TY - CHAP A1 - Dachwald, Bernd A1 - Boehnhardt, Herrmann A1 - Broj, Ulrich A1 - Geppert, Ulrich R. M. E. A1 - Grundmann, Jan-Thimo A1 - Seboldt, Wolfgang A1 - Seefeldt, Patric A1 - Spietz, Peter A1 - Johnson, Les A1 - Kührt, Ekkehard A1 - Mottola, Stefano A1 - Macdonald, Malcolm A1 - McInnes, Colin R. A1 - Vasile, Massimiliano A1 - Reinhard, Ruedeger T1 - Gossamer roadmap technology reference study for a multiple NEO Rendezvous Mission T2 - Advances in solar sailing N2 - A technology reference study for a multiple near-Earth object (NEO) rendezvous mission with solar sailcraft is currently carried out by the authors of this paper. The investigated mission builds on previous concepts, but adopts a strong micro-spacecraft philosophy based on the DLR/ESA Gossamer technology. The main scientific objective of the mission is to explore the diversity of NEOs. After direct interplanetary insertion, the solar sailcraft should—within less than 10 years—rendezvous three NEOs that are not only scientifically interesting, but also from the point of human spaceight and planetary defense. In this paper, the objectives of the study are outlined and a preliminary potential mission profile is presented. Y1 - 2014 SN - 978-3-642-34906-5 (Print) ; 978-3-642-34907-2 (E-Book) SP - 211 EP - 226 PB - Springer CY - Berlin [u.a.] ER - TY - CHAP A1 - Dachwald, Bernd T1 - Global optimization of low-thrust space missions using evolutionary neurocontrol T2 - Proceedings of the international workshop on global optimization N2 - Low-thrust space propulsion systems enable flexible high-energy deep space missions, but the design and optimization of the interplanetary transfer trajectory is usually difficult. It involves much experience and expert knowledge because the convergence behavior of traditional local trajectory optimization methods depends strongly on an adequate initial guess. Within this extended abstract, evolutionary neurocontrol, a method that fuses artificial neural networks and evolutionary algorithms, is proposed as a smart global method for low-thrust trajectory optimization. It does not require an initial guess. The implementation of evolutionary neurocontrol is detailed and its performance is shown for an exemplary mission. KW - Evolutionary Neurocontrol KW - Spacecraft Trajectory Optimization KW - Low-Thrust Propulsion Y1 - 2005 SP - 85 EP - 90 ER - TY - CHAP A1 - Dachwald, Bernd A1 - Ohndorf, Andreas T1 - Global optimization of continuous-thrust trajectories using evolutionary neurocontrol T2 - Modeling and Optimization in Space Engineering N2 - Searching optimal continuous-thrust trajectories is usually a difficult and time-consuming task. The solution quality of traditional optimal-control methods depends strongly on an adequate initial guess because the solution is typically close to the initial guess, which may be far from the (unknown) global optimum. Evolutionary neurocontrol attacks continuous-thrust optimization problems from the perspective of artificial intelligence and machine learning, combining artificial neural networks and evolutionary algorithms. This chapter describes the method and shows some example results for single- and multi-phase continuous-thrust trajectory optimization problems to assess its performance. Evolutionary neurocontrol can explore the trajectory search space more exhaustively than a human expert can do with traditional optimal-control methods. Especially for difficult problems, it usually finds solutions that are closer to the global optimum. Another fundamental advantage is that continuous-thrust trajectories can be optimized without an initial guess and without expert supervision. Y1 - 2019 SN - 978-3-030-10501-3 SN - 978-3-030-10500-6 U6 - http://dx.doi.org/10.1007/978-3-030-10501-3_2 N1 - Springer Optimization and Its Applications, vol 144 gedruckt unter der Signatur 21 ZSS 46 in der Bereichsbibliothek Eupener Str. vorhanden SP - 33 EP - 57 PB - Springer CY - Cham ER - TY - JOUR A1 - Dachwald, Bernd A1 - Turyshev, Slava G. A1 - Dittus, H. A1 - Shao, M. [u.a.] T1 - Fundamental Physics with the Laser Astrometric Test Of Relativity / S.G. Turyshev ; H. Dittus ; M. Shao ... B.Dachwald ... JF - Proceedings of the 39th ESLAB Symposium "Trends in Space Science and Cosmic Vision 2020" : 19 - 21 April 2005, ESTEC, Noordwijk, the Netherlands / European Space Agency. [Comp. by: F. Favata ...] . - (ESA SP ; 588) Y1 - 2005 SN - 9290928999 N1 - ISBN der CD-ROM-Ausg.: 9290928999 ; Symposium Trends in Space Science and Cosmic Vision 2020 <2005, Noordwijk> ; ESLAB symposium <39, 2005, Noordwijk> ; European Space Laboratory SP - 8 EP - 11 PB - ESA Publ. Div. CY - Noordwijk ER - TY - CHAP A1 - Grundmann, Jan Thimo A1 - Bauer, Waldemar A1 - Biele, Jens A1 - Cordero, Frederico A1 - Dachwald, Bernd A1 - Koncz, Alexander A1 - Krause, Christian A1 - Mikschl, Tobias A1 - Montenegro, Sergio A1 - Quantius, Dominik A1 - Ruffer, Michael A1 - Sasaki, Kaname A1 - Schmitz, Nicole A1 - Seefeldt, Patric A1 - Tóth, Norbert A1 - Wejmo, Elisabet T1 - From Sail to Soil – Getting Sailcraft Out of the Harbour on a Visit to One of Earth’s Nearest Neighbours T2 - 4th IAA Planetary Denfense Conference - PDC 2015, 13-17 April 2015, Frascati, Roma, Italy Y1 - 2015 ER - TY - CHAP A1 - Grundmann, Jan Thimo A1 - Bauer, Waldemar A1 - Boden, Ralf A1 - Ceriotti, Matteo A1 - Chand, Suditi A1 - Cordero, Federico A1 - Dachwald, Bernd A1 - Dumont, Etienne A1 - Grimm, Christian D. A1 - Heiligers, Jeannette A1 - Herčík, David A1 - Hérique, Alain A1 - Ho, Tra-Mi A1 - Jahnke, Rico A1 - Kofman, Wlodek A1 - Lange, Caroline A1 - Lichtenheldt, Roy A1 - McInnes, Colin A1 - Meß, Jan-Gerd A1 - Mikschl, Tobias A1 - Mikulz, Eugen A1 - Montenegro, Sergio A1 - Moore, Iain A1 - Pelivan, Ivanka A1 - Peloni, Alessandro A1 - Plettemeier, Dirk A1 - Quantius, Dominik A1 - Reershemius, Siebo A1 - Renger, Thomas A1 - Riemann, Johannes A1 - Rogez, Yves A1 - Ruffer, Michael A1 - Sasaki, Kaname A1 - Schmitz, Nicole A1 - Seboldt, Wolfgang A1 - Seefeldt, Patric A1 - Spietz, Peter A1 - Spröwitz, Tom A1 - Sznajder, Maciej A1 - Tóth, Norbert A1 - Vergaaij, Merel A1 - Viavattene, Giulia A1 - Wejmo, Elisabet A1 - Wiedemann, Carsten A1 - Wolff, Friederike A1 - Ziach, Christian T1 - Flights are ten a sail – Re-use and commonality in the design and system engineering of small spacecraft solar sail missions with modular hardware for responsive and adaptive exploration T2 - 70th International Astronautical Congress (IAC) KW - system engineering KW - small solar system body characterisation KW - small spacecraft solar sail KW - small spacecraft asteroid lander KW - responsive space Y1 - 2019 SN - 9781713814856 N1 - 70th International Astronautical Congress (IAC), Washington D.C., United States, 21-25 October 2019 SP - 1 EP - 7 ER - TY - CHAP A1 - Ohndorf, Andreas A1 - Dachwald, Bernd A1 - Seboldt, Wolfgang A1 - Schartner, Karl-Heinz T1 - Flight times to the heliopause using a combination of solar and radioisotope electric propulsion T2 - 32nd International Electric Propulsion Conference N2 - We investigate the interplanetary flight of a low-thrust space probe to the heliopause,located at a distance of about 200 AU from the Sun. Our goal was to reach this distance within the 25 years postulated by ESA for such a mission (which is less ambitious than the 15-year goal set by NASA). Contrary to solar sail concepts and combinations of allistic and electrically propelled flight legs, we have investigated whether the set flight time limit could also be kept with a combination of solar-electric propulsion and a second, RTG-powered upper stage. The used ion engine type was the RIT-22 for the first stage and the RIT-10 for the second stage. Trajectory optimization was carried out with the low-thrust optimization program InTrance, which implements the method of Evolutionary Neurocontrol,using Artificial Neural Networks for spacecraft steering and Evolutionary Algorithms to optimize the Neural Networks’ parameter set. Based on a parameter space study, in which the number of thrust units, the unit’s specific impulse, and the relative size of the solar power generator were varied, we have chosen one configuration as reference. The transfer time of this reference configuration was 29.6 years and the fastest one, which is technically more challenging, still required 28.3 years. As all flight times of this parameter study were longer than 25 years, we further shortened the transfer time by applying a launcher-provided hyperbolic excess energy up to 49 km2/s2. The resulting minimal flight time for the reference configuration was then 27.8 years. The following, more precise optimization to a launch with the European Ariane 5 ECA rocket reduced the transfer time to 27.5 years. This is the fastest mission design of our study that is flexible enough to allow a launch every year. The inclusion of a fly-by at Jupiter finally resulted in a flight time of 23.8 years,which is below the set transfer-time limit. However, compared to the 27.5-year transfer,this mission design has a significantly reduced launch window and mission flexibility if the escape direction is restricted to the heliosphere’s “nose". KW - low-thrust trajectory optimization KW - heliosphere KW - ion propulsion Y1 - 2011 N1 - IEPC-2011-051 32nd International Electric Propulsion Conference,September 11–15, 2011 Wiesbaden, Germany SP - 1 EP - 12 ER - TY - JOUR A1 - Scholz, A. A1 - Ley, Wilfried A1 - Dachwald, Bernd A1 - Miau, J. J. A1 - Juang, J. C. T1 - Flight results of the COMPASS-1 picosatellite mission JF - Acta Astronautica. 67 (2010), H. 9-10 Y1 - 2010 SN - 0094-5765 SP - 1289 EP - 1298 ER - TY - JOUR A1 - Dachwald, Bernd A1 - Schmidt, Tanja D. A1 - Seboldt, Wolfgang A1 - Auweter-Kurtz, T1 - Flight Opportunities from Mars to Earth for Piloted Missions Using Continuous Thrust Propulsion / Schmidt, Tanja D. ; Dachwald, Bernd ; Seboldt, Wolfgang ; Auweter-Kurtz, Monika Y1 - 2003 N1 - 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 20-23 July 2003, Huntsville, Alabama ; AIAA 2003-4573 SP - 1 EP - 9 PB - - ER - TY - JOUR A1 - Baader, Fabian A1 - Boxberg, Marc S. A1 - Chen, Qian A1 - Förstner, Roger A1 - Kowalski, Julia A1 - Dachwald, Bernd T1 - Field-test performance of an ice-melting probe in a terrestrial analogue environment JF - Icarus N2 - Melting probes are a proven tool for the exploration of thick ice layers and clean sampling of subglacial water on Earth. Their compact size and ease of operation also make them a key technology for the future exploration of icy moons in our Solar System, most prominently Europa and Enceladus. For both mission planning and hardware engineering, metrics such as efficiency and expected performance in terms of achievable speed, power requirements, and necessary heating power have to be known. Theoretical studies aim at describing thermal losses on the one hand, while laboratory experiments and field tests allow an empirical investigation of the true performance on the other hand. To investigate the practical value of a performance model for the operational performance in extraterrestrial environments, we first contrast measured data from terrestrial field tests on temperate and polythermal glaciers with results from basic heat loss models and a melt trajectory model. For this purpose, we propose conventions for the determination of two different efficiencies that can be applied to both measured data and models. One definition of efficiency is related to the melting head only, while the other definition considers the melting probe as a whole. We also present methods to combine several sources of heat loss for probes with a circular cross-section, and to translate the geometry of probes with a non-circular cross-section to analyse them in the same way. The models were selected in a way that minimizes the need to make assumptions about unknown parameters of the probe or the ice environment. The results indicate that currently used models do not yet reliably reproduce the performance of a probe under realistic conditions. Melting velocities and efficiencies are constantly overestimated by 15 to 50 % in the models, but qualitatively agree with the field test data. Hence, losses are observed, that are not yet covered and quantified by the available loss models. We find that the deviation increases with decreasing ice temperature. We suspect that this mismatch is mainly due to the too restrictive idealization of the probe model and the fact that the probe was not operated in an efficiency-optimized manner during the field tests. With respect to space mission engineering, we find that performance and efficiency models must be used with caution in unknown ice environments, as various ice parameters have a significant effect on the melting process. Some of these are difficult to estimate from afar. Y1 - 2023 U6 - http://dx.doi.org/10.1016/j.icarus.2023.115852 N1 - Forschungsdaten hierzu: "Performance data of an ice-melting probe from field tests in two different ice environments" (https://opus.bibliothek.fh-aachen.de/opus4/frontdoor/index/index/docId/10890) IS - 409 PB - Elsevier CY - Amsterdam ER -