@article{DachwaldSchmidtSeboldtetal.2003,
  author    = {Dachwald, Bernd and Schmidt, Tanja D. and Seboldt, Wolfgang and Auweter-Kurtz,},
  title     = {Flight Opportunities from Mars to Earth for Piloted Missions Using Continuous Thrust Propulsion / Schmidt, Tanja D. ; Dachwald, Bernd ; Seboldt, Wolfgang ; Auweter-Kurtz, Monika},
  publisher = {-},
  pages     = {1 -- 9},
  year      = {2003},
  language  = {en}
}
@incollection{DachwaldOhndorf2019,
  author    = {Dachwald, Bernd and Ohndorf, Andreas},
  title     = {Global optimization of continuous-thrust trajectories using evolutionary neurocontrol},
  series = {Modeling and Optimization in Space Engineering},
  booktitle = {Modeling and Optimization in Space Engineering},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-030-10501-3},
  doi       = {10.1007/978-3-030-10501-3_2},
  pages     = {33 -- 57},
  year      = {2019},
  abstract  = {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.},
  language  = {en}
}
@article{DachwaldOhndorfWie2006,
  author    = {Dachwald, Bernd and Ohndorf, A. and Wie, Bong},
  title     = {Solar Sail Trajectory Optimization for the Solar Polar Imager (SPI) Mission},
  series = {AIAA Guidance, Navigation, and Control Conference \& Exhibit - AIAA Atmospheric Flight Mechanics Conference \& Exhibit - AIAA Modeling and Simulation Technologies Conference \& Exhibit - AIAA/AAS Astrodynamics Specialist Conference \& Exhibit : [21 - 24 August 2006, Keystone, Colorado ; papers]. - (AIAA meeting papers on disc ; [11.]2006,19-20 )},
  journal   = {AIAA Guidance, Navigation, and Control Conference \& Exhibit - AIAA Atmospheric Flight Mechanics Conference \& Exhibit - AIAA Modeling and Simulation Technologies Conference \& Exhibit - AIAA/AAS Astrodynamics Specialist Conference \& Exhibit : [21 - 24 August 2006, Keystone, Colorado ; papers]. - (AIAA meeting papers on disc ; [11.]2006,19-20 )},
  publisher = {American Institute of Aeronautics and Astronautics},
  address   = {Reston, Va.},
  isbn      = {1-56347-802-1},
  pages     = {2 CD-ROMs.},
  year      = {2006},
  language  = {en}
}
@article{DachwaldOhndorfSeboldt2005,
  author    = {Dachwald, Bernd and Ohndorf, A. and Seboldt, W.},
  title     = {Optimierung der Lageregelung von Raumfahrzeugen mit Niedrigschubantrieb mittels evolution{\"a}rer neuronaler Regler / A. Ohndorf ; B. Dachwald ; W. Seboldt},
  series = {Deutscher Luft- und Raumfahrtkongress 2005 : Friedrichshafen, 26. bis 29. September 2005, Motto: Luft- und Raumfahrt - Grenzen {\"u}berwinden, Horizonte erweitern / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. Bd. 3. - (Jahrbuch ... der Deutschen Gesellschaft f{\"u}r Luft- und Raumfahrt},
  journal   = {Deutscher Luft- und Raumfahrtkongress 2005 : Friedrichshafen, 26. bis 29. September 2005, Motto: Luft- und Raumfahrt - Grenzen {\"u}berwinden, Horizonte erweitern / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. Bd. 3. - (Jahrbuch ... der Deutschen Gesellschaft f{\"u}r Luft- und Raumfahrt},
  publisher = {DGLR},
  address   = {Bonn},
  pages     = {1971 -- 1978},
  year      = {2005},
  language  = {de}
}
@article{DachwaldOhndorfGill2009,
  author    = {Dachwald, Bernd and Ohndorf, A. and Gill, E.},
  title     = {Optimization of low-thrust Earth-Moon transfers using evolutionary neurocontrol / Ohndorf, A. ; Dachwald, B. ; Gill, E.},
  series = {IEEE Congress on Evolutionary Computation, 2009. CEC '09.},
  journal   = {IEEE Congress on Evolutionary Computation, 2009. CEC '09.},
  isbn      = {978-1-4244-2958-5},
  pages     = {358 -- 364},
  year      = {2009},
  language  = {en}
}
@article{DachwaldOhndorf2007,
  author    = {Dachwald, Bernd and Ohndorf, A.},
  title     = {1st ACT Global Trajectory Optimisation Competition : Results found at DLR},
  series = {Acta Astronautica. 61 (2007), H. 9},
  journal   = {Acta Astronautica. 61 (2007), H. 9},
  isbn      = {0094-5765},
  pages     = {742 -- 752},
  year      = {2007},
  language  = {en}
}
@article{DachwaldMikuckiTulaczyketal.2014,
  author    = {Dachwald, Bernd and Mikucki, Jill and Tulaczyk, Slawek and Digel, Ilya and Espe, Clemens and Feldmann, Marco and Francke, Gero and Kowalski, Julia and Xu, Changsheng},
  title     = {IceMole : A maneuverable probe for clean in situ analysis and sampling of subsurface ice and subglacial aquatic ecosystems},
  series = {Annals of Glaciology},
  volume    = {55},
  journal   = {Annals of Glaciology},
  number    = {65},
  publisher = {Cambridge University Press},
  address   = {Cambridge},
  issn      = {1727-5644},
  doi       = {10.3189/2014AoG65A004},
  pages     = {14 -- 22},
  year      = {2014},
  abstract  = {There is significant interest in sampling subglacial environments for geobiological studies, but they are difficult to access. Existing ice-drilling technologies make it cumbersome to maintain microbiologically clean access for sample acquisition and environmental stewardship of potentially fragile subglacial aquatic ecosystems. The IceMole is a maneuverable subsurface ice probe for clean in situ analysis and sampling of glacial ice and subglacial materials. The design is based on the novel concept of combining melting and mechanical propulsion. It can change melting direction by differential heating of the melting head and optional side-wall heaters. The first two prototypes were successfully tested between 2010 and 2012 on glaciers in Switzerland and Iceland. They demonstrated downward, horizontal and upward melting, as well as curve driving and dirt layer penetration. A more advanced probe is currently under development as part of the Enceladus Explorer (EnEx) project. It offers systems for obstacle avoidance, target detection, and navigation in ice. For the EnEx-IceMole, we will pay particular attention to clean protocols for the sampling of subglacial materials for biogeochemical analysis. We plan to use this probe for clean access into a unique subglacial aquatic environment at Blood Falls, Antarctica, with return of a subglacial brine sample.},
  language  = {en}
}
@inproceedings{DachwaldMikuckiTulaczyketal.2012,
  author    = {Dachwald, Bernd and Mikucki, Jill A. and Tulaczyk, Slawek and Digel, Ilya and Feldmann, Marco and Espe, Clemens and Plescher, Engelbert and Xu, Changsheng},
  title     = {IceMole - a maneuverable probe for clean in-situ analysis and sampling of subsurface ice and subglacial aquatic ecosystems : extended abstract / SCAR Open Science Conference 2012, Session 29: Advancing Clean Technologies for Exploration of Glacial Aquatic Ecosystems},
  year      = {2012},
  abstract  = {The "IceMole" is a novel maneuverable subsurface ice probe for clean in-situ analysis and sampling of subsurface ice and subglacial water/brine. It is developed and build at FH Aachen University of Applied Sciences' Astronautical Laboratory. A first prototype was successfully tested on the Swiss Morteratsch glacier in 2010. Clean sampling is achieved with a hollow ice screw (as it is used in mountaineering) at the tip of the probe. Maneuverability is achieved with a differentially heated melting head. Funded by the German Space Agency (DLR), a consortium led by FH Aachen currently develops a much more advanced IceMole probe, which includes a sophisticated system for obstacle avoidance, target detection, and navigation in the ice. We intend to use this probe for taking clean samples of subglacial brine at the Blood Falls (McMurdo Dry Valleys, East Antarctica) for chemical and microbiological analysis. In our conference contribution, we 1) describe the IceMole design, 2) report the results of the field tests of the first prototype on the Morteratsch glacier, 3) discuss the probe's potential for the clean in-situ analysis and sampling of subsurface ice and subglacial liquids, and 4) outline the way ahead in the development of this technology.},
  subject      = {Eisschicht},
  language  = {en}
}
@article{DachwaldMengaliQuartaetal.2007,
  author    = {Dachwald, Bernd and Mengali, Giovanni and Quarta, Alessandro A. and Circi, Christian},
  title     = {Refined Solar Sail Force Model with Mission Application / Giovanni Mengali ; Alessandro A. Quarta , Christian Circi ; Bernd Dachwald},
  series = {Journal of Guidance, Control, and Dynamics. 30 (2007), H. 2},
  journal   = {Journal of Guidance, Control, and Dynamics. 30 (2007), H. 2},
  isbn      = {0162-3192},
  pages     = {512 -- 520},
  year      = {2007},
  language  = {en}
}
@inproceedings{DachwaldMengaliQuartaetal.2007,
  author    = {Dachwald, Bernd and Mengali, Giovanni and Quarta, Alessandro A and Macdonald, Malcolm and McInnes, Colin R},
  title     = {Optical solar sail degradation modelling},
  series = {1st International Symposium on Solar Sailing},
  booktitle = {1st International Symposium on Solar Sailing},
  pages     = {1 -- 27},
  year      = {2007},
  abstract  = {We propose a simple parametric OSSD model that describes the variation of the sail film's optical coefficients with time, depending on the sail film's environmental history, i.e., the radiation dose. The primary intention of our model is not to describe the exact behavior of specific film-coating combinations in the real space environment, but to provide a more general parametric framework for describing the general optical degradation behavior of solar sails.},
  language  = {en}
}
@article{DachwaldMengaliQuartaetal.2006,
  author    = {Dachwald, Bernd and Mengali, Giovanni and Quarta, Alessandrao A. and Macdonald, Malcolm},
  title     = {Parametric Model and Optimal Control of Solar Sails with Optical Degradation},
  series = {Journal of guidance, control, and dynamics. 29 (2006), H. 5},
  journal   = {Journal of guidance, control, and dynamics. 29 (2006), H. 5},
  isbn      = {0162-3192},
  pages     = {1170 -- 1178},
  year      = {2006},
  language  = {en}
}
@article{DachwaldMcDonaldMcInnesetal.2007,
  author    = {Dachwald, Bernd and McDonald, Malcolm and McInnes, Colin R. and Mengali, Giovanni},
  title     = {Impact of Optical Degradation on Solar Sail Mission Performance},
  series = {Journal of Spacecraft and Rockets. 44 (2007), H. 4},
  journal   = {Journal of Spacecraft and Rockets. 44 (2007), H. 4},
  isbn      = {0022-4650},
  pages     = {740 -- 749},
  year      = {2007},
  language  = {en}
}
@article{DachwaldMacDonaldMcInnes2007,
  author    = {Dachwald, Bernd and MacDonald, Malcolm and McInnes, Colin R.},
  title     = {Heliocentric Solar Sail Orbit Transfers with Locally Optimal Control Laws / Malcolm Macdonald ; Colin McInnes ; Bernd Dachwald},
  series = {Journal of Spacecraft and Rockets. 44 (2007), H. 1},
  journal   = {Journal of Spacecraft and Rockets. 44 (2007), H. 1},
  isbn      = {0022-4650},
  pages     = {273 -- 276},
  year      = {2007},
  language  = {en}
}
@article{DachwaldLeipoldFichtner2003,
  author    = {Dachwald, Bernd and Leipold, M. and Fichtner, H.},
  title     = {Heliopause Explorer - A Sailcraft Mission to the Outer Boundaries of the Solar System / M. Leipold ; H. Fichtner ; B. Heber ... B. Dachwald ...},
  series = {Proceedings of the Fifth IAA International Conference on Low Cost Planetary Missions : 24 - 26 September 2003, ESTEC, Noordwijk, the Netherlands / [comp. by R. A. Harris]},
  journal   = {Proceedings of the Fifth IAA International Conference on Low Cost Planetary Missions : 24 - 26 September 2003, ESTEC, Noordwijk, the Netherlands / [comp. by R. A. Harris]},
  publisher = {ESA},
  address   = {Noordwijk},
  isbn      = {92-9092-853-0},
  pages     = {367 -- 375},
  year      = {2003},
  language  = {en}
}
@article{DachwaldKahleWie2006,
  author    = {Dachwald, Bernd and Kahle, Ralph and Wie, Bong},
  title     = {Solar Sailing Kinetic Energy Impactor (KEI) Mission Design Tradeoffs for Impacting and Deflecting Asteroid 99942 Apophis},
  series = {AIAA Guidance, Navigation, and Control Conference \& Exhibit - AIAA Atmospheric Flight Mechanics Conference \& Exhibit - AIAA Modeling and Simulation Technologies Conference \& Exhibit - AIAA/AAS Astrodynamics Specialist Conference \& Exhibit : [21 - 24 August 2006, Keystone, Colorado ; papers]. - (AIAA meeting papers on disc ; [11.]2006,19-20 )},
  journal   = {AIAA Guidance, Navigation, and Control Conference \& Exhibit - AIAA Atmospheric Flight Mechanics Conference \& Exhibit - AIAA Modeling and Simulation Technologies Conference \& Exhibit - AIAA/AAS Astrodynamics Specialist Conference \& Exhibit : [21 - 24 August 2006, Keystone, Colorado ; papers]. - (AIAA meeting papers on disc ; [11.]2006,19-20 )},
  publisher = {American Institute of Aeronautics and Astronautics},
  address   = {Reston, Va.},
  isbn      = {1-56347-802-1},
  pages     = {1 -- 20},
  year      = {2006},
  language  = {en}
}
@inproceedings{DachwaldKahleWie2006,
  author    = {Dachwald, Bernd and Kahle, Ralph and Wie, Bong},
  title     = {Solar sail Kinetic Energy Impactor (KEI) mission design tradeoffs for impacting and deflecting asteroid 99942 Apophis},
  series = {AIAA/AAS Astrodynamics Specialist Conference and Exhibit},
  booktitle = {AIAA/AAS Astrodynamics Specialist Conference and Exhibit},
  doi       = {10.2514/6.2006-6178},
  pages     = {1 -- 20},
  year      = {2006},
  abstract  = {Near-Earth asteroid 99942 Apophis provides a typical example for the evolution of asteroid orbits that lead to Earth-impacts after a close Earth-encounter that results in a resonant return. Apophis will have a close Earth-encounter in 2029 with potential very close subsequent Earth-encounters (or even an impact) in 2036 or later, depending on whether it passes through one of several so-called gravitational keyholes during its 2029-encounter. Several pre-2029-deflection scenarios to prevent Apophis from doing this have been investigated so far. Because the keyholes are less than 1 km in size, a pre-2029 kinetic impact is clearly the best option because it requires only a small change in Apophis' orbit to nudge it out of a keyhole. A single solar sail Kinetic Energy Impactor (KEI) spacecraft that impacts Apophis from a retrograde trajectory with a very high relative velocity (75-80 km/s) during one of its perihelion passages at about 0.75 AU would be a feasible option to do this. The spacecraft consists of a 160 m x 160 m, 168 kg solar sail assembly and a 150 kg impactor. Although conventional spacecraft can also achieve the required minimum deflection of 1 km for this approx. 320 m-sized object from a prograde trajectory, our solar sail KEI concept also allows the deflection of larger objects. In this paper, we also show that, even after Apophis has flown through one of the gravitational keyholes in 2029, solar sail Kinetic Energy Impactor (KEI) spacecraft are still a feasible option to prevent Apophis from impacting the Earth, but many KEIs would be required for consecutive impacts to increase the total Earth-miss distance to a safe value. In this paper, we elaborate potential pre- and post-2029 KEI impact scenarios for a launch in 2020, and investigate tradeoffs between different mission parameters.},
  language  = {en}
}
@inproceedings{DachwaldKahleWie2007,
  author    = {Dachwald, Bernd and Kahle, Ralph and Wie, Bong},
  title     = {Head-on impact deflection of NEAs: a case study for 99942 Apophis},
  series = {Planetary Defense Conference 2007},
  booktitle = {Planetary Defense Conference 2007},
  pages     = {1 -- 12},
  year      = {2007},
  abstract  = {Near-Earth asteroid (NEA) 99942 Apophis provides a typical example for the evolution of asteroid orbits that lead to Earth-impacts after a close Earth-encounter that results in a resonant return. Apophis will have a close Earth-encounter in 2029 with potential very close subsequent Earth-encounters (or even an impact) in 2036 or later, depending on whether it passes through one of several less than 1 km-sized gravitational keyholes during its 2029-encounter. A pre-2029 kinetic impact is a very favorable option to nudge the asteroid out of a keyhole. The highest impact velocity and thus deflection can be achieved from a trajectory that is retrograde to Apophis orbit. With a chemical or electric propulsion system, however, many gravity assists and thus a long time is required to achieve this. We show in this paper that the solar sail might be the better propulsion system for such a mission: a solar sail Kinetic Energy Impactor (KEI) spacecraft could impact Apophis from a retrograde trajectory with a very high relative velocity (75-80 km/s) during one of its perihelion passages. The spacecraft consists of a 160 m × 160 m, 168 kg solar sail assembly and a 150 kg impactor. Although conventional spacecraft can also achieve the required minimum deflection of 1 km for this approx. 320 m-sized object from a prograde trajectory, our solar sail KEI concept also allows the deflection of larger objects. For a launch in 2020, we also show that, even after Apophis has flown through one of the gravitational keyholes in 2029, the solar sail KEI concept is still feasible to prevent Apophis from impacting the Earth, but many KEIs would be required for consecutive impacts to increase the total Earth-miss distance to a safe value},
  language  = {en}
}
@inproceedings{DachwaldFeldmannEspeetal.2012,
  author    = {Dachwald, Bernd and Feldmann, Marco and Espe, Clemens and Plescher, Engelbert and Konstantinidis, K. and Forstner, R.},
  title     = {Enceladus explorer - A maneuverable subsurface probe for autonomous navigation through deep ice},
  series = {63rd International Astronautical Congress 2012, IAC 2012; Naples; Italy; 1 October 2012 through 5 October 2012. (Proceedings of the International Astronautical Congress, IAC ; 3)},
  booktitle = {63rd International Astronautical Congress 2012, IAC 2012; Naples; Italy; 1 October 2012 through 5 October 2012. (Proceedings of the International Astronautical Congress, IAC ; 3)},
  publisher = {Curran},
  address   = {Red Hook, NY},
  organization    = {International Astronautical Congress <63, 2012, Napoli>},
  isbn      = {978-1-62276-979-7},
  pages     = {1756 -- 1766},
  year      = {2012},
  language  = {en}
}
@article{DachwaldCarnelliVasile2009,
  author    = {Dachwald, Bernd and Carnelli, Ian and Vasile, Massimiliano},
  title     = {Evolutionary Neurocontrol: A Novel Method for Low-Thrust Gravity-Assist Trajectory Optimization / Carnelli, Ian ; Dachwald, Bernd ; Vasile, Massimiliano},
  series = {Journal of guidance control and dynamics. 32 (2009), H. 2},
  journal   = {Journal of guidance control and dynamics. 32 (2009), H. 2},
  publisher = {AIAA},
  address   = {Reston, Va.},
  isbn      = {0731-5090},
  pages     = {616 -- 625},
  year      = {2009},
  language  = {en}
}
@article{DachwaldCarnelliVasile2006,
  author    = {Dachwald, Bernd and Carnelli, I. and Vasile, M.},
  title     = {Low-Thrust Gravity Assist Trajectory Optimization Using Evolutionary Neurocontrollers / I. Carnelli ; B. Dachwald ; M. Vasile ...},
  series = {Astrodynamics 2005 : proceedings of the AAS/AIAA astrodynamics conference held August 7 - 11, 2005, South Lake Tahoe, California / ed. by Bobby G. Williams. - Pt. 3. - (Advances in the astronautical sciences ; 123,3)},
  journal   = {Astrodynamics 2005 : proceedings of the AAS/AIAA astrodynamics conference held August 7 - 11, 2005, South Lake Tahoe, California / ed. by Bobby G. Williams. - Pt. 3. - (Advances in the astronautical sciences ; 123,3)},
  publisher = {Univelt},
  address   = {San Diego, Calif.},
  isbn      = {0-87703-527-X},
  pages     = {1911 -- 1928},
  year      = {2006},
  language  = {en}
}