Tobias Schwanekamp

System Studies on Active Thermal Protection of a Hypersonic Suborbital Passenger Transport Vehicle

Aerodynamic heating is a critical design aspect for the development of reusable hypersonic transport and reentry vehicles. The reliability in terms of thermal resistance is one of the major driving factors with respect to the design margins, the mass balance and finally the total costs of a configuration. Potential designs of active cooling systems for critical regions such as the vehicle nose and leading edges are presented as well as preliminary approaches for their impact on the total mass. The visionary suborbital passenger transport concept SpaceLiner is taken as a reference vehicle for these studies. Covering the whole flight regime from subsonic to Mach numbers of more than 20, this vehicle creates high demands on the thermal protection system. Part of the work was performed within the DLR research project THERMAS.

Preliminary Multidisciplinary Design Studies on an Upgraded 100 Passenger SpaceLiner Derivative

The visionary ultrafast passenger transportation concept SpaceLiner has been proposed by the Space Launcher System Analysis Department of the German Aerospace Center DLR. Based on rocket propulsion the baseline configuration of the two stage RLV should be capable of carrying about 50 passengers along the ambitious westbound route from Australia to Europe within 90 minutes. Based on the most recent and mature SpaceLiner configuration and its mission data, an upgraded 100 passenger derivative is explored since an increase of efficiency is expected and potential promising alternative travel routes and the correspondent system requirements are investigated. Preliminary estimation engineering tools are utilized within the initial, iterative design process, in order to identify potential configurations. The configuration approach most consistent with the predefined system and mission requirements is presented.

Technical Maturation of the SpaceLiner Concept

DLR’s launcher systems analysis division is investigating since a couple of years a visionary, extremely fast passenger transportation concept reaching the edges of space based on rocket propulsion. Work is now focusing on the iterative sizing of all major subcomponents in nominal and off-nominal flight conditions. The paper describes the recent technical progress achieved in the SpaceLiner 7 configuration supported by the EU-funded studies FAST20XX (Future high-Altitude high-Speed Transport 20XX) and CHATT (Cryogenic Hypersonic Advanced Tank Technologies). The focus of the paper is on all system aspects of the reference vehicle’s preliminary design including its nominal trajectory and first assessment of its environmental impact.

Aero-thermo-dynamic analysis of the Spaceliner-7.1 vehicle in high altitude flight

SpaceLiner, designed by DLR, is a visionary, extremely fast passenger transportation concept. It consists of two stages: a winged booster, a vehicle. After separation of the two stages, the booster makes a controlled re-entry and returns to the launch site. According to the current project, version 7-1 of SpaceLiner (SpaceLiner-7.1), the vehicle should be brought at an altitude of 75 km and then released, undertaking the descent path. In the perspective that the vehicle of SpaceLiner-7.1 could be brought to altitudes higher than 75 km, e.g. 100 km or above and also for a speculative purpose, in this paper the aerodynamic parameters of the SpaceLiner-7.1 vehicle are calculated in the whole transition regime, from continuum low density to free molecular flows. Computer simulations have been carried out by three codes: two DSMC codes, DS3V in the altitude interval 100-250 km for the evaluation of the global aerodynamic coefficients and DS2V at the altitude of 60 km for the evaluation of the heat flux and pre...

Cryogenic Propellant Tank and Feedline Design Studies in the Framework of the CHATT Project

The EU-funded project CHATT (Cryogenic Hypersonic Advanced Tank Technologies) has been initiated early 2012 and is part of the European Commission’s Seventh Framework Programme (FP7). CHATT focuses on the development of novel cryogenic tank and propellant supply technologies. One of the tasks within the project is the investigation of adequate propellant crossfeed systems. Propellant crossfeed principally allows large mass savings for parallel burn vehicles such as the visionary passenger transport concept “SpaceLiner” which has been proposed by the Space Launcher Systems Analysis Department of the German Aerospace Center DLR. Therefore the tank and feedline systems of the SpaceLiner concept are studied by means of reference data and the results of simulations conducted with in-house and commercial tools.

SpaceLiner Technical Progress and Mission Definition

DLR’s launcher systems analysis division is investigating since a couple of years a visionary, extremely fast passenger transportation concept reaching the edges of space based on rocket propulsion. Thanks to multi-national collaboration, the technical lay-out of the SpaceLiner has now matured to Phase A conceptual design level. Iterative sizing of all major subcomponents in nominal and off-nominal flight conditions has been performed. The paper describes the recent technical progress achieved in the SpaceLiner 7 configuration, • mainly system aspects of the reference vehicle’s preliminary design including establishment of a preliminary structural concept, • main propulsion system definition, • pre-development of a passenger cabin and rescue capsule and its specific challenges, • preliminary sizing of the thermal protection and active cooling systems, • mission definition with its nominal trajectories including potential ground infrastructure, • programmatic development aspects

Rarefied Aerothermodynamics Technology Development for Future High-Altitude High-Speed Transport (EU-FAST20XX)

First subject of the present paper has been the experimental and numerical characterization of test chamber flow of DLR-V2G low-density wind tunnel, in the frame of EU-FP7 FAST20XX project activities dedicated to the validation of numerical tools able to predict rarefaction effects in suborbital flight. Pitot pressure radial profiles measured at different positions downstream the test chamber have been compared at nozzle exit to numerical results obtained with different methodologies accounting for rarefaction effects (CFD with slip-flow boundary conditions, a hybrid CFD-DSMC procedure), and a re-definition of the V2G facility envelope in terms of flight-relevant parameters (Mach, Reynolds, Knudsen numbers) has been presented. A good agreement between experiments and numerical results has been achieved for M=12 and M=16 cases (not as good for M=22), thus confirming that the test chamber flow knowledge is of fundamental importance for a proper numerical rebuilding of an experimental test campaign. Further, the aerodynamic coefficients of lift, drag and pitching moment of the analyzed lifting body configuration have been experimentally determined by means of three component force and moment measurements in V2G and the influence of rarefaction onto the aerodynamic coefficients have been shown. The results have numerically been validated by means of DSMC calculations. After the validation of the numerical tools, the high altitude effects to the future hypersonic/suborbital re-entry vehicle SpaceLiner have been analyzed. Bridging functions have been developed and validated by means of DSMC calculations. The effects of rarefaction on global longitudinal aerodynamics of SpaceLiner in the range of altitude 65÷85 km have been pointed out by comparing to the aerodatabase in continuum regime conditions. DSMC computation has been done in the higher SpaceLiner altitude point confirming the bridging function results and providing heat transfer estimations. Two versions of SpaceLiner have been analyzed: SL4.3 and SL7.1.

Trim requirements and impact on wing design for the high-speed passenger transport concept SpaceLiner

An interdisciplinary study on the SpaceLiner orbiter is conducted focusing on the aspect of trimming and its impact on aerodynamical performance and structural design of the wing. Part of this study is to update the previously optimized aerodynamic shape taking into account the aspect of trim capability while maximizing the aerodynamic efficiency. This highly automated process results in a new preliminary definition of the aerodynamic shape of the SpaceLiner orbiter. A dimensioning abort case trajectory is defined following the recent update of the nominal return trajectory. Both serve as a starting point to the investigation of the trim requirement. The study confirms that the updated aerodynamic shape requires only small flap deflection angles for trimming, even under degraded conditions, and thus limits the impact on the lift-to-drag ratio. A structural analysis on the wing attests the importance of limiting the dimensioning flap deflection angles as the forces exercised by the flaps on the hinges can be considerable.