TY - CHAP A1 - Lao, B. A1 - Bührig-Polaczek, A. A1 - Röth, Thilo ED - Wielage, Bernhard T1 - Funktionsintegrierte Leichtbaustrukturen in gussintensiver Metall-Hybridbauweise T2 - Verbundwerkstoffe und Werkstoffverbunde: Tagungsband zum 18. Symposium ; 30.03.2011 bis 01.04.2011, Chemnitz Y1 - 2011 SN - 978-3-00-033801-4 N1 - Schriftenreihe Werkstoffe und werkstofftechnische Anwendungen ; 41 SP - 413 EP - 421 PB - Eigenverlag CY - Chemnitz ER - TY - CHAP A1 - Dachwald, Bernd A1 - Xu, Changsheng A1 - Feldmann, Marco A1 - Plescher, Engelbert T1 - IceMole : Development of a novel subsurface ice probe and testing of the first prototype on the Morteratsch Glacier T2 - EGU General Assembly 2011 Vienna | Austria | 03 – 08 April 2011 N2 - We present the novel concept of a combined drilling and melting probe for subsurface ice research. This probe, named “IceMole”, is currently developed, built, and tested at the FH Aachen University of Applied Sciences’ Astronautical Laboratory. Here, we describe its first prototype design and report the results of its field tests on the Swiss Morteratsch glacier. Although the IceMole design is currently adapted to terrestrial glaciers and ice shields, it may later be modified for the subsurface in-situ investigation of extraterrestrial ice, e.g., on Mars, Europa, and Enceladus. If life exists on those bodies, it may be present in the ice (as life can also be found in the deep ice of Earth). Y1 - 2011 ER - TY - CHAP A1 - Thenent, N. E. A1 - Dahmann, Peter T1 - Increasing aircraft design flexibility ‐ The development of a hydrostatic transmission for gliders with self‐launching capability T2 - Deutscher Luft- und Raumfahrtkongress 2011 : Bremen, 27. bis 29. September 2011 ; Tagungsband Y1 - 2011 SN - 978-3-9321-8274-7 SP - 865 EP - 883 PB - Dt. Gesellschaft für Luft- und Raumfahrt CY - Bonn ER - TY - CHAP A1 - Thenent, N. E. A1 - Dahmann, Peter T1 - Hydrostatic propeller drive T2 - Proceedings of the conference : 18 - 20 May, 2011 Tampere, Finland / the Twelth Scandinavian International Conference on Fluid Power, SICFP'11. Ed.: Harri Sairiala ... Vol. 1 Y1 - 2011 SN - 978-952-15-2517-9 SP - 217 EP - 227 CY - Tampere ER - TY - CHAP A1 - Dahmann, Peter T1 - Stemme S10 VTX als multifunktionales Forschungsflugzeug T2 - Deutscher Luft- und Raumfahrtkongress 2011 : Bremen, 27. bis 29. September 2011 ; Tagungsband Y1 - 2011 SN - 978-3-9321-8274-7 SP - 357 EP - 364 PB - Dt. Gesellschaft für Luft- und Raumfahrt CY - Bonn ER - TY - CHAP A1 - Havermann, Marc A1 - Seiler, F. A1 - Henning, P. ED - Dillmann, Andreas ED - Heller, Gerd ED - Klaas, Michael ED - Kreplin, Hans-Peter ED - Nitsche, Wolfgang ED - Schröder, Wolfgang T1 - Shock Tunnel Experiments and CFD Simulation of Lateral Jet Interaction in Hypersonic Flows T2 - New Results in Numerical and Experimental Fluid Mechanics VII; Contributions to the 16th STAB/DGLR Symposium Aachen, Germany 2008 Y1 - 2010 SN - 9783642142437 U6 - https://doi.org/10.1007/978-3-642-14243-7_45 N1 - Notes on numerical fluid mechanics and multidisciplinary design 112 SP - 365 EP - 372 PB - Springer CY - Berlin ER - TY - CHAP A1 - Borggräfe, Andreas A1 - Dachwald, Bernd T1 - Mission performance evaluation for solar sails using a refined SRP force model with variable optical coefficients T2 - 2nd International Symposium on Solar Sailing N2 - Solar sails provide ignificant advantages over other low-thrust propulsion systems because they produce thrust by the momentum exchange from solar radiation pressure (SRP) and thus do not consume any propellant.The force exerted on a very thin sail foil basically depends on the light incidence angle. Several analytical SRP force models that describe the SRP force acting on the sail have been established since the 1970s. All the widely used models use constant optical force coefficients of the reflecting sail material. In 2006,MENGALI et al. proposed a refined SRP force model that takes into account the dependancy of the force coefficients on the light incident angle,the sail’s distance from the sun (and thus the sail emperature) and the surface roughness of the sail material [1]. In this paper, the refined SRP force model is compared to the previous ones in order to identify the potential impact of the new model on the predicted capabilities of solar sails in performing low-cost interplanetary space missions. All force models have been implemented within InTrance, a global low-thrust trajectory optimization software utilizing evolutionary neurocontrol [2]. Two interplanetary rendezvous missions, to Mercury and the near-Earth asteroid 1996FG3, are investigated. Two solar sail performances in terms of characteristic acceleration are examined for both scenarios, 0.2 mm/s2 and 0.5 mm/s2, termed “low” and “medium” sail performance. In case of the refined SRP model, three different values of surface roughness are chosen, h = 0 nm, 10 nm and 25 nm. The results show that the refined SRP force model yields shorter transfer times than the standard model. Y1 - 2010 N1 - 2nd International Symposium on Solar Sailing, ISSS 2010, 2010-07-20 - 2010-07-22. New York City College of Technology of the City University of New York, USA SP - 1 EP - 6 ER - TY - CHAP A1 - Kapoor, Hrshi A1 - Boller, Christian A1 - Giljohann, Sebastian A1 - Braun, Carsten T1 - Strategies for structural health monitoring implementation potential assessment in aircraft operational life extension considerations T2 - 2nd International Symposium on NDT in Aerospace : November 22-24, 2010 Hamburg, Germany Y1 - 2010 SN - 978-3-940283-28-3 PB - Dt. Gesellschaft für Zerstörungsfreie Prüfung CY - Berlin ER - TY - CHAP A1 - Pasligh, N. A1 - Funke, D. A1 - Röth, Thilo A1 - Krack, R. T1 - Leichtbau Quertrager als Stahlblech-Aluminiumdruckguss-Hybrid - Von der numerischen Berechnung bis zum realen Prototypen T2 - VDI BERICHTE Y1 - 2010 SN - 978-3-18-092107-5 N1 - 15. Kongress SIMVEC Berechnung und Simulation im Fahrzeugbau, Baden-Baden, 16. und 17. November 2010 PB - VDI Verlag CY - Düsseldorf ER - TY - CHAP A1 - Kapoor, Hrshi A1 - Braun, Carsten A1 - Boller, Christian ED - Casciati, Fabio T1 - Modelling and optimisation of maintenance intervals to realize structural health monitoring applications on aircraft T2 - Structural health monitoring 2010 : proceedings of the Fifth European Workshop on Structural Health Monitoring held at Sorrento, Naples, Italy, June 28 - July 4, 2010 ; [EWSHM] Y1 - 2010 SN - 978-1-60595-024-2 SP - 55 EP - 63 PB - DEStech Publ. CY - Lancaster, Pa. ER - TY - CHAP A1 - Börner, Sebastian A1 - Funke, Harald A1 - Hendrick, P. A1 - Recker, E. T1 - LES of Jets In Cross-Flow and Application to the “Micromix” Hydrogen Combustion T2 - XIX International Symposium on Air Breathing Engines 2009 (ISABE 2009) : Proceedings of a meeting held 7-11 September 2009, Montreal, Canada Y1 - 2009 SN - 9781615676064 SP - 1555 EP - 1561 ER - TY - CHAP A1 - Kowalski, Julia A1 - Bugnion, Louis T1 - An extended shallow flow theory for natural debris flows Y1 - 2009 N1 - 2009 Portland GSA Annual Meeting (18-21 October 2009); Geological Society of America VL - 41 IS - 7 SP - 609 EP - 609 ER - TY - CHAP A1 - Röth, Thilo A1 - Stark, R. T1 - Die Rolle der virtuellen Produktentstehung bei der Integration von Karosseriesystemen T2 - Karosseriekongress Systemintegration in der Karosserietechnik : 17. und 18. März 2009 in Baden-Baden / Kongressleitung: Reiner Stark Y1 - 2009 SN - 978-3-9812624-4-5 N1 - Karosseriekongress ; (2009.03.17-18 : ; Baden-Baden) PB - VDI-Wissensforum CY - Düsseldorf ER - TY - CHAP A1 - Dachwald, Bernd A1 - Ohndorf, Andreas A1 - Spurmann, J. A1 - Loeb, H. W. A1 - Schartner, Karl-Heinz A1 - Seboldt, Wolfgang T1 - Mission design for a SEP mission to saturn T2 - 60th International Astronautical Congress 2009 (IAC 2009) N2 - Within ESA's Cosmic Vision 2015-2025 plan, a mission to explore the Saturnian System, with special emphasis on its two moons Titan and Enceladus, was selected for study, termed TANDEM (Titan and Enceladus Mission). In this paper, we describe an optimized mission design for a TANDEM-derived solar electric propulsion (SEP) mission. We have chosen the SEP mission scenario for the interplanetary transfer of the TANDEM spacecraft because all feasible gravity assist sequences for a chemical transfer between 2015 and 2025 result in long flight times of about nine years. Our SEP system is based on the German RIT ion engine. For our optimized mission design, we have extensively explored the SEP parameter space (specific impulse, thrust level, power level) and have calculated an optimal interplanetary trajectory for each setting. In contrast to the original TANDEM mission concept, which intends to use two launch vehicles and an all-chemical transfer, our SEP mission design requires only a single Ariane 5 ECA launch for the same payload mass. Without gravity assist, it yields a faster and more flexible transfer with a fight time of less than seven years, and an increased payload ratio. Our mission design proves thereby the capability of SEP even for missions into the outer solar system. Y1 - 2009 SN - 978-1-61567-908-9 N1 - 12-16 October 2009, Daejeon, Republic of Korea. PB - Curran Associates, Inc. CY - Red Hook, NY ER - TY - CHAP A1 - Dachwald, Bernd A1 - Wurm, P. T1 - Design concept and modeling of an advanced solar photon thruster T2 - Advances in the Astronautical Sciences N2 - The so-called "compound solar sail", also known as "Solar Photon Thruster" (SPT), holds the potential of providing significant performance advantages over the flat solar sail. Previous SPT design concepts, however, do not consider shadowing effects and multiple reflections of highly concentrated solar radiation that would inevitably destroy the gossamer sail film. In this paper, we propose a novel advanced SPT (ASPT) design concept that does not suffer from these oversimplifications. We present the equations that describe the thrust force acting on such a sail system and compare its performance with respect to the conventional flat solar sail. KW - solar sails Y1 - 2009 SN - 978-087703554-1 SN - 00653438 N1 - 19th AAS/AIAA Space Flight Mechanics Meeting; Savannah, GA; United States; 8 February 2009 through 12 February 2009 SP - 723 EP - 740 PB - American Astronautical Society CY - San Diego, Calif. ER - TY - CHAP A1 - Spurmann, Jörn A1 - Ohndorf, Andreas A1 - Dachwald, Bernd A1 - Seboldt, Wolfgang A1 - Löb, Horst A1 - Schartner, Karl-Heinz T1 - Interplanetary trajectory optimization for a sep mission to Saturn T2 - 60th International Astronautical Congress 2009 N2 - The recently proposed NASA and ESA missions to Saturn and Jupiter pose difficult tasks to mission designers because chemical propulsion scenarios are not capable of transferring heavy spacecraft into the outer solar system without the use of gravity assists. Thus our developed mission scenario based on the joint NASA/ESA Titan Saturn System Mission baselines solar electric propulsion to improve mission flexibility and transfer time. For the calculation of near-globally optimal low-thrust trajectories, we have used a method called Evolutionary Neurocontrol, which is implemented in the low-thrust trajectory optimization software InTrance. The studied solar electric propulsion scenario covers trajectory optimization of the interplanetary transfer including variations of the spacecraft's thrust level, the thrust unit's specific impulse and the solar power generator power level. Additionally developed software extensions enabled trajectory optimization with launcher-provided hyperbolic excess energy, a complex solar power generator model and a variable specific impulse ion engine model. For the investigated mission scenario, Evolutionary Neurocontrol yields good optimization results, which also hold valid for the more elaborate spacecraft models. Compared to Cassini/Huygens, the best found solutions have faster transfer times and a higher mission flexibility in general. KW - Spacecraft KW - Reusable Rocket Engines KW - Hybrid Propellants Y1 - 2009 SN - 9781615679089 N1 - 60th International Astronautical Congress 2009 (IAC 2009) Held 12-16 October 2009, Daejeon, Republic of Korea. SP - 5234 EP - 5248 ER - TY - CHAP A1 - Dachwald, Bernd A1 - Wurm, P. T1 - Mission analysis for an advanced solar photon thruster T2 - 60th International Astronautical Congress 2009, IAC 2009 N2 - The so-called "compound solar sail", also known as "Solar Photon Thruster" (SPT), is a solar sail design concept, for which the two basic functions of the solar sail, namely light collection and thrust direction, are uncoupled. In this paper, we introduce a novel SPT concept, termed the Advanced Solar Photon Thruster (ASPT). This model does not suffer from the simplified assumptions that have been made for the analysis of compound solar sails in previous studies. We present the equations that describe the force, which acts on the ASPT. After a detailed design analysis, the performance of the ASPT with respect to the conventional flat solar sail (FSS) is investigated for three interplanetary mission scenarios: An Earth-Venus rendezvous, where the solar sail has to spiral towards the Sun, an Earth-Mars rendezvous, where the solar sail has to spiral away from the Sun, and an Earth-NEA rendezvous (to near-Earth asteroid 1996FG3), where a large orbital eccentricity change is required. The investigated solar sails have realistic near-term characteristic accelerations between 0.1 and 0.2mm/s2. Our results show that a SPT is not superior to the flat solar sail unless very idealistic assumptions are made. KW - Interplanetary flight Y1 - 2009 SN - 978-161567908-9 N1 - 60th International Astronautical Congress 2009, IAC 2009; Daejeon; South Korea; 12 October 2009 through 16 October 2009 VL - 8 SP - 6838 EP - 6851 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Schartner, Karl-Heinz A1 - Loeb, H. W. A1 - Dachwald, Bernd A1 - Ohndorf, Andreas T1 - Perspectives of electric propulsion for outer planetary and deep space missions T2 - European Planetary Science Congress 2009 N2 - Solar-electric propulsion (SEP) is superior with respect to payload capacity, flight time and flexible launch window to the conventional interplanetary transfer method using chemical propulsion combined with gravity assists. This fact results from the large exhaust velocities of electric low–thrust propulsion and is favourable also for missions to the giant planets, Kuiper-belt objects and even for a heliopause probe (IHP) as shown in three studies by the authors funded by DLR. They dealt with a lander for Europa and a sample return mission from a mainbelt asteroid [1], with the TANDEM mission [2]; the third recent one investigates electric propulsion for the transfer to the edge of the solar system. All studies are based on triple-junction solar arrays, on rf-ion thrusters of the qualified RIT-22 type and they use the intelligent trajectory optimization program InTrance [3]. Y1 - 2009 N1 - European Planetary Science Congress 2009, 13-18 September, Potsdam, Germany SP - 416 EP - 416 ER - TY - CHAP A1 - Gehler, M. A1 - Ober-Blöbaum, S. A1 - Dachwald, Bernd T1 - Application of discrete mechanics and optimal control to spacecraft in non-keplerian motion around small solar system bodies T2 - Procceedings of the 60th International Astronautical Congress N2 - Prolonged operations close to small solar system bodies require a sophisticated control logic to minimize propellant mass and maximize operational efficiency. A control logic based on Discrete Mechanics and Optimal Control (DMOC) is proposed and applied to both conventionally propelled and solar sail spacecraft operating at an arbitrarily shaped asteroid in the class of Itokawa. As an example, stand-off inertial hovering is considered, recently identified as a challenging part of the Marco Polo mission. The approach is easily extended to stand-off orbits. We show that DMOC is applicable to spacecraft control at small objects, in particular with regard to the fact that the changes in gravity are exploited by the algorithm to optimally control the spacecraft position. Furthermore, we provide some remarks on promising developments. KW - Spacecraft Y1 - 2009 SN - 978-161567908-9 N1 - 60th International Astronautical Congress 2009, IAC 2009; Daejeon; South Korea; 12 October 2009 through 16 October 2009 SP - 1360 EP - 1371 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Funke, Harald A1 - Esch, Thomas A1 - Roosen, Peter ED - Bartz, Wilfried J. T1 - Using motor gasoline for aircrafts - coping with growing bio-fuel-caused risks by understanding cause-effect relationship T2 - Fuels 2009 : mineral oil based and alternative fuels ; 7th international colloquium ; January 14 - 15, 2009 N2 - The utilisation of vehicle-oriented gasoline in general aviation is very desirable for both ecological and economical reasons, as well as for general considerations of availability. As of today vehicle fuels may be used if the respective engine and cell are certified for such an operation. For older planes a supplementary technical certificate is provided for gasoline mixtures with less than 1 % v/v ethanol only, though. Larger admixtures of ethanol may lead to sudden engine malfunction and should be considered as considerable security risks. Major problems are caused by the partially ethanol non-withstanding materials, a necessarily changed stochiometric adjustment of the engine for varying ethanol shares and the tendency for phase separation in the presence of absorbed water. The concepts of the flexible fuel vehicles are only partially applicable in the view of air security. Y1 - 2009 SN - 978-3-924813-75-8 SP - 237 EP - 244 PB - Technische Akademie Esslingen (TAE) CY - Ostfildern ER -