@inproceedings{HorikawaAshikagaYamaguchietal.2022, author = {Horikawa, Atsushi and Ashikaga, Mitsugu and Yamaguchi, Masato and Ogino, Tomoyuki and Aoki, Shigeki and Wirsum, Manfred and Funke, Harald and Kusterer, Karsten}, title = {Combined heat and power supply demonstration of Micro-Mix Hydrogen Combustion Applied to M1A-17 Gas Turbine}, series = {Proceedings of ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition (GT2022) (Volume 3A)}, booktitle = {Proceedings of ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition (GT2022) (Volume 3A)}, publisher = {American Society of Mechanical Engineers}, address = {Fairfield}, isbn = {978-0-7918-8599-4}, doi = {10.1115/GT2022-81620}, pages = {7 Seiten}, year = {2022}, abstract = {Kawasaki Heavy Industries, Ltd. (KHI), Aachen University of Applied Sciences, and B\&B-AGEMA GmbH have investigated the potential of low NOx micro-mix (MMX) hydrogen combustion and its application to an industrial gas turbine combustor. Engine demonstration tests of a MMX combustor for the M1A-17 gas turbine with a co-generation system were conducted in the hydrogen-fueled power generation plant in Kobe City, Japan. This paper presents the results of the commissioning test and the combined heat and power (CHP) supply demonstration. In the commissioning test, grid interconnection, loading tests and load cut-off tests were successfully conducted. All measurement results satisfied the Japanese environmental regulation values. Dust and soot as well as SOx were not detected. The NOx emissions were below 84 ppmv at 15 \% O2. The noise level at the site boundary was below 60 dB. The vibration at the site boundary was below 45 dB. During the combined heat and power supply demonstration, heat and power were supplied to neighboring public facilities with the MMX combustion technology and 100 \% hydrogen fuel. The electric power output reached 1800 kW at which the NOx emissions were 72 ppmv at 15 \% O2, and 60 \%RH. Combustion instabilities were not observed. The gas turbine efficiency was improved by about 1 \% compared to a non-premixed type combustor with water injection as NOx reduction method. During a total equivalent operation time of 1040 hours, all combustor parts, the M1A-17 gas turbine as such, and the co-generation system were without any issues.}, language = {en} } @article{DachwaldSeboldtLaemmerzahl2008, author = {Dachwald, Bernd and Seboldt, Wolfgang and L{\"a}mmerzahl, W.}, title = {Solar Sail Propulsion: An Enabling Technology for Fundamental Physics Missions}, series = {Lasers, Clocks and Drag Free Control : Exploration of Relativistic Gravity in Space / by Hansj{\"o}rg Dittus ..., eds. - ( Astrophysics and Space Science Library ; 349)}, journal = {Lasers, Clocks and Drag Free Control : Exploration of Relativistic Gravity in Space / by Hansj{\"o}rg Dittus ..., eds. - ( Astrophysics and Space Science Library ; 349)}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {978-3-540-34376-9}, pages = {379 -- 398}, year = {2008}, language = {en} } @inproceedings{GierseKraemerDaabetal.2013, author = {Gierse, Andreas and Kr{\"a}mer, Stefan and Daab, Dominique J. and Hessel, Joana and Baader, Fabian and M{\"u}ller, Brigitte S. and Wagner, Tobias and Gdalewitsch, Georg and Plescher, Engelbert and Pf{\"u}tzenreuter, Lysan}, title = {Experimental in-flight modal-analysis of a sounding rocket structure}, series = {21st ESA Symposium on Rocket and Ballon related Research}, booktitle = {21st ESA Symposium on Rocket and Ballon related Research}, isbn = {9789290922858}, pages = {341 -- 346}, year = {2013}, language = {en} } @inproceedings{SeboldtDachwald2003, author = {Seboldt, Wolfgang and Dachwald, Bernd}, title = {Solar sails for near-term advanced scientific deep space missions}, series = {Proceedings of the 8th International Workshop on Combustion and Propulsion}, booktitle = {Proceedings of the 8th International Workshop on Combustion and Propulsion}, pages = {14 Seiten}, year = {2003}, abstract = {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.}, 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} } @inproceedings{DachwaldWurm2009, author = {Dachwald, Bernd and Wurm, P.}, title = {Mission analysis for an advanced solar photon thruster}, series = {60th International Astronautical Congress 2009, IAC 2009}, volume = {8}, booktitle = {60th International Astronautical Congress 2009, IAC 2009}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {978-161567908-9}, pages = {6838 -- 6851}, year = {2009}, abstract = {The so-called "compound solar sail", also known as "Solar Photon Thruster" (SPT), is a solar sail design concept, for which the two basic functions of the solar sail, namely light collection and thrust direction, are uncoupled. In this paper, we introduce a novel SPT concept, termed the Advanced Solar Photon Thruster (ASPT). This model does not suffer from the simplified assumptions that have been made for the analysis of compound solar sails in previous studies. We present the equations that describe the force, which acts on the ASPT. After a detailed design analysis, the performance of the ASPT with respect to the conventional flat solar sail (FSS) is investigated for three interplanetary mission scenarios: An Earth-Venus rendezvous, where the solar sail has to spiral towards the Sun, an Earth-Mars rendezvous, where the solar sail has to spiral away from the Sun, and an Earth-NEA rendezvous (to near-Earth asteroid 1996FG3), where a large orbital eccentricity change is required. The investigated solar sails have realistic near-term characteristic accelerations between 0.1 and 0.2mm/s2. Our results show that a SPT is not superior to the flat solar sail unless very idealistic assumptions are made.}, language = {en} } @inproceedings{ThomaFisherBraun2020, author = {Thoma, Andreas and Fisher, Alex and Braun, Carsten}, title = {Improving the px4 avoid algorithm by bio-inspired flight strategies}, series = {DLRK2020 - „Luft- und Raumfahrt - Verantwortung in allen Dimensionen"}, booktitle = {DLRK2020 - „Luft- und Raumfahrt - Verantwortung in allen Dimensionen"}, doi = {10.25967/530183}, pages = {10 Seiten}, year = {2020}, 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{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{DachwaldSeboldt2008, author = {Dachwald, Bernd and Seboldt, Wolfgang}, title = {Solar Sails — Propellantless Propulsion for Near- and Medium-Term Deep-Space Missions / W. Seboldt ; B. Dachwald}, series = {Advanced Propulsion Systems and Technologies, Today to 2020 / Claudio Bruno (ed.) ... - (Progress in Astronautics and Aeronautics Series ; 223)}, journal = {Advanced Propulsion Systems and Technologies, Today to 2020 / Claudio Bruno (ed.) ... - (Progress in Astronautics and Aeronautics Series ; 223)}, publisher = {AIAA}, address = {Reston, Va.}, isbn = {978-1-56347-929-8}, pages = {460 S.}, year = {2008}, 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{GoettenHavermannBraunetal.2020, author = {G{\"o}tten, Falk and Havermann, Marc and Braun, Carsten and Marino, Matthew and Bil, Cees}, title = {Wind-tunnel and CFD investigations of UAV landing gears and turrets - Improvements in empirical drag estimation}, series = {Aerospace Science and Technology}, volume = {107}, journal = {Aerospace Science and Technology}, number = {Art. 106306}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1270-9638}, doi = {10.1016/j.ast.2020.106306}, year = {2020}, abstract = {This paper analyzes the drag characteristics of several landing gear and turret configurations that are representative of unmanned aircraft tricycle landing gears and sensor turrets. A variety of these components were constructed via 3D-printing and analyzed in a wind-tunnel measurement campaign. Both turrets and landing gears were attached to a modular fuselage that supported both isolated components and multiple components at a time. Selected cases were numerically investigated with a Reynolds-averaged Navier-Stokes approach that showed good accuracy when compared to wind-tunnel data. The drag of main gear struts could be significantly reduced via streamlining their cross-sectional shape and keeping load carrying capabilities similar. The attachment of wheels introduced interference effects that increased strut drag moderately but significantly increased wheel drag compared to isolated cases. Very similar behavior was identified for front landing gears. The drag of an electro-optical and infrared sensor turret was found to be much higher than compared to available data of a clean hemisphere-cylinder combination. This turret drag was merely influenced by geometrical features like sensor surfaces and the rotational mechanism. The new data of this study is used to develop simple drag estimation recommendations for main and front landing gear struts and wheels as well as sensor turrets. These recommendations take geometrical considerations and interference effects into account.}, language = {en} } @inproceedings{PeloniCeriottiDachwald2015, author = {Peloni, A. and Ceriotti, M. and Dachwald, Bernd}, title = {Preliminary trajectory design of a multiple NEO rendezvous mission through solar sailing}, series = {Proceedings of the International Astronautical Congress, IAC, Vol. 8, 2014}, booktitle = {Proceedings of the International Astronautical Congress, IAC, Vol. 8, 2014}, publisher = {Curran}, address = {Red Hook, NY}, isbn = {978-1-63439-986-9}, pages = {5352 -- 5366}, year = {2015}, language = {en} } @inproceedings{KapoorBraunBoller2010, author = {Kapoor, Hrshi and Braun, Carsten and Boller, Christian}, title = {Modelling and optimisation of maintenance intervals to realize structural health monitoring applications on aircraft}, series = {Structural health monitoring 2010 : proceedings of the Fifth European Workshop on Structural Health Monitoring held at Sorrento, Naples, Italy, June 28 - July 4, 2010 ; [EWSHM]}, booktitle = {Structural health monitoring 2010 : proceedings of the Fifth European Workshop on Structural Health Monitoring held at Sorrento, Naples, Italy, June 28 - July 4, 2010 ; [EWSHM]}, editor = {Casciati, Fabio}, publisher = {DEStech Publ.}, address = {Lancaster, Pa.}, isbn = {978-1-60595-024-2}, pages = {55 -- 63}, year = {2010}, language = {en} } @article{HeinEubanksLingametal.2022, author = {Hein, Andreas M. and Eubanks, T. Marshall and Lingam, Manasvi and Hibberd, Adam and Fries, Dan and Schneider, Jean and Kervella, Pierre and Kennedy, Robert and Perakis, Nikolaos and Dachwald, Bernd}, title = {Interstellar now! Missions to explore nearby interstellar objects}, series = {Advances in Space Research}, volume = {69}, journal = {Advances in Space Research}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0273-1177}, doi = {10.1016/j.asr.2021.06.052}, pages = {402 -- 414}, year = {2022}, abstract = {The recently discovered first hyperbolic objects passing through the Solar System, 1I/'Oumuamua and 2I/Borisov, have raised the question about near term missions to Interstellar Objects. In situ spacecraft exploration of these objects will allow the direct determination of both their structure and their chemical and isotopic composition, enabling an entirely new way of studying small bodies from outside our solar system. In this paper, we map various Interstellar Object classes to mission types, demonstrating that missions to a range of Interstellar Object classes are feasible, using existing or near-term technology. We describe flyby, rendezvous and sample return missions to interstellar objects, showing various ways to explore these bodies characterizing their surface, dynamics, structure and composition. Their direct exploration will constrain their formation and history, situating them within the dynamical and chemical evolution of the Galaxy. These mission types also provide the opportunity to explore solar system bodies and perform measurements in the far outer 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{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} } @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{SchartnerLoebDachwaldetal.2009, author = {Schartner, Karl-Heinz and Loeb, H. W. and Dachwald, Bernd and Ohndorf, Andreas}, title = {Perspectives of electric propulsion for outer planetary and deep space missions}, series = {European Planetary Science Congress 2009}, booktitle = {European Planetary Science Congress 2009}, pages = {416 -- 416}, year = {2009}, abstract = {Solar-electric propulsion (SEP) is superior with respect to payload capacity, flight time and flexible launch window to the conventional interplanetary transfer method using chemical propulsion combined with gravity assists. This fact results from the large exhaust velocities of electric low-thrust propulsion and is favourable also for missions to the giant planets, Kuiper-belt objects and even for a heliopause probe (IHP) as shown in three studies by the authors funded by DLR. They dealt with a lander for Europa and a sample return mission from a mainbelt asteroid [1], with the TANDEM mission [2]; the third recent one investigates electric propulsion for the transfer to the edge of the solar system. All studies are based on triple-junction solar arrays, on rf-ion thrusters of the qualified RIT-22 type and they use the intelligent trajectory optimization program InTrance [3].}, language = {en} }