovery thermal protection, deceleration, etc.; that parachute systems, weight penalty, and high life would allow for the implementation of the cycle costs. Various concepts and technlques conceptual designs. The contractor In Task 111, for providing escape capability for the crew of Trade Studies, shall prepare performance space vehicles have been studied in signjficant simulation models of the conceptual designs detail since before the first United States using the EASY5fEASIEST Computer Program (U.S.) Manned Space Program, Project Mercury. (Reference 3) software with the escape system The reason for the numerous space escape study coniponent and analysis input files appropriately efforts in the 1960's and 1970's are obvious; modified for conf igurations of iriterest to practically all aspects of manned space flight conduct an in-depth trade study of the candidate were unknown. The United States was "in a hurry" concepts. to establish space superiority. And, of course, all space flights were done in view of the entire world. The greatest concern for crew INTRODUCTION The aerospace vehicles of the safety in the early space projects was the future will incorporate hypervelocity on-the-pad or launch phase of the mission. The technologies, providing the capability of flying Mercury and Apollo escape systems were for the at much higher altitudes and much faster speeds on-the-pad and early boost phases only (the than the current' niilitary aircraft. These powered escape towers were jettisoned vehicles wfll have the cepability to be in orbit shortly after launch). Gemini employed ejection from one to three revolutions around the earth. seats for the crew, therefore It had a post 54 1 * c-7 The lower value corresponds to a vehicle typical of the NASA design yielding an entry trajectory that has a higher angle of attack, higher altitude approach, minimuc! heating, and minimum aerodyrbamic loading. The higher value represents a vehicle with a maximum Lift-to-Drag ratio (L/D) providing ar entry path yielding greater range or crossrange flight capability which is more characteristjc of desired military performance in the KVT class vehicles. The vehicles allow for a payload approximately equal to 1% of the total takeoff weight which is estimate6 to be 1.3 to 1.6 million pounds. The Air Force SOW Task 1 requires the contractor to postulate escape systers concepts to provide for survivable escape and recovery throughout the phases of flight allowed by the selected VLV or HLV performance envelopes; 1.e. 1) 1.aunch. 2) upper atmospheric hypervelocity flight, 3) orbit, 4) atmospheric entry, 5) terminal epproach, and 6) landing. Initially the contractor is to develop basic escape system concepts which proTiide for crew escape from initjal conditioris wi.thin the selected vehicle's flight performance envelope that result in final crew landing within the continental United States (CONUS) from orbital flight, or anywhere on earth for all other flight conditions. Subsequently, the contractor shall separately consider advanced escape system concepts for each of the selected vehicles. These advanced escape system concepts shall possess sufficient performance capabiljties to: 1) allow for recovery within the CCMUS for escape initiated from orbit, 2) a1l.o~ for extended cross range fl.ight for escape initiated during upper atmospheric hypervelocity flight, and 3) allow for immediate recovery anywhere on earth for all other escape conditions. Within these reqairements the desired goal of achieving escape system concepts exhibiting minimum weight end minimum volume shall be sought. During Task 11 the contractor is required to investigate promising technologies in the fields of aerodynamics, thermodynamic protection, propulsion, materials, structures, flight controls, 1.ife support and human protection that. are necessary to i.mplement the various concepts with maximum escape performance and minimal weight penalty to the overall vehicle performacce. The identification of alternative technologies for Implementing each fundmental functional requirement as w~ll as the prel.iminary sizing designs of each alternative technology is required. SOW Task I11 involves a comparative trade study of the concepts defined in Task I and their associated technologies investigated in Task I1 to select the best alternative technolopy to implement each fundmental functional requirement identified in Task I. Volume, cost, weight, risk, compatibility with the gross concept and I development requirements are to be used as t.rade criteria with suitable merit welghts selected hy the contractor. The contractor shall e