Thermostructural concepts for hypervelocity vehicles

In the design of hypervelocity veh~cles (HVV). a key driving parameter is the structural mass fraction of the system. The mass fraction greatly influences the performance and payload capabilities of the vehicle. For example. a reduction of one pound of structural weight would effectively translate into an additional pound of payload, or alternatively, approximately ten fewer pounds of propellant. Through the optimization of thermostructural concepts. a significant increase in overall mission perfbrmance can be reallred. Such an optimiration requires not only good familiarity with the available material optlons and therrnostructural concepts. but also a thorough knowledge of the thermal. inertial, aerodynamic, and control loads on the vehicle as a consequence of hqpervelocity flight conditions. This optimiration process the establishment o l aeroheating and other critical loads, the consideration of material alternatives, and the formulation of thermostructural concep t wa the primary l'i~cus ol' t h ~ \ study. A suborbital vehicle (Figure I ) and the aswciated trajectory (Figure 2 ) a i described in Rckrence I were chosen as stud) baselines. These selections wcrc Idlowed b> a series of interrclated design and anal] tical tazks. during which a number of thcri~~ostructural trade \tudie\ \\el-c conducted. The primary results ol'the stud! include detailed w i g h t estlmates h r the candidate thernio~tructural concepts and the selecSUB-ORBITER SYNERGETIC PLANE CHANGE