@inproceedings{BaaderKellerLehmannetal.2019,
  author    = {Baader, Fabian and Keller, Denis and Lehmann, Raphael and Gerber, Lukas and Reiswich, Martin and Dachwald, Bernd and F{\"o}rstner, Roger},
  title     = {Operating melting probes for ice penetration under sublimation conditions and in reduced gravity on a sounding rocket},
  series = {Proceedings of the 24th ESA Symposium on European Rocket and Balloon Programmes and related Research},
  booktitle = {Proceedings of the 24th ESA Symposium on European Rocket and Balloon Programmes and related Research},
  issn      = {0379-6566},
  pages     = {8 Seiten},
  year      = {2019},
  language  = {en}
}
@inproceedings{BaaderReiswichBartschetal.2018,
  author    = {Baader, Fabian and Reiswich, M. and Bartsch, M. and Keller, D. and Tiede, E. and Keck, G. and Demircian, A. and Friedrich, M. and Dachwald, Bernd and Sch{\"u}ller, K. and Lehmann, R. and Chojetzki, R. and Durand, C. and Rapp, L. and Kowalski, Julia and F{\"o}rstner, R.},
  title     = {VIPER - Student research on extraterrestrical ice penetration technology},
  series = {Proceedings of the 2nd Symposium on Space Educational Activities},
  booktitle = {Proceedings of the 2nd Symposium on Space Educational Activities},
  pages     = {1 -- 6},
  year      = {2018},
  abstract  = {Recent analysis of scientific data from Cassini and earth-based observations gave evidence for a global ocean under a surrounding solid ice shell on Saturn's moon Enceladus. Images of Enceladus' South Pole showed several fissures in the ice shell with plumes constantly exhausting frozen water particles, building up the E-Ring, one of the outer rings of Saturn. In this southern region of Enceladus, the ice shell is considered to be as thin as 2 km, about an order of magnitude thinner than on the rest of the moon. Under the ice shell, there is a global ocean consisting of liquid water. Scientists are discussing different approaches the possibilities of taking samples of water, i.e. by melting through the ice using a melting probe. FH Aachen UAS developed a prototype of maneuverable melting probe which can navigate through the ice that has already been tested successfully in a terrestrial environment. This means no atmosphere and or ambient pressure, low ice temperatures of around 100 to 150K (near the South Pole) and a very low gravity of 0,114 m/s^2 or 1100 μg. Two of these influencing measures are about to be investigated at FH Aachen UAS in 2017, low ice temperature and low ambient pressure below the triple point of water. Low gravity cannot be easily simulated inside a large experiment chamber, though. Numerical simulations of the melting process at RWTH Aachen however are showing a gravity dependence of melting behavior. Considering this aspect, VIPER provides a link between large-scale experimental simulations at FH Aachen UAS and numerical simulations at RWTH Aachen. To analyze the melting process, about 90 seconds of experiment time in reduced gravity and low ambient pressure is provided by the REXUS rocket. In this time frame, the melting speed and contact force between ice and probes are measured, as well as heating power and a two-dimensional array of ice temperatures. Additionally, visual and infrared cameras are used to observe the melting process.},
  language  = {en}
}
@techreport{BlandfordDachwaldDigeletal.2015,
  author    = {Blandford, Daniel and Dachwald, Bernd and Digel, Ilya and Espe, Clemens and Feldmann, Marco and Francke, Gero and Hiecke, Hannah and Kowalski, Julia and Lindner, Peter and Plescher, Engelbert and Sch{\"o}ngarth, Sarah},
  title     = {Enceladus Explorer : Schlussbericht — Version: 1.0},
  publisher = {FH Aachen},
  address   = {Aachen},
  doi       = {10.2314/GBV:86319950X},
  year      = {2015},
  language  = {de}
}
@article{BlomeSeboldtDachwaldetal.2004,
  author    = {Blome, Hans-Joachim and Seboldt, Wolfgang and Dachwald, Bernd and Richter, Lutz},
  title     = {Proposal for an integrated European Space Exploration Study},
  series = {Space Debris and Space Traffic Management Symposium 2004 : proceedings of the International Academy of Astronautics Space Debris and Space Traffic Management Symposium, held in conjunction with the 55th International Astronautical Congress (IAC), October 4 - 8, 2004, Vancouver, British Columbia, Canada / ed. by Joerg Bendisch},
  journal   = {Space Debris and Space Traffic Management Symposium 2004 : proceedings of the International Academy of Astronautics Space Debris and Space Traffic Management Symposium, held in conjunction with the 55th International Astronautical Congress (IAC), October 4 - 8, 2004, Vancouver, British Columbia, Canada / ed. by Joerg Bendisch},
  publisher = {Univelt},
  address   = {San Diego, Calif.},
  isbn      = {0-87703-523-7},
  pages     = {XI, 432 S. : Ill., graph. Darst.},
  year      = {2004},
  language  = {en}
}
@incollection{BorggrafeOhndorfDachwaldetal.2012,
  author    = {Borggrafe, Andreas and Ohndorf, Andreas and Dachwald, Bernd and Seboldt, Wolfgang},
  title     = {Analysis of interplanetary solar sail trajectories with attitude dynamics},
  series = {Dynamics and Control of Space Systems 2012},
  booktitle = {Dynamics and Control of Space Systems 2012},
  publisher = {Univelt Inc},
  address   = {San Diego},
  isbn      = {978-0-87703-587-9},
  pages     = {1553 -- 1569},
  year      = {2012},
  abstract  = {We present a new approach to the problem of optimal control of solar sails for low-thrust trajectory optimization. The objective was to find the required control torque magnitudes in order to steer a solar sail in interplanetary space. A new steering strategy, controlling the solar sail with generic torques applied about the spacecraft body axes, is integrated into the existing low-thrust trajectory optimization software InTrance. This software combines artificial neural networks and evolutionary algorithms to find steering strategies close to the global optimum without an initial guess. Furthermore, we implement a three rotational degree-of-freedom rigid-body attitude dynamics model to represent the solar sail in space. Two interplanetary transfers to Mars and Neptune are chosen to represent typical future solar sail mission scenarios. The results found with the new steering strategy are compared to the existing reference trajectories without attitude dynamics. The resulting control torques required to accomplish the missions are investigated, as they pose the primary requirements to a real on-board attitude control system.},
  language  = {en}
}
@inproceedings{BorggraefeDachwald2010,
  author    = {Borggr{\"a}fe, Andreas and Dachwald, Bernd},
  title     = {Mission performance evaluation for solar sails using a refined SRP force model with variable optical coefficients},
  series = {2nd International Symposium on Solar Sailing},
  booktitle = {2nd International Symposium on Solar Sailing},
  pages     = {1 -- 6},
  year      = {2010},
  abstract  = {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.},
  language  = {en}
}
@article{CampenKowalskiLyonsetal.2019,
  author    = {Campen, R. and Kowalski, Julia and Lyons, W.B. and Tulaczyk, S. and Dachwald, Bernd and Pettit, E. and Welch, K. A. and Mikucki, J.A.},
  title     = {Microbial diversity of an Antarctic subglacial community and high-resolution replicate sampling inform hydrological connectivity in a polar desert},
  series = {Environmental Microbiology},
  journal   = {Environmental Microbiology},
  number    = {accepted article},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1462-2920},
  doi       = {10.1111/1462-2920.14607},
  year      = {2019},
  language  = {en}
}
@inproceedings{CarzanaDachwaldNoomen2017,
  author    = {Carzana, Livio and Dachwald, Bernd and Noomen, Ron},
  title     = {Model and trajectory optimization for an ideal laser-enhanced solar sail},
  series = {68th International Astronautical Congress},
  booktitle = {68th International Astronautical Congress},
  year      = {2017},
  abstract  = {A laser-enhanced solar sail is a solar sail that is not solely propelled by solar radiation but additionally by a laser beam that illuminates the sail. This way, the propulsive acceleration of the sail results from the combined action of the solar and the laser radiation pressure onto the sail. The potential source of the laser beam is a laser satellite that coverts solar power (in the inner solar system) or nuclear power (in the outer solar system) into laser power. Such a laser satellite (or many of them) can orbit anywhere in the solar system and its optimal orbit (or their optimal orbits) for a given mission is a subject for future research. This contribution provides the model for an ideal laser-enhanced solar sail and investigates how a laser can enhance the thrusting capability of such a sail. The term "ideal" means that the solar sail is assumed to be perfectly reflecting and that the laser beam is assumed to have a constant areal power density over the whole sail area. Since a laser beam has a limited divergence, it can provide radiation pressure at much larger solar distances and increase the radiation pressure force into the desired direction. Therefore, laser-enhanced solar sails may make missions feasible, that would otherwise have prohibitively long flight times, e.g. rendezvous missions in the outer solar system. This contribution will also analyze exemplary mission scenarios and present optimial trajectories without laying too much emphasis on the design and operations of the laser satellites. If the mission studies conclude that laser-enhanced solar sails would have advantages with respect to "traditional" solar sails, a detailed study of the laser satellites and the whole system architecture would be the second next step},
  language  = {en}
}
@article{Dachwald2005,
  author    = {Dachwald, Bernd},
  title     = {Optimization of very-low-thrust trajectories using evolutionary neurocontrol},
  series = {Acta Astronautica. 57 (2005), H. 2-8},
  journal   = {Acta Astronautica. 57 (2005), H. 2-8},
  isbn      = {0094-5765},
  pages     = {175 -- 185},
  year      = {2005},
  language  = {en}
}
@article{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Minimum Transfer Times for Nonperfectly Reflecting Solar Sailcraft},
  series = {Journal of Spacecraft and Rockets. 41 (2004), H. 4},
  journal   = {Journal of Spacecraft and Rockets. 41 (2004), H. 4},
  isbn      = {0022-4650},
  pages     = {693 -- 695},
  year      = {2004},
  language  = {en}
}
@article{Dachwald2005,
  author    = {Dachwald, Bernd},
  title     = {Optimal Solar Sail Trajectories for Missions to the Outer Solar System},
  series = {Journal of guidance, control, and dynamics. 28 (2005), H. 6},
  journal   = {Journal of guidance, control, and dynamics. 28 (2005), H. 6},
  isbn      = {0162-3192},
  pages     = {1187 -- 1193},
  year      = {2005},
  language  = {en}
}
@article{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Optimization of Interplanetary Solar Sailcraft Trajectories Using Evolutionary Neurocontrol},
  series = {Journal of guidance, control, and dynamics. 27 (2004), H. 1},
  journal   = {Journal of guidance, control, and dynamics. 27 (2004), H. 1},
  isbn      = {0162-3192},
  pages     = {66 -- 72},
  year      = {2004},
  language  = {en}
}
@article{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Interplanetary Mission Analysis for Non-Perfectly Reflecting Solar Sailcraft Using Evolutionary Neurocontrol},
  series = {Astrodynamics 2003 : proceedings of the AAS/AIAA Astrodynamics Conference held August 3 - 7, 2003, Big Sky, Montana / ed. by Jean de Lafontaine. - Pt. 2. - (Advances in the astronautical sciences ; 116,2)},
  journal   = {Astrodynamics 2003 : proceedings of the AAS/AIAA Astrodynamics Conference held August 3 - 7, 2003, Big Sky, Montana / ed. by Jean de Lafontaine. - Pt. 2. - (Advances in the astronautical sciences ; 116,2)},
  publisher = {Univelt},
  address   = {San Diego, Calif.},
  isbn      = {0-87703-509-1},
  pages     = {1247 -- 1262},
  year      = {2004},
  language  = {en}
}
@article{Dachwald2003,
  author    = {Dachwald, Bernd},
  title     = {Verwendung eines neuronalen Reglers und evolution{\"a}rer Algorithmen zur Berechnung optimaler interplanetarer Sonnenseglerbahnen},
  series = {Deutscher Luft- und Raumfahrtkongress 2003 : M{\"u}nchen, 17. bis 20. November 2003, Motto: 100 Jahre Motorflug - 112 Jahre Menschenflug: Visionen gestalten Zukunft / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. - Bd. 1. - (Jahrbuch ... der Deutschen Gesellschaft f{\"u}r Luft- und Raumfahrt)},
  journal   = {Deutscher Luft- und Raumfahrtkongress 2003 : M{\"u}nchen, 17. bis 20. November 2003, Motto: 100 Jahre Motorflug - 112 Jahre Menschenflug: Visionen gestalten Zukunft / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. - Bd. 1. - (Jahrbuch ... der Deutschen Gesellschaft f{\"u}r Luft- und Raumfahrt)},
  address   = {Bonn},
  pages     = {211 -- 218},
  year      = {2003},
  language  = {de}
}
@article{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Low-Thrust Trajectory Optimization and Interplanetary Mission Analysis Using Evolutionary Neurocontrol},
  series = {Deutscher Luft- und Raumfahrtkongress 2004 : Dresden, 20. bis 23. September 2004, Motto: Luft- und Raumfahrt - Br{\"u}cke f{\"u}r eine wissensbasierte Gesellschaft / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. - Bd. 2. - (Jahrbuch ... der Deutschen Gesellschaft f{\"u}r Luft- und Raumfahrt)},
  journal   = {Deutscher Luft- und Raumfahrtkongress 2004 : Dresden, 20. bis 23. September 2004, Motto: Luft- und Raumfahrt - Br{\"u}cke f{\"u}r eine wissensbasierte Gesellschaft / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. - Bd. 2. - (Jahrbuch ... der Deutschen Gesellschaft f{\"u}r Luft- und Raumfahrt)},
  address   = {Bonn},
  pages     = {917 -- 926},
  year      = {2004},
  language  = {en}
}
@article{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Evolutionary Neurocontrol: A Smart Method for Global Optimization of Low-Thrust Trajectories},
  series = {22nd AIAA Applied Aerodynamics Conference and Exhibit - AIAA/AAS Astrodynamics Specialist Conference and Exhibit - AIAA Guidance, Navigation, and Control Conference and Exhibit - AIAA Modeling and Simulation Technologies Conference and Exhibit - AIAA Atmospheric Flight Mechanics Conference and Exhibit : 16 - 19 August 2004, Providence, Rhode Island / American Institute of Aeronautics and Astronautics. - (AIAA meeting papers on disc ; 2004,14-15)},
  journal   = {22nd AIAA Applied Aerodynamics Conference and Exhibit - AIAA/AAS Astrodynamics Specialist Conference and Exhibit - AIAA Guidance, Navigation, and Control Conference and Exhibit - AIAA Modeling and Simulation Technologies Conference and Exhibit - AIAA Atmospheric Flight Mechanics Conference and Exhibit : 16 - 19 August 2004, Providence, Rhode Island / American Institute of Aeronautics and Astronautics. - (AIAA meeting papers on disc ; 2004,14-15)},
  publisher = {American Inst. of Aeronautics and Astronautics},
  address   = {Reston, Va.},
  pages     = {2 CD-ROMs},
  year      = {2004},
  language  = {en}
}
@article{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Optimal Solar Sail Trajectories for Missions to the Outer Solar System},
  series = {22nd AIAA Applied Aerodynamics Conference and Exhibit - AIAA/AAS Astrodynamics Specialist Conference and Exhibit - AIAA Guidance, Navigation, and Control Conference and Exhibit - AIAA Modeling and Simulation Technologies Conference and Exhibit - AIAA Atmospheric Flight Mechanics Conference and Exhibit : 16 - 19 August 2004, Providence, Rhode Island / American Institute of Aeronautics and Astronautics. - (AIAA meeting papers on disc ; 2004,14-15)},
  journal   = {22nd AIAA Applied Aerodynamics Conference and Exhibit - AIAA/AAS Astrodynamics Specialist Conference and Exhibit - AIAA Guidance, Navigation, and Control Conference and Exhibit - AIAA Modeling and Simulation Technologies Conference and Exhibit - AIAA Atmospheric Flight Mechanics Conference and Exhibit : 16 - 19 August 2004, Providence, Rhode Island / American Institute of Aeronautics and Astronautics. - (AIAA meeting papers on disc ; 2004,14-15)},
  publisher = {American Inst. of Aeronautics and Astronautics},
  address   = {Reston, Va.},
  pages     = {2 CD-ROMs},
  year      = {2004},
  language  = {en}
}
@inproceedings{Dachwald2007,
  author    = {Dachwald, Bernd},
  title     = {Low-Thrust Mission Analysis and Global Trajectory Optimization Using Evolutionary Neurocontrol: New Results},
  series = {European Workshop on Space Mission Analysis ESA/ESOC, Darmstadt, Germany 10 { 12 Dec 2007},
  booktitle = {European Workshop on Space Mission Analysis ESA/ESOC, Darmstadt, Germany 10 { 12 Dec 2007},
  year      = {2007},
  abstract  = {Interplanetary trajectories for low-thrust spacecraft are often characterized by multiple revolutions around the sun. Unfortunately, the convergence of traditional trajectory optimizers that are based on numerical optimal control methods depends strongly on an adequate initial guess for the control function (if a direct method is used) or for the starting values of the adjoint vector (if an indirect method is used). Especially when many revolutions around the sun are re- quired, trajectory optimization becomes a very difficult and time-consuming task that involves a lot of experience and expert knowledge in astrodynamics and optimal control theory, because an adequate initial guess is extremely hard to find. Evolutionary neurocontrol (ENC) was proposed as a smart method for low-thrust trajectory optimization that fuses artificial neural networks and evolutionary algorithms to so-called evolutionary neurocontrollers (ENCs) [1]. Inspired by natural archetypes, ENC attacks the trajectoryoptimization problem from the perspective of artificial intelligence and machine learning, a perspective that is quite different from that of optimal control theory. Within the context of ENC, a trajectory is regarded as the result of a spacecraft steering strategy that maps permanently the actual spacecraft state and the actual target state onto the actual spacecraft control vector. This way, the problem of searching the optimal spacecraft trajectory is equivalent to the problem of searching (or "learning") the optimal spacecraft steering strategy. An artificial neural network is used to implement such a spacecraft steering strategy. It can be regarded as a parameterized function (the network function) that is defined by the internal network parameters. Therefore, each distinct set of network parameters defines a different network function and thus a different steering strategy. The problem of searching the optimal steering strategy is now equivalent to the problem of searching the optimal set of network parameters. Evolutionary algorithms that work on a population of (artificial) chromosomes are used to find the optimal network parameters, because the parameters can be easily mapped onto a chromosome. The trajectory optimization problem is solved when the optimal chromosome is found. A comparison of solar sail trajectories that have been published by others [2, 3, 4, 5] with ENC-trajectories has shown that ENCs can be successfully applied for near-globally optimal spacecraft control [1, 6] and that they are able to find trajectories that are closer to the (unknown) global optimum, because they explore the trajectory search space more exhaustively than a human expert can do. The obtained trajectories are fairly accurate with respect to the terminal constraint. If a more accurate trajectory is required, the ENC-solution can be used as an initial guess for a local trajectory optimization method. Using ENC, low-thrust trajectories can be optimized without an initial guess and without expert attendance. Here, new results for nuclear electric spacecraft and for solar sail spacecraft are presented and it will be shown that ENCs find very good trajectories even for very difficult problems. Trajectory optimization results are presented for 1. NASA's Solar Polar Imager Mission, a mission to attain a highly inclined close solar orbit with a solar sail [7] 2. a mission to de ect asteroid Apophis with a solar sail from a retrograde orbit with a very-high velocity impact [8, 9] 3. JPL's \2nd Global Trajectory Optimization Competition", a grand tour to visit four asteroids from different classes with a NEP spacecraft},
  language  = {en}
}
@inproceedings{Dachwald2005,
  author    = {Dachwald, Bernd},
  title     = {Global optimization of low-thrust space missions using evolutionary neurocontrol},
  series = {Proceedings of the international workshop on global optimization},
  booktitle = {Proceedings of the international workshop on global optimization},
  pages     = {85 -- 90},
  year      = {2005},
  abstract  = {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.},
  language  = {en}
}
@incollection{Dachwald2017,
  author    = {Dachwald, Bernd},
  title     = {Light propulsion systems for spacecraft},
  series = {Optical nano and micro actuator technology},
  booktitle = {Optical nano and micro actuator technology},
  editor    = {Knopf, George K. and Otani, Yukitoshi},
  publisher = {CRC Press},
  address   = {Boca Raton},
  isbn      = {9781315217628 (eBook)},
  pages     = {577 -- 598},
  year      = {2017},
  language  = {en}
}
@incollection{Dachwald2010,
  author    = {Dachwald, Bernd},
  title     = {Solar sail dynamics and control},
  series = {Encyclopedia of Aerospace Engineering},
  booktitle = {Encyclopedia of Aerospace Engineering},
  publisher = {Wiley},
  address   = {Hoboken},
  doi       = {10.1002/9780470686652.eae292},
  year      = {2010},
  abstract  = {Solar sails are large and lightweight reflective structures that are propelled by solar radiation pressure. This chapter covers their orbital and attitude dynamics and control. First, the advantages and limitations of solar sails are discussed and their history and development status is outlined. Because the dynamics of solar sails is governed by the (thermo-)optical properties of the sail film, the basic solar radiation pressure force models have to be described and compared before parameters to measure solar sail performance can be defined. The next part covers the orbital dynamics of solar sails for heliocentric motion, planetocentric motion, and motion at Lagrangian equilibrium points. Afterwards, some advanced solar radiation pressure force models are described, which allow to quantify the thrust force on solar sails of arbitrary shape, the effects of temperature, of light incidence angle, of surface roughness, and the effects of optical degradation of the sail film in the space environment. The orbital motion of a solar sail is strongly coupled to its rotational motion, so that the attitude control of these soft and flexible structures is very challenging, especially for planetocentric orbits that require fast attitude maneuvers. Finally, some potential attitude control methods are sketched and selection criteria are given.},
  language  = {en}
}
@article{Dachwald2005,
  author    = {Dachwald, Bernd},
  title     = {Optimization of very-low-thrust trajectories using evolutionary neurocontrol},
  series = {Acta Astronautica},
  volume    = {57},
  journal   = {Acta Astronautica},
  number    = {2-8},
  publisher = {Elsevier},
  address   = {Amsterdam [u.a.]},
  isbn      = {1879-2030},
  pages     = {175 -- 185},
  year      = {2005},
  abstract  = {Searching optimal interplanetary trajectories for low-thrust spacecraft is usually a difficult and time-consuming task that involves much experience and expert knowledge in astrodynamics and optimal control theory. This is because the convergence behavior of traditional local optimizers, which are based on numerical optimal control methods, depends on an adequate initial guess, which is often hard to find, especially for very-low-thrust trajectories that necessitate many revolutions around the sun. The obtained solutions are typically close to the initial guess that is rarely close to the (unknown) global optimum. Within this paper, trajectory optimization problems are attacked from the perspective of artificial intelligence and machine learning. Inspired by natural archetypes, a smart global method for low-thrust trajectory optimization is proposed that fuses artificial neural networks and evolutionary algorithms into so-called evolutionary neurocontrollers. This novel method runs without an initial guess and does not require the attendance of an expert in astrodynamics and optimal control theory. This paper details how evolutionary neurocontrol works and how it could be implemented. The performance of the method is assessed for three different interplanetary missions with a thrust to mass ratio <0.15mN/kg (solar sail and nuclear electric).},
  language  = {en}
}
@inproceedings{Dachwald2017,
  author    = {Dachwald, Bernd},
  title     = {Radiation pressure force model for an ideal laser-enhanced solar sail},
  series = {4th International Symposium on Solar Sailing},
  booktitle = {4th International Symposium on Solar Sailing},
  pages     = {1 -- 5},
  year      = {2017},
  abstract  = {The concept of a laser-enhanced solar sail is introduced and the radiation pressure force model for an ideal laser-enhanced solar sail is derived. A laser-enhanced solar sail is a "traditional" solar sail that is, however, not solely propelled by solar radiation, but additionally by a laser beam that illuminates the sail. The additional laser radiation pressure increases the sail's propulsive force and can give, depending on the location of the laser source, more control authority over the direction of the solar sail's propulsive force vector. This way, laser-enhanced solar sails may augment already existing solar sail mission concepts and make novel mission concepts feasible.},
  language  = {en}
}
@inproceedings{Dachwald2004,
  author    = {Dachwald, Bernd},
  title     = {Solar sail performance requirements for missions to the outer solar system and beyond},
  series = {55th International Astronautical Congress 2004},
  booktitle = {55th International Astronautical Congress 2004},
  doi       = {10.2514/6.IAC-04-S.P.11},
  pages     = {1 -- 9},
  year      = {2004},
  abstract  = {Solar sails enable missions to the outer solar system and beyond, although the solar radiation pressure decreases with the square of solar distance. For such missions, the solar sail may gain a large amount of energy by first making one or more close approaches to the sun. Within this paper, optimal trajectories for solar sail missions to the outer planets and into near interstellar space (200 AU) are presented. Thereby, it is shown that even near/medium-term solar sails with relatively moderate performance allow reasonable transfer times to the boundaries of the solar system.},
  language  = {en}
}
@article{DachwaldBallUlamecetal.2009,
  author    = {Dachwald, Bernd and Ball, Andrew J. and Ulamec, Stephan and Price, Michael E.},
  title     = {A small mission for in situ exploration of a primitive binary near-Earth asteroid / Ball, Andrew J. ; Ulamec, Stephan ; Dachwald, Bernd ; Price, Michael E. ; [u.a.]},
  series = {Advances in Space Research. 43 (2009), H. 2},
  journal   = {Advances in Space Research. 43 (2009), H. 2},
  publisher = {Elsevier},
  address   = {Amsterdam},
  isbn      = {0273-1177},
  pages     = {317 -- 324},
  year      = {2009},
  language  = {en}
}
@inproceedings{DachwaldBaturkinCoverstoneetal.2005,
  author    = {Dachwald, Bernd and Baturkin, Volodymyr and Coverstone, Victoria and Diedrich, Ben and Garbe, Gregory and G{\"o}rlich, Marianne and Leipold, Manfred and Lura, Franz and Macdonald, Malcolm and McInnes, Colin and Mengali, Giovanni and Quarta, Alessandro and Rios-Reyes, Leonel and Scheeres, Daniel J. and Seboldt, Wolfgang and Wie, Bong},
  title     = {Potential effects of optical solar sail degredation on trajectory design},
  series = {AAS/AIAA Astrodynamics Specialist},
  booktitle = {AAS/AIAA Astrodynamics Specialist},
  pages     = {1 -- 23},
  year      = {2005},
  abstract  = {The optical properties of the thin metalized polymer films that are projected for solar sails are assumed to be affected by the erosive effects of the space environment. Their degradation behavior in the real space environment, however, is to a considerable degree indefinite, because initial ground test results are controversial and relevant inspace tests have not been made so far. The standard optical solar sail models that are currently used for trajectory design do not take optical degradation into account, hence its potential effects on trajectory design have not been investigated so far. Nevertheless, optical degradation is important for high-fidelity solar sail mission design, because it decreases both the magnitude of the solar radiation pressure force acting on the sail and also the sail control authority. Therefore, we propose a simple parametric optical solar sail degradation 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. Using our model, the effects of different optical degradation behaviors on trajectory design are investigated for various exemplary missions.},
  language  = {en}
}
@article{DachwaldBaturkinCoverstoneetal.2006,
  author    = {Dachwald, Bernd and Baturkin, Volodymyr and Coverstone, Victoria L. and Dietrich, Benjamin and Garbe, Gregory P. and G{\"o}rlich, Marianne and Leipold, Manfred and Lura, Franz and Macdonald, Malcolm and McInnes, Colin R. and Mengali, Giovanni and Quatra, Alessandro A. and Rios-Reyes, Leonel and Scheeres, Daniel J. and Seboldt, Wolfgang and Wie, Bong},
  title     = {Potential Effects of Optical Solar Sail Degradation on Interplanetary Trajectory Design},
  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     = {2569 -- 2592},
  year      = {2006},
  language  = {en}
}
@incollection{DachwaldBoehnhardtBrojetal.2014,
  author    = {Dachwald, Bernd and Boehnhardt, Herrmann and Broj, Ulrich and Geppert, Ulrich R. M. E. and Grundmann, Jan-Thimo and Seboldt, Wolfgang and Seefeldt, Patric and Spietz, Peter and Johnson, Les and K{\"u}hrt, Ekkehard and Mottola, Stefano and Macdonald, Malcolm and McInnes, Colin R. and Vasile, Massimiliano and Reinhard, Ruedeger},
  title     = {Gossamer roadmap technology reference study for a multiple NEO Rendezvous Mission},
  series = {Advances in solar sailing},
  booktitle = {Advances in solar sailing},
  publisher = {Springer},
  address   = {Berlin [u.a.]},
  isbn      = {978-3-642-34906-5 (Print) ; 978-3-642-34907-2 (E-Book)},
  pages     = {211 -- 226},
  year      = {2014},
  abstract  = {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.},
  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}
}
@article{DachwaldCarnelliVasile2007,
  author    = {Dachwald, Bernd and Carnelli, I. and Vasile, M.},
  title     = {Optimizing low-thrust gravity assist interplanetary trajectories using evolutionary neurocontrollers / I. Carnelli ; B. Dachwald ; M. Vasile},
  series = {IEEE Congress on Evolutionary Computation, 2007 : CEC 2007 ; 25 - 28 September 2007, Singapore},
  journal   = {IEEE Congress on Evolutionary Computation, 2007 : CEC 2007 ; 25 - 28 September 2007, Singapore},
  publisher = {IEEE Service Center},
  address   = {Piscataway, NJ},
  isbn      = {978-1-424-41339-3},
  pages     = {965 -- 972},
  year      = {2007},
  language  = {en}
}
@article{DachwaldCarnelliVasile2006,
  author    = {Dachwald, Bernd and Carnelli, I. and Vasile, M.},
  title     = {Evolutionary Neurocontrol as a Novel Method for Low-Thrust Gravity Assist Trajectory Optimization / I. Carnelli ; B. Dachwald ; M. Vasile},
  series = {Proceedings of the Twenty-Fifth International Symposium on Space Technology and Science (Selected papers) : Kanazawa, [June 4 through June 11, 2006, at Kanazawa-shi Kanko Kaikan in Kanazawa city] / [Japan Society for Aeronautical and Space Sciences. Kohtaro Matsumoto [ed.-in-chief]},
  journal   = {Proceedings of the Twenty-Fifth International Symposium on Space Technology and Science (Selected papers) : Kanazawa, [June 4 through June 11, 2006, at Kanazawa-shi Kanko Kaikan in Kanazawa city] / [Japan Society for Aeronautical and Space Sciences. Kohtaro Matsumoto [ed.-in-chief]},
  publisher = {JSASS},
  address   = {Tokyo},
  isbn      = {4-99005-002-9},
  pages     = {569 -- 574},
  year      = {2006},
  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}
}
@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{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}
}
@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{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{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{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}
}
@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.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{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{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}
}
@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{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{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{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}
}
@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{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}
}