TY  - CHAP
A1  - Dachwald, Bernd
A1  - Xu, Changsheng
A1  - Feldmann, Marco
A1  - Plescher, Engelbert
T1  - IceMole : Development of a novel subsurface ice probe and testing of the first prototype on the Morteratsch Glacier
T2  - EGU General Assembly 2011 Vienna | Austria | 03 – 08 April 2011
N2  - We present the novel concept of a combined drilling and melting probe for subsurface ice research. This probe, named “IceMole”, is currently developed, built, and tested at the FH Aachen University of Applied Sciences’ Astronautical Laboratory. Here, we describe its first prototype design and report the results of its field tests on the Swiss Morteratsch glacier. Although the IceMole design is currently adapted to terrestrial glaciers and ice shields, it may later be modified for the subsurface in-situ investigation of extraterrestrial ice, e.g., on Mars, Europa, and Enceladus. If life exists on those bodies, it may be present in the ice (as life can also be found in the deep ice of Earth).
Y1  - 2011
ER  - 
TY  - CHAP
A1  - 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  - Carzana, Livio
A1  - Dachwald, Bernd
A1  - Noomen, Ron
T1  - Model and trajectory optimization for an ideal laser-enhanced solar sail
T2  - 68th International Astronautical Congress
N2  - 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
Y1  - 2017
N1  - 68th International Astronautical Congress: Unlocking Imagination, Fostering Innovation and Strengthening Security, IAC 2017, 2017-09-25 → 2017-09-29, Adelaide, Australia
ER  - 
TY  - CHAP
A1  - Grundmann, Jan Thimo
A1  - Bauer, Waldemar
A1  - Biele, Jens
A1  - Boden, Ralf
A1  - Ceriotti, Matteo
A1  - Cordero, Federico
A1  - Dachwald, Bernd
A1  - Dumont, Etienne
A1  - Grimm, Christian
A1  - Herčík, David
A1  - Herique, Alain
A1  - Ho, Tra-Mi
A1  - Jahnke, Rico
A1  - Koch, Aaron
A1  - Kofman, Wlodek
A1  - Koncz, Alexander
A1  - Krause, Christian
A1  - Lange, Caroline
A1  - Lichtenheldt, Roy
A1  - Maiwald, Volker
A1  - Mikschl, Tobias
A1  - Mikulz, Eugen
A1  - Montenegro, Sergio
A1  - Pelivan, Ivanka
A1  - Peloni, Alessandro
A1  - Plettemeier, Dirk
A1  - Quantius, Dominik
A1  - Reershemius, Siebo
A1  - Renger, Thomas
A1  - Riemann, Johannes
A1  - Ruffer, Michael
A1  - Sasaki, Kaname
A1  - Schmitz, Nicole
A1  - Seboldt, Wolfgang
A1  - Seefeldt, Patric
A1  - Spietz, Peter
A1  - Spröwitz, Tom
A1  - Sznajder, Maciej
A1  - Tardivel, Simon
A1  - Toth, Norbert
A1  - Wejmo, Elisabet
A1  - Wolff, Friederike
A1  - Ziach, Christian
T1  - Efficient massively parallel prospection for ISRU by multiple near-earth asteroid rendezvous using near-term solar sails and'now-term'small spacecraft solutions
T2  - 2nd Asteroid Science Intersections with In-Space Mine Engineering – ASIME 2018
N2  - Physical interaction with small solar system bodies (SSSB) is key for in-situ resource utilization (ISRU). The design of mining missions requires good understanding of SSSB properties, including composition, surface and interior structure, and thermal environment. But as the saying goes "If you've seen one asteroid, you've seen one Asteroid": Although some patterns may begin to appear, a stable and reliable scheme of SSSB classification still has to be evolved. Identified commonalities would enable generic ISRU technology and spacecraft design approaches with a high degree of re-use. Strategic approaches require much broader in-depth characterization of the SSSB populations of interest to the ISRU community. The DLR-ESTEC GOSSAMER Roadmap Science Working Groups identified target-flexible Multiple Near-Earth asteroid (NEA) Rendezvous (MNR) as one of the missions only feasible with solar sail propulsion, showed the ability to access any inclination and a wide range of heliocentric distances as well as continuous operation close to Earth's orbit where low delta-v objects reside.
Y1  - 2018
N1  - 2nd Asteroid Science Intersections with In-Space Mine Engineering – ASIME 2018
16-17 April 2018, Belval, Luxembourg
SP  - 1
EP  - 33
ER  - 
TY  - CHAP
A1  - Jean-Pierre P., de Vera
A1  - Baque, Mickael
A1  - Billi, Daniela
A1  - Böttger, Ute
A1  - Bulat, Sergey
A1  - Czupalla, Markus
A1  - Dachwald, Bernd
A1  - de la Torre, Rosa
A1  - Elsaesser, Andreas
A1  - Foucher, Frédéric
A1  - Korsitzky, Hartmut
A1  - Kozyrovska, Natalia
A1  - Läufer, Andreas
A1  - Moeller, Ralf
A1  - Olsson-Francis, Karen
A1  - Onofri, Silvano
A1  - Sommer, Stefan
A1  - Wagner, Dirk
A1  - Westall, Frances
T1  - The search for life on Mars and in the Solar System - strategies, logistics and infrastructures
T2  - 69th International Astronautical Congress (IAC)
N2  - The question "Are we alone in the Universe?" is perhaps the most fundamental one that affects mankind. How can we address the search for life in our Solar System? Mars, Enceladus and Europa are the focus of the search for life outside the terrestrial biosphere. While it is more likely to find remnants of life (fossils of extinct life) on Mars because of its past short time window of the surface habitability, it is probably more likely to find traces of extant life on the icy moons and ocean worlds of Jupiter and Saturn. Nevertheless, even on Mars there could still be a chance to find extant life in niches near to the surface or in just discovered subglacial lakes beneath the South Pole ice cap. Here, the different approaches for the detection of traces of life in the form of biosignatures including pre-biotic molecules will be presented. We will outline the required infrastructure for this enterprise and give examples of future mission concepts to investigate the presence of life on other planets and moons. Finally, we will provide suggestions on methods, techniques, operations and strategies for preparation and realization of future life detection missions.
KW  - life detection
KW  - Mars
KW  - icy moons
KW  - habitability
KW  - space missions
Y1  - 2018
N1  - 69th International Astronautical Congress (IAC), Bremen, Germany, 1-5 October 2018.
SP  - 1
EP  - 8
ER  - 
TY  - CHAP
A1  - Grundmann, Jan Thimo
A1  - Borella, Laura
A1  - Ceriotti, Matteo
A1  - Chand, Suditi
A1  - Cordero, Federico
A1  - Dachwald, Bernd
A1  - Fexer, Sebastian
A1  - Grimm, Christian D.
A1  - Hendrikse, Jeffrey
A1  - Herčík, David
A1  - Herique, Alain
A1  - Hillebrandt, Martin
A1  - Ho, Tra-Mi
A1  - Kesseler, Lars
A1  - Laabs, Martin
A1  - Lange, Caroline
A1  - Lange, Michael
A1  - Lichtenheldt, Roy
A1  - McInnes, Colin R.
A1  - Moore, Iain
A1  - Peloni, Alessandro
A1  - Plettenmeier, Dirk
A1  - Quantius, Dominik
A1  - Seefeldt, Patric
A1  - Venditti, Flaviane c. F.
A1  - Vergaaij, Merel
A1  - Viavattene, Giulia
A1  - Virkki, Anne K.
A1  - Zander, Martin
T1  - More bucks for the bang: new space solutions, impact tourism and one unique science & engineering opportunity at T-6 months and counting
T2  - 7th IAA Planetary Defense Conference
N2  - For now, the Planetary Defense Conference Exercise 2021's incoming fictitious(!), asteroid, 2021 PDC, seems headed for impact on October 20th, 2021, exactly 6 months after its discovery. Today (April 26th, 2021), the impact probability is 5%, in a steep rise from 1 in 2500 upon discovery six days ago. We all know how these things end. Or do we? Unless somebody kicked off another headline-grabbing media scare or wants to keep civil defense very idle very soon, chances are that it will hit (note: this is an exercise!). Taking stock, it is barely 6 months to impact, a steadily rising likelihood that it will actually happen, and a huge uncertainty of possible impact energies: First estimates range from 1.2 MtTNT to 13 GtTNT, and this is not even the worst-worst case: a 700 m diameter massive NiFe asteroid (covered by a thin veneer of Ryugu-black rubble to match size and brightness), would come in at 70 GtTNT. In down to Earth terms, this could be all between smashing fireworks over some remote area of the globe and a 7.5 km crater downtown somewhere. Considering the deliberate and sedate ways of development of interplanetary missions it seems we can only stand and stare until we know well enough where to tell people to pack up all that can be moved at all and save themselves. But then, it could just as well be a smaller bright rock. The best estimate is 120 m diameter from optical observation alone, by 13% standard albedo. NASA's upcoming DART mission to binary asteroid (65803) Didymos is designed to hit such a small target, its moonlet Dimorphos. The Deep Impact mission's impactor in 2005 successfully guided itself to the brightest spot on comet 9P/Tempel 1, a relatively small feature on the 6 km nucleus. And 'space' has changed: By the end of this decade, one satellite communication network plans to have launched over 11000 satellites at a pace of 60 per launch every other week. This level of series production is comparable in numbers to the most prolific commercial airliners. Launch vehicle production has not simply increased correspondingly – they can be reused, although in a trade for performance. Optical and radio astronomy as well as planetary radar have made great strides in the past decade, and so has the design and production capability for everyday 'high-tech' products. 60 years ago, spaceflight was invented from scratch within two years, and there are recent examples of fast-paced space projects as well as a drive towards 'responsive space'. It seems it is not quite yet time to abandon all hope. We present what could be done and what is too close to call once thinking is shoved out of the box by a clear and present danger, to show where a little more preparedness or routine would come in handy – or become decisive. And if we fail, let's stand and stare safely and well instrumented anywhere on Earth together in the greatest adventure of science.
Y1  - 2021
N1  - 7th IAA Planetary Defense Conference, Vienna, Austria, 26-30 April 2021
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  - 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  - 
TY  - CHAP
A1  - Duprat, J.
A1  - Dachwald, Bernd
A1  - Hilchenbach, M.
A1  - Engrand, Cecile
A1  - Espe, C.
A1  - Feldmann, M.
A1  - Francke, G.
A1  - Görög, Mark
A1  - Lüsing, N.
A1  - Langenhorst, Falko
T1  - The MARVIN project: a micrometeorite harvester in Antarctic snow
T2  - 44th Lunar and Planetary Science Conference
N2  - MARVIN is an automated drilling and melting probe dedicated to collect pristine interplanetary dust particles (micrometeorites) from central Antarctica snow.
Y1  - 2013
N1  - 44th Lunar and Planetary Science Conference, March 18-22, 2013, The Woodlands, Texas
ER  - 
TY  - CHAP
A1  - Hallmann, Marcus
A1  - Heidecker, Ansgar
A1  - Schlotterer, Markus
A1  - Dachwald, Bernd
T1  - GTOC8: results and methods of team 15 DLR
T2  - 26th AAS/AIAA Space Flight Mechanics Meeting, Napa, CA
N2  - This paper describes the results and methods used during the 8th Global Trajectory Optimization Competition (GTOC) of the DLR team. Trajectory optimization is crucial for most of the space missions and usually can be formulated as a global optimization problem. A lot of research has been done to different type of mission problems. The most demanding ones are low thrust transfers with e.g. gravity assist sequences. In that case the optimal control problem is combined with an integer problem. In most of the GTOCs we apply a filtering of the problem based on domain knowledge.
Y1  - 2016
N1  - 26th AAS/AIAA Space Flight Mechanics Meeting, February 14-18, 2016, Napa, California, U.S.A. Napa, CA
ER  -