Multidisciplinary Analysis of a Lifting Body Launch Vehicle

Abstract

As part of phase 2 of the X-33 Program, NASA selected an integrated lifting body/aerospike engine con guration as the study vehicle for the conceptual analysis of a single-stage-to-orbit reusable launch vehicle. A team at NASA Langley Research Center participated in the screening and evaluation of a number of proposed vehicle con gurations in the early phases of the conceptual design process. The performance analyses that supported these studies were conducted to assess the effect of the vehicle's lifting capability, linear aerospike engine, and metallic thermal protection system on the weight and performance of the vehicle. These performance studies were conducted in a multidisciplinary fashion that indirectly linked the trajectory optimization with weight estimation and aerothermal analysis tools. This approach was necessary to develop optimized ascent and entry trajectories that met all vehicle design constraints. Signi cant improvements in ascent performance were achieved when the vehicle ew a lifting trajectory and varied the engine mixture ratio during ight. Also, a considerable reduction in empty weight was possible by adjusting the total oxidizer-to-fuel and liftoff thrust-to-weight ratios. However, the optimal ascent ight pro le had to be altered to ensure that the vehicle could be trimmed in pitch using only the ow diverting capability of the aerospike engine. Likewise, the optimal entry trajectory had to be tailored to meet thermal protection system heating rate and transition constraints while satisfying a crossrange requirement. NomenclatureC L = lift coef cient I sp = speci c impulse, s M e = edge Mach number M 1 = freestream Mach number O=F = total oxidizer-to-fuel ratio q = dynamic pressure, psf q ¢ ® = dynamic pressure times angle-of-attack,psf ¢ deg Re µ = momentum thickness Reynolds number S = aerodynamic reference area, ft 2 T =W = thrust-to-weightratio .T =W / eng = engine thrust-to-weightratio W = entry weight, lb W empty = empty weight, lb W ins = inserted weight, lb X=L = body position over vehicle length ® = angle of attack, deg 1 payload = change in payload from

Displacements of Metallic Thermal Protection System Panels During Reentry

“…The trajectory for this vehicle had been carefully tailored to delay the onset of transition. 6 The main concern is for premature boundary layer transition during the extreme heating portions of the flight (up to 1500 s), where boundary layer transition could results in significant augmentation of the already high heating rates, resulting in TPS exceeding its temperature limits, and having a significantly higher integrated heat load. The resulting temperature differences across the honeycomb panel thickness at the three axial stations of 6.1, 20.4 and 30.4 m are shown in Fig.…”

“…2 where the vehicle reentry altitude, velocity, and Mach number histories are shown. 6 This is a 2570 s long reentry, with reentry velocity of 7.63 km/s at an altitude of 122 km. The flow is hypersonic until 1970 s into reentry.…”

Design Exploration of Aerodynamic Wing Shape for Reusable Launch Vehicle Flyback Booster

“…Single-stage-to-orbit (SSTO) launch systems, such as the X-33 (see Ref. 3), have been studied because this configuration is ideal for reuse similar to that of aircraft. However, these studies indicated that the SSTO configuration had difficulties because it would require a higher performance propulsion system and greater reduction of its structure weight than can be attained based on the present technology.…”

Multi-level of Fidelity Multi-Disciplinary Design Optimization of Small, Solid-Propellant Launch Vehicles

“…Progress in automation of multi-disciplinary design and analysis process has been getting faster in recent years using various analysis tools. [1][2][3][4][5][6][7][8] The two main challenges of Multi-Disciplinary Design Optimization (MDO) are computational expense and organizational complexity. In this regard, mathematical modeling and formulation of the design problem play the main role.…”