TY  - JOUR
A1  - Dachwald, Bernd
A1  - Tsinas, L.
T1  - A combined neural and genetic learning algorithm / Tsinas, L. ; Dachwald, B.
JF  - Proceedings of the First IEEE Conference on  Evolutionary Computation, 1994. IEEE World Congress on Computational Intelligence.
Y1  - 1994
SN  - 0-7803-1899-4
SP  - 770
EP  - 774
CY  - Orlando, Fl
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Entwicklung sicherer und wartbarer Software für den Eurofighter
JF  - Soldat und Technik : Strategie und Technik, Sicherheit (1996)
Y1  - 1996
SN  - 0038-0989
SP  - 663
EP  - 668
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Seboldt, W.
T1  - Optimization of Interplanetary Rendezvous Trajectories for Solar Sailcraft Using a Neurocontroller
JF  - A collection of technical papers / AIAA Astrodynamics Specialist Conference : Monterey, California, 5 - 8 August 2002. - Vol. 2
Y1  - 2002
SN  - 1-56347-549-9
N1  - Astrodynamics Specialist Conference <2002, Monterey, Calif.> American Institute of Aeronautics and Astronautics <Reston, Va.>  ; AIAA  paper number: AIAA-2002-4989
SP  - 1263
EP  - 1270
PB  - American Institute of Aeronautics and Astronautics
CY  - Reston, Va.
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
A1  - Häusler, Bernd
T1  - Performance requirements for near-term interplanetary solar sailcraft missions
T2  - 6th International AAAF Symposium on Space Propulsion: Propulsion for Space Transportation of the XXIst Century
N2  - Solar sailcraft provide a wide range of opportunities for high-energy low-cost missions. To date, most mission studies require a rather demanding performance that will not be realized by solar sailcraft of the first generation.
However, even with solar sailcraft of moderate performance, scientifically relevant missions are feasible. This is demonstrated with a Near Earth Asteroid sample return mission and various planetary rendezvous missions.
Y1  - 2002
N1  - 6th International AAAF Symposium on Space Propulsion: Propulsion for Space Transportation of the XXIst Century, Versailles, France, 14-16 May 2002
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Seboldt, W.
A1  - Richter, L.
T1  - Multiple Rendezvous and Sample Return Missions to Near-Earth Asteroids Using Solar Sailcraft
JF  - 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]
Y1  - 2003
SN  - 92-9092-853-0
N1  - International Conference on Low Cost Planetary Missions <5, 2003, Noordwijk> ; International Academy of Astronautics ; European Space Research and Technology Centre
SP  - 351
EP  - 358
PB  - ESA
CY  - Noordwijk
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Verwendung eines neuronalen Reglers und evolutionärer Algorithmen zur Berechnung optimaler interplanetarer Sonnenseglerbahnen
JF  - Deutscher Luft- und Raumfahrtkongress 2003 : München, 17. bis 20. November 2003, Motto: 100 Jahre Motorflug - 112 Jahre Menschenflug: Visionen gestalten Zukunft / Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. - Bd. 1. - (Jahrbuch ... der Deutschen Gesellschaft für Luft- und Raumfahrt)
Y1  - 2003
N1  - Deutscher Luft- und Raumfahrt-Kongreß <2003, München> ; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth ; DGLR-2002-089
SP  - 211
EP  - 218
CY  - Bonn
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Leipold, M.
A1  - Fichtner, H.
T1  - Heliopause Explorer - A Sailcraft Mission to the Outer Boundaries of the Solar System / M. Leipold ; H. Fichtner ; B. Heber  ... B. Dachwald ...
JF  - 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]
Y1  - 2003
SN  - 92-9092-853-0
N1  - International Conference on Low Cost Planetary Missions <5, 2003, Noordwijk> ; International Academy of Astronautics ; European Space Research and Technology Centre
SP  - 367
EP  - 375
PB  - ESA
CY  - Noordwijk
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
T1  - Solar sailcraft of the first generation technology development / Seboldt, Wolfgang ; Dachwald, Bernd
Y1  - 2003
N1  - 54th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law 29 September - 3 October 2003, Bremen, Germany IAC-03-S.03
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
T1  - Solar sailcraft of the first generation mission applications to near-earth asteroids
Y1  - 2003
N1  - 54th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law 29 September - 3 October 2003, Bremen, Germany IAC-03-Q.5.06
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  - CHAP
A1  - Seboldt, Wolfgang
A1  - Dachwald, Bernd
T1  - Solar sails for near-term advanced scientific deep space missions
T2  - Proceedings of the 8th International Workshop on Combustion and Propulsion
N2  - Solar sails are propelled in space by reflecting solar photons off large mirroring surfaces, thereby transforming the momentum of the photons into a propulsive force. This innovative concept for low-thrust space propulsion works without any propellant and thus provides a wide range of opportunities for highenergy low-cost missions. Offering an efficient way of propulsion, solar sailcraft could close a gap in transportation options for highly demanding exploration missions within our solar system and even beyond. On December 17th, 1999, a significant step was made towards the realization of this technology: a lightweight solar sail structure with an area of 20 m × 20 m was successfully deployed on ground in a large facility at the German Aerospace Center (DLR) at Cologne. The deployment from a package of 60 cm × 60 cm × 65 cm with a total mass of less than 35 kg was achieved using four extremely light-weight carbon fiber reinforced plastics (CFRP) booms with a specific mass of 100 g/m. The paper briefly reviews the basic principles of solar sails as well as the technical concept and its realization in the ground demonstration experiment, performed in close cooperation between DLR and ESA. Next possible steps are outlined. They could comprise the in-orbit demonstration of the sail deployment on the upper stage of a low-cost rocket and the verification of the propulsion concept by an autonomous and free flying solar sail in the frame of a scientific mission. It is expected that the present design could be extended to sail sizes of about (40 m)2  up to even (70 m)2 without significant mass penalty. With these areas, the maximum achievable thrust at 1 AU would range between 10 and 40 mN – comparable to some electric thrusters. Such prototype sails with a mass between 50 and 150 kg plus a micro-spacecraft of 50 to 250 kg would have a maximum acceleration in the order of 0.1 mm/s2 at 1 AU, corresponding to a maximum ∆V-capability of about 3 km/s per year. Two near/medium-term mission examples to a near-Earth asteroid (NEA) will be discussed: a rendezvous mission
and a sample return mission.
KW  - solar sail
KW  - low-thrust
KW  - near-Earth asteroid
KW  - sample return
KW  - solar system
Y1  - 2003
N1  - Proceedings of the 8th International Workshop on Combustion and Propulsion. Pozzuoli, Italy, 16 - 21 June 2002.
ER  - 
TY  - JOUR
A1  - Blome, Hans-Joachim
A1  - Seboldt, Wolfgang
A1  - Dachwald, Bernd
A1  - Richter, Lutz
T1  - Proposal for an integrated European Space Exploration Study
JF  - 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
Y1  - 2004
SN  - 0-87703-523-7
N1  - Proceedings IAC-2004-IAA, 3.6.1.06; Space Debris and Space Traffic Management Symposium <2004, Vancouver, British Columbia> ; International Academy of Astronautics
PB  - Univelt
CY  - San Diego, Calif.
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Minimum Transfer Times for Nonperfectly Reflecting Solar Sailcraft
JF  - Journal of Spacecraft and Rockets. 41 (2004), H. 4
Y1  - 2004
SN  - 0022-4650
N1  - 2. ISSN: 1533-6794
SP  - 693
EP  - 695
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Optimization of Interplanetary Solar Sailcraft Trajectories Using Evolutionary Neurocontrol
JF  - Journal of guidance, control, and dynamics. 27 (2004), H. 1
Y1  - 2004
SN  - 0162-3192
N1  - 2. ISSN: 0162-3192. - 3. ISSN: 0731-5090
SP  - 66
EP  - 72
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Interplanetary Mission Analysis for Non-Perfectly Reflecting Solar Sailcraft Using Evolutionary Neurocontrol
JF  - 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)
Y1  - 2004
SN  - 0-87703-509-1
N1  - Astrodynamics Conference <2003, Big Sky, Mont.> ; American Institute of Aeronautics and Astronautics <Reston, Va.> ; AAS-03-579
SP  - 1247
EP  - 1262
PB  - Univelt
CY  - San Diego, Calif.
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Low-Thrust Trajectory Optimization and Interplanetary Mission Analysis Using Evolutionary Neurocontrol
JF  - Deutscher Luft- und Raumfahrtkongress 2004 : Dresden, 20. bis 23. September 2004, Motto: Luft- und Raumfahrt - Brücke für eine wissensbasierte Gesellschaft / Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. - Bd. 2. - (Jahrbuch ... der Deutschen Gesellschaft für Luft- und Raumfahrt)
Y1  - 2004
N1  - Deutscher Luft- und Raumfahrt-Kongress <2004, Dresden> ; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth ; DGLR-2004-116
SP  - 917
EP  - 926
CY  - Bonn
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Evolutionary Neurocontrol: A Smart Method for Global Optimization of Low-Thrust Trajectories
JF  - 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)
Y1  - 2004
N1  - American Institute of Aeronautics and Astronautics <Reston, Va.> ; AIAA/AAS Astrodynamics Specialist Conference and Exhibit <2004, Providence, RI> ; AIAA paper number: AIAA-2004-5405
PB  - American Inst. of Aeronautics and Astronautics
CY  - Reston, Va.
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Optimal Solar Sail Trajectories for Missions to the Outer Solar System
JF  - 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)
Y1  - 2004
N1  - American Institute of Aeronautics and Astronautics <Reston, Va.> ; AIAA/AAS Astrodynamics Specialist Conference and Exhibit <2004, Providence, RI> ; AIAA paper number: AIAA-2004-5406
PB  - American Inst. of Aeronautics and Astronautics
CY  - Reston, Va.
ER  - 
TY  - CHAP
A1  - Seboldt, Wolfgang
A1  - Blome, Hans-Joachim
A1  - Dachwald, Bernd
A1  - Richter, Lutz
T1  - Proposal for an integrated European space exploration strategy
T2  - 55th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law
N2  - Recently, in his vision for space exploration, US president Bush announced to extend human presence across the solar system, starting with a human return to the Moon as early as 2015 in preparation for human exploration of Mars and other destinations. In Europe, an exploration program, termed AURORA, was established by ESA in 2001 – funded on a voluntary basis by ESA member states – with a clear focus on Mars and the ultimate goal of landing humans on Mars around 2030 in international cooperation. In 2003, a Human Spaceflight Vision Group was appointed by ESA with the task to develop a vision for the role of human spaceflight during the next quarter of the century. The resulting vision focused on a European-led lunar exploration initiative as part of a multi-decade, international effort to strengthen European identity and economy. After a review of the situation in Europe concerning space exploration, the paper outlines an approach for a consistent positioning of exploration within the existing European space programs, identifies destinations, and develops corresponding scenarios for an integrated strategy, starting with robotic missions to the Moon, Mars, and near-Earth asteroids. The interests of the European planetary in-situ science community, which recently met at DLR Cologne, are considered. Potential robotic lunar missions comprise polar landings to search for frozen volatiles and a sample return. For Mars, the implementation of a modest robotic landing mission in 2009 to demonstrate the capability for landing and prepare more ambitious and complex missions is discussed. For near-Earth asteroid exploration, a low-cost in-situ technology demonstration mission could yield important results. All proposed scenarios offer excellent science and could therefore create synergies between ESA’s mandatory and optional programs in the area of planetary science and exploration. The paper intents to stimulate the European discussion on space exploration and reflects the personal view of the authors.
Y1  - 2004
N1  - 55th International Astronautical Congress 2004 - Vancouver, Canada
SP  - 1
EP  - 10
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
T1  - Solar sail performance requirements for missions to the outer solar system and beyond
T2  - 55th International Astronautical Congress 2004
N2  - 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.
Y1  - 2004
U6  - http://dx.doi.org/10.2514/6.IAC-04-S.P.11
N1  - 55th International Astronautical Congress 2004 - Vancouver, Canada
SP  - 1
EP  - 9
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Seboldt, W.
T1  - Multiple Near-Earth Asteroid Rendezvous and Sample Return Using First Generation Solar Sailcraft
JF  - Acta Astronautica. 57 (2005), H. 11
Y1  - 2005
SN  - 0094-5765
SP  - 864
EP  - 875
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Optimization of very-low-thrust trajectories using evolutionary neurocontrol
JF  - Acta Astronautica. 57 (2005), H. 2-8
Y1  - 2005
SN  - 0094-5765
SP  - 175
EP  - 185
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Optimal Solar Sail Trajectories for Missions to the Outer Solar System
JF  - Journal of guidance, control, and dynamics. 28 (2005), H. 6
Y1  - 2005
SN  - 0162-3192
N1  - 2. ISSN: 0162-3192. - 3. ISSN: 0731-5090
SP  - 1187
EP  - 1193
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
A1  - Macdonald, Malcolm
A1  - Mengali, Giovanni
A1  - Quatra, Alessandro A.
A1  - McInnes, Colin R.
A1  - Rios-Reyes, Leonel
A1  - Scheerers, Daniel J.
A1  - Wie, Bong
A1  - Görlich, Marianne
A1  - Lura, Franz
A1  - Diedrich, Benjamin
A1  - Baturkin, Volodymyr
A1  - Coverstone, Victoria L.
A1  - Leipold, Manfred
A1  - Garbe, Gregory P.
T1  - Potential Solar Sail Degradation Effects on Trajectory and Attitude Control
JF  - AIAA Guidance, Navigation and Control Conference and Exhibit - AIAA Modeling and Simulation Technologies Conference and Exhibit - AIAA Atmospheric Flight Mechanics Conference and Exhibit : [San Francisco, California, 15 - 18 August 2005 ; papers]. - (AIAA meeting papers on disc ; [10.]2005,16-17)
Y1  - 2005
SN  - 1-56347-765-3
N1  - American Institute of Aeronautics and Astronautics <Reston, Va.> ; AIAA Guidance, Navigation, and Control Conference and Exhibit <2005, San Francisco, Calif.> ; AIAA paper number: AIAA-2006-6172
Link "<a href="https://arc.aiaa.org/doi/book/10.2514/MGNC05"_blank">https://arc.aiaa.org/doi/book/10.2514/MGNC05</a>" am 15.07.2022 nachgetragen Behr
PB  - American Institute of Aeronautics and Astronautics
CY  - Reston, Va.
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Wie, Bong
T1  - Solar Sail Trajectory Optimization for Intercepting, Impacting, and Deflecting Near-Earth Asteroids
JF  - AIAA Guidance, Navigation and Control Conference and Exhibit - AIAA Modeling and Simulation Technologies Conference and Exhibit - AIAA Atmospheric Flight Mechanics Conference and Exhibit : [San Francisco, California, 15 - 18 August 2005 ; papers]. - (AIAA meeting papers on disc ; [10.]2005,16-17)
Y1  - 2005
SN  - 1-56347-765-3
N1  - American Institute of Aeronautics and Astronautics <Reston, Va.> ; AIAA Guidance, Navigation, and Control Conference and Exhibit <2005, San Francisco, Calif.> ; AIAA paper number: AIAA-2006-6176
PB  - American Institute of Aeronautics and Astronautics
CY  - Reston, Va.
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Ohndorf, A.
A1  - Seboldt, W.
T1  - Optimierung der Lageregelung von Raumfahrzeugen mit Niedrigschubantrieb mittels evolutionärer neuronaler Regler / A. Ohndorf ; B. Dachwald ; W. Seboldt
JF  - Deutscher Luft- und Raumfahrtkongress 2005 : Friedrichshafen, 26. bis 29. September 2005, Motto: Luft- und Raumfahrt - Grenzen überwinden, Horizonte erweitern / Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. Bd. 3. - (Jahrbuch ... der Deutschen Gesellschaft für Luft- und Raumfahrt
Y1  - 2005
N1  - Deutscher Luft- und Raumfahrt-Kongress <2005, Friedrichshafen> ; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth ; Dokumentnr: DGLR-2005-224
SP  - 1971
EP  - 1978
PB  - DGLR
CY  - Bonn
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Seboldt, W.
T1  - Solar Sails for Near- and Medium-Term Scientific Deep Space Missions / W. Sebolt ; B. Dachwald
JF  - In-space propulsion : edited book of proceedings of the 10-IWCP, the 10th International Workshop on Combustion and Propulsion held in Lerici, La Spezia, Italy, 21-25 September 2003 / [ed.: Luigi T. DeLuca]
Y1  - 2005
N1  - Paper 31 ; International workshop on combustion and propulsion <10, 2003, Lerici>
PB  - SP Lab, Politecnico di Milano
CY  - Milano
ER  - 
TY  - JOUR
A1  - Dittus, H.
A1  - Turyshev, S. G.
A1  - Dachwald, Bernd
A1  - Blome, Hans-Joachim
T1  - A Mission to Explore the Pioneer Anomaly
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 ; Report Number: LA-UR-05-4907 ; The Pioneer Explorer Collaboration
SP  - 3
EP  - 10
PB  - ESA Publ. Div.
CY  - Noordwijk
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  - 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  - Baturkin, Volodymyr
A1  - Coverstone, Victoria
A1  - Diedrich, Ben
A1  - Garbe, Gregory
A1  - Görlich, Marianne
A1  - Leipold, Manfred
A1  - Lura, Franz
A1  - Macdonald, Malcolm
A1  - McInnes, Colin
A1  - Mengali, Giovanni
A1  - Quarta, Alessandro
A1  - Rios-Reyes, Leonel
A1  - Scheeres, Daniel J.
A1  - Seboldt, Wolfgang
A1  - Wie, Bong
T1  - Potential effects of optical solar sail degredation on trajectory design
T2  - AAS/AIAA Astrodynamics Specialist
N2  - 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.
Y1  - 2005
N1  - 2005 AAS/AIAA Astrodynamics Specialist Conference, 7-11.08.2005. Lake Tahoe, California
https://www.space-flight.org/AAS_meetings/2005_astro/2005_astro.html
SP  - 1
EP  - 23
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
T1  - Optimization of very-low-thrust trajectories using evolutionary neurocontrol
JF  - Acta Astronautica
N2  - 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).
Y1  - 2005
SN  - 1879-2030
VL  - 57
IS  - 2-8
SP  - 175
EP  - 185
PB  - Elsevier
CY  - Amsterdam [u.a.]
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Seboldt, W.
A1  - Richter, L.
T1  - Multiple rendezvous and sample return missions to near-Earth objects using solar sailcraft / Dachwald, B. ; Seboldt, W. ; Richter, L.
JF  - Acta Astronautica. 59 (2006), H. 8-11
Y1  - 2006
SN  - 0094-5765
N1  - International Conference on Low Cost Planetary Missions <5, 2003, Noordwijk> ; Selected Proceedings
SP  - 768
EP  - 776
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Mengali, Giovanni
A1  - Quarta, Alessandrao A.
A1  - Macdonald, Malcolm
T1  - Parametric Model and Optimal Control of Solar Sails with Optical Degradation
JF  - Journal of guidance, control, and dynamics. 29 (2006), H. 5
Y1  - 2006
SN  - 0162-3192
N1  - 2. ISSN: 0731-5090
SP  - 1170
EP  - 1178
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Kahle, Ralph
A1  - Wie, Bong
T1  - Solar Sailing Kinetic Energy Impactor (KEI) Mission Design Tradeoffs for Impacting and Deflecting Asteroid 99942 Apophis
JF  - 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 )
Y1  - 2006
SN  - 1-56347-802-1
N1  - American Institute of Aeronautics and Astronautics <Reston, Va.> ; American Astronautical Society ; AIAA/AAS Astrodynamics Specialist Conference & Exhibit <2006,  Keystone, Colo.> ; AIAA paper number: AIAA-2006-6178
SP  - 1
EP  - 20
PB  - American Institute of Aeronautics and Astronautics
CY  - Reston, Va.
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Ohndorf, A.
A1  - Wie, Bong
T1  - Solar Sail Trajectory Optimization for the Solar Polar Imager (SPI) Mission
JF  - 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 )
Y1  - 2006
SN  - 1-56347-802-1
N1  - American Institute of Aeronautics and Astronautics <Reston, Va.> ; American Astronautical Society ; AIAA/AAS Astrodynamics Specialist Conference & Exhibit <2006,  Keystone, Colo.> ; AIAA paper number: AIAA-2006-6177
PB  - American Institute of Aeronautics and Astronautics
CY  - Reston, Va.
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Carnelli, I.
A1  - Vasile, M.
T1  - Low-Thrust Gravity Assist Trajectory Optimization Using Evolutionary Neurocontrollers / I. Carnelli ; B. Dachwald ; M. Vasile ...
JF  - 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)
Y1  - 2006
SN  - 0-87703-527-X
N1  - Astrodynamics Conference <2005, South Lake Tahoe, Calif.> ; American Astronautical Society ; Number: AAS-05-374
SP  - 1911
EP  - 1928
PB  - Univelt
CY  - San Diego, Calif.
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Baturkin, Volodymyr
A1  - Coverstone, Victoria L.
A1  - Dietrich, Benjamin
A1  - Garbe, Gregory P.
A1  - Görlich, Marianne
A1  - Leipold, Manfred
A1  - Lura, Franz
A1  - Macdonald, Malcolm
A1  - McInnes, Colin R.
A1  - Mengali, Giovanni
A1  - Quatra, Alessandro A.
A1  - Rios-Reyes, Leonel
A1  - Scheeres, Daniel J.
A1  - Seboldt, Wolfgang
A1  - Wie, Bong
T1  - Potential Effects of Optical Solar Sail Degradation on Interplanetary Trajectory Design
JF  - 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)
Y1  - 2006
UR  - http://www.spacesailing.net/paper/200508_LakeTahoe_Dachwald+.pdf
SN  - 0-87703-527-X
N1  - Astrodynamics Conference <2005, South Lake Tahoe, Calif.> ; American Astronautical Society ; Number: AAS-05-413
SP  - 2569
EP  - 2592
PB  - Univelt
CY  - San Diego, Calif.
ER  - 
TY  - JOUR
A1  - Leipold, M.
A1  - Fichtner, H.
A1  - Heber, B.
A1  - Groepper, P.
A1  - Lascar, S.
A1  - Burger, F.
A1  - Eiden, M.
A1  - Niederstadt, T.
A1  - Sickinger, C.
A1  - Herbeck, L.
A1  - Dachwald, Bernd
A1  - Seboldt, W.
T1  - Heliopause Explorer - A Sailcraft Mission to the Outer Boundaries of the Solar System
JF  - Acta Astronautica. 59 (2006), H. 8-11
Y1  - 2006
SN  - 0094-5765
N1  - International Conference on Low Cost Planetary Missions <5, 2003, Noordwijk> ; Selected Proceedings
SP  - 786
EP  - 796
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Carnelli, I.
A1  - Vasile, M.
T1  - Evolutionary Neurocontrol as a Novel Method for Low-Thrust Gravity Assist Trajectory Optimization / I. Carnelli ; B. Dachwald ; M. Vasile
JF  - 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]
Y1  - 2006
SN  - 4-99005-002-9
N1  - International Symposium on Space Technology and Science <25, 2006, Kanazawa> ; ISTS 2006-d-46
SP  - 569
EP  - 574
PB  - JSASS
CY  - Tokyo
ER  - 
TY  - CHAP
A1  - Loeb, Horst W.
A1  - Schartner, Karl-Heinz
A1  - Seboldt, Wolfgang
A1  - Dachwald, Bernd
A1  - Streppel, Joern
A1  - Meusemann, Hans
A1  - Schülke, Peter
T1  - SEP for a lander mission to the jovian moon europa
T2  - 57th International Astronautical Congress
N2  - Under DLR-contract, Giessen University and DLR Cologne are studying solar-electric propulsion missions (SEP) to the outer regions of the solar system. The most challenging reference mission concerns the transport of a 1.35-tons chemical lander spacecraft into an 80-RJ circular orbit around Jupiter, which would enable to place a 375 kg lander with 50 kg of scientific instruments on the surface of the icy moon "Europa". Thorough analyses show that the best solution in terms of SEP launch mass times thrusting time would be a two-stage EP module and a triple-junction solar array with concentrators which would be deployed step by step. Mission performance optimizations suggest to propel the spacecraft in the first EP stage by 6 gridded ion thrusters, running at 4.0 kV of beam voltage, which would save launch mass, and in the second stage by 4 thrusters with 1.25 to 1.5 kV of positive high voltage saving thrusting time. In this way, the launch mass of the spacecraft would be kept within 5.3 tons. Without a launcher's C3 and interplanetary gravity assists, Jupiter might be reached within about 4 yrs. The spiraling-down into the parking orbit would need another 1.8 yrs. This "large mission" can be scaled down to a smaller one, e.g., by halving all masses, the solar array power, and the number of thrusters. Due to their reliability, long lifetime and easy control, RIT-22 engines have been chosen for mission analysis. Based on precise tests, the thruster performance has been modeled.
Y1  - 2006
U6  - http://dx.doi.org/10.2514/6.IAC-06-C4.4.04
N1  - 57th International Astronautical Congress, 02 October 2006 - 06 October 2006, Valencia, Spain.
SP  - 1
EP  - 12
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Kahle, Ralph
A1  - Wie, Bong
T1  - Solar sail Kinetic Energy Impactor (KEI) mission design tradeoffs for impacting and deflecting asteroid 99942 Apophis
T2  - AIAA/AAS Astrodynamics Specialist Conference and Exhibit
N2  - 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.
KW  - Solar Sail
KW  - Asteroid Deflection
KW  - Planetary Protection
KW  - Trajectory Optimization
Y1  - 2006
U6  - http://dx.doi.org/10.2514/6.2006-6178
N1  - AIAA/AAS Astrodynamics Specialist Conference and Exhibit, 21 August 2006 - 24 August 2006, Keystone, Colorado(USA).
SP  - 1
EP  - 20
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Ohndorf, A.
T1  - 1st ACT Global Trajectory Optimisation Competition : Results found at DLR
JF  - Acta Astronautica. 61 (2007), H. 9
Y1  - 2007
SN  - 0094-5765
N1  - Global Trajectory Optimization ;  Results of the First Competition Organised by the Advanced Concept Team (ACT) of the European Space Agency (ESA)
SP  - 742
EP  - 752
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - McDonald, Malcolm
A1  - McInnes, Colin R.
A1  - Mengali, Giovanni
T1  - Impact of Optical Degradation on Solar Sail Mission Performance
JF  - Journal of Spacecraft and Rockets. 44 (2007), H. 4
Y1  - 2007
SN  - 0022-4650
N1  - 2. ISSN: 1533-6794
SP  - 740
EP  - 749
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Wi, Bong
T1  - Solar Sail Kinetic Energy Impactor Trajectory Optimization for an Asteroid-Deflection Mission
JF  - Journal of Spacecraft and Rockets. 44 (2007), H. 4
Y1  - 2007
SN  - 0022-4650
N1  - 2. ISSN: 1533-6794
SP  - 755
EP  - 764
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Mengali, Giovanni
A1  - Quarta, Alessandro A.
A1  - Circi, Christian
T1  - Refined Solar Sail Force Model with Mission Application / Giovanni Mengali ; Alessandro A. Quarta , Christian Circi ;  Bernd Dachwald
JF  - Journal of Guidance, Control, and Dynamics. 30 (2007), H. 2
Y1  - 2007
SN  - 0162-3192
N1  - 2. ISBN: 0731-5090
SP  - 512
EP  - 520
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - MacDonald, Malcolm
A1  - McInnes, Colin R.
T1  - Heliocentric Solar Sail Orbit Transfers with Locally Optimal Control Laws / Malcolm Macdonald ; Colin McInnes ; Bernd Dachwald
JF  - Journal of Spacecraft and Rockets. 44 (2007), H. 1
Y1  - 2007
SN  - 0022-4650
SP  - 273
EP  - 276
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Carnelli, I.
A1  - Vasile, M.
T1  - Optimizing low-thrust gravity assist interplanetary trajectories using evolutionary neurocontrollers / I. Carnelli ; B. Dachwald ; M. Vasile
JF  - IEEE Congress on Evolutionary Computation, 2007 : CEC 2007 ; 25 - 28 September 2007, Singapore
Y1  - 2007
SN  - 978-1-424-41339-3
N1  - ISBN 10: 1-424-41339-7 ; IEEE Congress on Evolutionary Computation <2007, Singapore> ; 	Institute of Electrical and Electronics Engineers ; Nebent: CEC 2007 ; Parallel als Online-Ausg. erschienen
SP  - 965
EP  - 972
PB  - IEEE Service Center
CY  - Piscataway, NJ
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
T1  - Low-Thrust Mission Analysis and Global Trajectory Optimization Using Evolutionary Neurocontrol: New Results
T2  - European Workshop on Space Mission Analysis ESA/ESOC, Darmstadt, Germany 10 { 12 Dec 2007
N2  - 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
Y1  - 2007
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
A1  - Loeb, Horst W.
A1  - Schartner, Karl-Heinz
T1  - A comparison of SEP and NEP for a main belt asteroid sample return mission
T2  - 7th International Symposium on Launcher Technologies, Barcelona, Spain, 02-05 April 2007
N2  - Innovative interplanetary deep space missions, like a main belt asteroid sample
return mission, require ever larger velocity increments (∆V s) and thus ever
more demanding propulsion capabilities. Providing much larger exhaust velocities than chemical high-thrust systems, electric low-thrust space-propulsion
systems can significantly enhance or even enable such high-energy missions. In
1995, a European-Russian Joint Study Group (JSG) presented a study report
on “Advanced Interplanetary Missions Using Nuclear-Electric Propulsion”
(NEP). One of the investigated reference missions was a sample return (SR)
from the main belt asteroid (19) Fortuna. The envisaged nuclear power plant,
Topaz-25, however, could not be realized and also the worldwide developments
in space reactor hardware stalled. In this paper, we investigate, whether such
a mission is also feasible using a solar electric propulsion (SEP) system and
compare our SEP results to corresponding NEP results.
Y1  - 2007
SP  - 1
EP  - 10
ER  -