TY  - CHAP
A1  - Dachwald, Bernd
A1  - Feldmann, Marco
A1  - Espe, Clemens
A1  - Plescher, Engelbert
A1  - Konstantinidis, K.
A1  - Forstner, R.
T1  - Enceladus explorer - A maneuverable subsurface probe for autonomous navigation through deep ice
T2  - 63rd International Astronautical Congress 2012, IAC 2012; Naples; Italy; 1 October 2012 through 5 October 2012. (Proceedings of the International Astronautical Congress, IAC ; 3)
Y1  - 2012
SN  - 978-1-62276-979-7
SP  - 1756
EP  - 1766
PB  - Curran
CY  - Red Hook, NY
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Mikucki, Jill A.
A1  - Tulaczyk, Slawek
A1  - Digel, Ilya
A1  - Feldmann, Marco
A1  - Espe, Clemens
A1  - Plescher, Engelbert
A1  - Xu, Changsheng
T1  - 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
N2  - 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.
KW  - Eisschicht
KW  - Sonde
KW  - subsurface ice
KW  - subglacial aquatic ecosystems
Y1  - 2012
ER  - 
TY  - CHAP
A1  - Borggrafe, Andreas
A1  - Ohndorf, Andreas
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
T1  - Analysis of interplanetary solar sail trajectories with attitude dynamics
T2  - Dynamics and Control of Space Systems 2012
N2  - 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.
Y1  - 2012
SN  - 978-0-87703-587-9
SP  - 1553
EP  - 1569
PB  - Univelt Inc
CY  - San Diego
ER  - 
TY  - JOUR
A1  - Loeb, Horst Wolfgang
A1  - Schartner, Karl-Heinz
A1  - Dachwald, Bernd
A1  - Ohndorf, Andreas
A1  - Seboldt, Wolfgang
T1  - Interstellar heliopause probe
JF  - Труды МАИ
N2  - There is common agreement within the scientific community that in order to understand our local galactic environment it will be necessary to send a spacecraft into the region beyond the solar wind termination shock. Considering distances of 200 AU for a new mission, one needs a spacecraft traveling at a speed of close to 10 AU/yr in order to keep the mission duration in the range of less than 25 yrs, a transfer time postulated by European Space Agency (ESA). Two propulsion options for the mission have been proposed and discussed so far: the solar sail propulsion and the ballistic/radioisotope-electric propulsion (REP). As a further alternative, we here investigate a combination of solar-electric propulsion (SEP) and REP. The SEP stage consists of six 22-cms diameter RIT-22 ion thrusters working with a high specific impulse of 7377 s corresponding to a positive grid voltage of 5 kV. Solar power of 53 kW at begin of mission (BOM) is provided by a lightweight solar array.
Y1  - 2012
IS  - 60
SP  - 2
EP  - 2
PB  - Moskauer Staatliches Luftfahrtinstitut (МАИ)
CY  - Moskau
ER  - 
TY  - JOUR
A1  - Funke, Harald
A1  - Recker, E.
A1  - Bosschaerts, W.
A1  - Boonen, Q.
A1  - Börner, Sebastian
T1  - Parametrical study of the „Micromix“ hydrogen combustion principle
JF  - 10th International Symposium on Experimental and Computational Aerothermodynamics of Internal Flows, ISAIF10-049, Brussels, Belgium, 4-7 July 2011
Y1  - 2011
ER  - 
TY  - JOUR
A1  - Esch, Thomas
A1  - Funke, Harald
A1  - Roosen, Peter
A1  - Jarolimek, Ulrich
T1  - Biogenic Vehicle Fuels in General Aviation Aircrafts
JF  - MTZ worldwide. 72 (2011), H. 1
Y1  - 2011
N1  - recherchierbar für Angehörige der FH Aachen
SP  - 38
EP  - 43
PB  - Springer Automotive Media
CY  - Wiesbaden
ER  - 
TY  - JOUR
A1  - Funke, Harald
A1  - Börner, Sebastian
A1  - Falk, F.
A1  - Hendrick, P.
T1  - Control system modifications and their effects on the operation of a hydrogen-fueled Auxiliary Power Unit
JF  - XX international symposium on air breathing engines 2011 : ISABE 2011, Gothenburg, Sweden, 12-16 September, 2011. Vol. 2.
Y1  - 2011
SN  - 9781618391803
N1  - 20th International Symposium on Air Breathing Engines 2011 : (ISABE 2011) : Gothenburg, Sweden, 12-16 September, 2011.
SP  - 929
EP  - 938
PB  - American Institute of Aeronautics and Astronautics
CY  - Reston, VA
ER  - 
TY  - JOUR
A1  - Funke, Harald
A1  - Börner, Sebastian
A1  - Krebs, W.
A1  - Wolf, E.
T1  - Experimental Characterization of Low NOx Micromix Prototype Combustors for Industrial Gas Turbine Applications
JF  - ASME Turbo Expo 2011 ; Vancouver, Canada, June 6-10, 2011
Y1  - 2011
N1  - GT2011-45305
ER  - 
TY  - JOUR
A1  - Robinson, A. E.
A1  - Funke, Harald
A1  - Hendrick, P.
T1  - Design and Testing of a Micromix Combustor With Recuperative Wall Cooling for a Hydrogen Fueled µ-Scale Gas Turbine
JF  - Journal of engineering for gas turbines and power
Y1  - 2011
SN  - 1528-8919
VL  - 133
IS  - 8
PB  - ASME
CY  - New York
ER  - 
TY  - JOUR
A1  - Bühler, Yves
A1  - Christen, Marc
A1  - Kowalski, Julia
A1  - Bartelt, Perry
T1  - Sensitivity of snow avalanche simulations to digital elevation model quality and resolution
JF  - Annals of Glaciology
N2  - Digital elevation models (DEMs), represent the three-dimensional terrain and are the basic input for numerical snow avalanche dynamics simulations. DEMs can be acquired using topographic maps or remote-sensing technologies, such as photogrammetry or lidar. Depending on the acquisition technique, different spatial resolutions and qualities are achieved. However, there is a lack of studies that investigate the sensitivity of snow avalanche simulation algorithms to the quality and resolution of DEMs. Here, we perform calculations using the numerical avalance dynamics model RAMMS, varying the quality and spatial resolution of the underlying DEMs, while holding the simulation parameters constant. We study both channelized and open-terrain avalanche tracks with variable roughness. To quantify the variance of these simulations, we use well-documented large-scale avalanche events from Davos, Switzerland (winter 2007/08), and from our large-scale avalanche test site, Valĺee de la Sionne (winter 2005/06). We find that the DEM resolution and quality is critical for modeled flow paths, run-out distances, deposits, velocities and impact pressures. Although a spatial resolution of ~25 m is sufficient for large-scale avalanche modeling, the DEM datasets must be checked carefully for anomalies and artifacts before using them for dynamics calculations.
KW  - snow
KW  - avalanche
Y1  - 2011
SN  - 1727-5644
VL  - 52
IS  - 58
SP  - 72
EP  - 80
PB  - Cambridge University Press
CY  - Cambridge
ER  - 
TY  - CHAP
A1  - Olaru, Alexandra Maria
A1  - Kowalski, Julia
A1  - Sethi, Vaishali
A1  - Blümich, Bernhard
T1  - Fluid Transport in Porous Media probed by Relaxation-Exchange NMR
T2  - 2011 Fall Meeting, AGU, San Francisco, Calif., 5-9 Dec.
Y1  - 2011
N1  - H12B-07; American Geophysical Union
ER  - 
TY  - CHAP
A1  - Funke, Harald
A1  - Börner, Sebastian
A1  - Hendrick, P.
A1  - Recker, E.
T1  - Modification and testing of an engine and fuel control system for a hydrogen fuelled gas turbine
T2  - Progress in Propulsion Physics. Vol. 2
Y1  - 2011
SN  - 978-2-7598-0673-7
SP  - 475
EP  - 486
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - CHAP
A1  - Ohndorf, Andreas
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
A1  - Schartner, Karl-Heinz
T1  - Flight times to the heliopause using a combination of solar and radioisotope electric propulsion
T2  - 32nd International Electric Propulsion Conference
N2  - We investigate the interplanetary flight of a low-thrust space probe to the heliopause,located at a distance of about 200 AU from the Sun. Our goal was to reach this distance within the 25 years postulated by ESA for such a mission (which is less ambitious than the 15-year goal set by NASA). Contrary to solar sail concepts and combinations of allistic and electrically propelled flight legs, we have investigated whether the set flight time limit could also be kept with a combination of solar-electric propulsion and a second, RTG-powered upper stage. The used ion engine type was the RIT-22 for the first stage and the RIT-10 for the second stage. Trajectory optimization was carried out with the low-thrust optimization program InTrance, which implements the method of Evolutionary Neurocontrol,using Artificial Neural Networks for spacecraft steering and Evolutionary Algorithms to optimize the Neural Networks’ parameter set. Based on a parameter space study, in which the number of thrust units, the unit’s specific impulse, and the relative size of the solar power generator were varied, we have chosen one configuration as reference. The transfer time of this reference configuration was 29.6 years and the fastest one, which is technically
more challenging, still required 28.3 years. As all flight times of this parameter study were longer than 25 years, we further shortened the transfer time by applying a launcher-provided hyperbolic excess energy up to 49 km2/s2. The resulting minimal flight time for the reference configuration was then 27.8 years. The following, more precise optimization to a launch with the European Ariane 5 ECA rocket reduced the transfer time to 27.5 years. This is the fastest mission design of our study that is flexible enough to allow a launch every
year. The inclusion of a fly-by at Jupiter finally resulted in a flight time of 23.8 years,which is below the set transfer-time limit. However, compared to the 27.5-year transfer,this mission design has a significantly reduced launch window and mission flexibility if the
escape direction is restricted to the heliosphere’s “nose".
KW  - low-thrust trajectory optimization
KW  - heliosphere
KW  - ion propulsion
Y1  - 2011
N1  - IEPC-2011-051
32nd International Electric Propulsion Conference,September 11–15, 2011
Wiesbaden, Germany
SP  - 1
EP  - 12
ER  - 
TY  - JOUR
A1  - Scholz, Christina
A1  - Romagnoli, Daniele
A1  - Dachwald, Bernd
A1  - Theil, Stephan
T1  - Performance analysis of an attitude control system for solar sails using sliding masses
JF  - Advances in Space Research
Y1  - 2011
SN  - 0273-1177
VL  - 48
IS  - 11
SP  - 1822
EP  - 1835
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - CHAP
A1  - Loeb, Horst W.
A1  - Schartner, Karl-Heinz
A1  - Dachwald, Bernd
A1  - Ohndorf, Andreas
A1  - Seboldt, Wolfgang
T1  - An Interstellar – Heliopause mission using a combination of solar/radioisotope electric propulsion
T2  - Presented at the 32nd International Electric Propulsion Conference
N2  - There is common agreement within the scientific community that in order to understand our local galactic environment it will be necessary to send a spacecraft into the region beyond the solar wind termination shock. Considering distances of 200 AU for a new mission, one needs a spacecraft travelling at a speed of close to 10 AU/yr in order to keep the mission duration in the range of less than 25 yrs, a transfer time postulated by ESA.Two propulsion options for the mission have been proposed and discussed so far: the solar sail propulsion and the ballistic/radioisotope electric propulsion. As a further alternative, we here investigate a combination of solar-electric propulsion and radioisotope-electric propulsion. The solar-electric propulsion stage consists of six 22 cm diameter “RIT-22”ion thrusters working with a high specific impulse of 7377 s corresponding to a positive grid voltage of 5 kV. Solar power of 53 kW BOM is provided by a light-weight solar array. The REP-stage consists of four space-proven 10 cm diameter “RIT-10” ion thrusters that will be operating one after the other for 9 yrs in total. Four advanced radioisotope generators provide 648 W at BOM. The scientific instrument package is oriented at earlier studies. For its mass and electric power requirement 35 kg and 35 W are assessed, respectively. Optimized trajectory calculations, treated in a separate contribution, are based on our “InTrance” method.The program yields a burn out of the REP stage in a distance of 79.6 AU for a usage of 154 kg of Xe propellant. With a C3 = 45,1 (km/s)2 a heliocentric probe velocity of 10 AU/yr is reached at this distance, provided a close Jupiter gravity assist adds a velocity increment of 2.7 AU/yr. A transfer time of 23.8 yrs results for this scenario requiring about 450 kg Xe for the SEP stage, jettisoned at 3 AU. We interpret the SEP/REP propulsion as a competing alternative to solar sail and ballistic/REP propulsion. Omiting a Jupiter fly-by even allows more launch flexibility, leaving the mission duration in the range of the ESA specification.
Y1  - 2011
N1  - 32nd International Electric Propulsion Conference, 11-15 September. Wiesbaden, Germany
SP  - 1
EP  - 7
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Xu, Changsheng
A1  - Feldmann, Marco
A1  - Plescher, Engelbert
A1  - Digel, Ilya
A1  - Artmann, Gerhard
T1  - Development and testing of a subsurface probe for detection of life in deep ice : [abstract]
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).
KW  - Eisschicht
KW  - Sonde
KW  - subsurface probe
KW  - subsurface ice research
Y1  - 2011
ER  - 
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  - Thenent, N. E.
A1  - Dahmann, Peter
T1  - Increasing aircraft design flexibility ‐ The development of a hydrostatic transmission for gliders with self‐launching capability
T2  - Deutscher Luft- und Raumfahrtkongress 2011 : Bremen, 27. bis 29. September 2011 ; Tagungsband
Y1  - 2011
SN  - 978-3-9321-8274-7
SP  - 865
EP  - 883
PB  - Dt. Gesellschaft für Luft- und Raumfahrt
CY  - Bonn
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Wurm, Patrick
T1  - Mission analysis and performance comparison for an Advanced Solar Photon Thruster
JF  - Advances in Space Research
Y1  - 2011
SN  - 0273-1177
VL  - 48
IS  - 11
SP  - 1858
EP  - 1868
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - CHAP
A1  - Thenent, N. E.
A1  - Dahmann, Peter
T1  - Hydrostatic propeller drive
T2  - Proceedings of the conference : 18 - 20 May, 2011 Tampere, Finland / the Twelth Scandinavian International Conference on Fluid Power, SICFP'11. Ed.: Harri Sairiala ... Vol. 1
Y1  - 2011
SN  - 978-952-15-2517-9
SP  - 217
EP  - 227
CY  - Tampere
ER  - 
TY  - JOUR
A1  - Funke, Harald
A1  - Börner, Sebastian
A1  - Robinson, A.
A1  - Hendrick, P.
A1  - Recker, E.
T1  - Low NOx H2 combustion for industrial gas turbines of various power ranges
JF  - 5th International Gas Turbine Conference ETN-IGTC, ETN-2010-42, Brussels, Belgium, October 2010
Y1  - 2010
ER  - 
TY  - JOUR
A1  - Recker, Elmar
A1  - Bosschaerts, Walter
A1  - Wagemakers, Rolf
A1  - Hendrick, Patrick
A1  - Funke, Harald
A1  - Börner, Sebastian
T1  - Experimental study of a round jet in cross-flow at low momentum ratio
JF  - 15th International Symposium on Applications of Laser Techniques to Fluid Mechanics Lisbon, Portugal, 05-08 July, 2010 - 1
Y1  - 2010
SP  - 1
EP  - 13
ER  - 
TY  - JOUR
A1  - Funke, Harald
A1  - Robinson, A. E.
A1  - Hendrick, P.
A1  - Wagemakers, R.
T1  - Design and Testing of a Micromix Combustor With Recuperative Wall Cooling for a Hydrogen Fuelled µ-Scale Gas Turbine
JF  - Proceedings of the ASME Turbo Expo 2010 : presented at the 2010 ASME Turbo Expo, June 14 - 18, 2010, Glasgow, UK / sponsored by the International Gas Turbine Institute / Vol. 5: Industrial and cogeneration ; microturbines and small turbomachinery ; oil and gas applications ; wind turbine technology
Y1  - 2010
SN  - 978-0-7918-4400-7
N1  - GT2010-23453 ; ASME Turbo Expo ; (Glasgow) : 2010.06.14-18
SP  - 587
EP  - 596
PB  - ASME
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Börner, Sebastian
A1  - Funke, Harald
A1  - Hendrick, P.
A1  - Recker, E.
T1  - Control system modifications for a hydrogen fuelled gas-turbine
JF  - ISROMAC 13, 13th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, Honolulu, HI, US, Apr 4-7, 2010
Y1  - 2010
SN  - 978-1-617-38848-4
SP  - 665
EP  - 670
PB  - Curran
CY  - Red Hook, NY
ER  - 
TY  - JOUR
A1  - Lettini, Antonio
A1  - Havermann, Marc
A1  - Guidetti, Marco
A1  - Fornaciari, Andrea
T1  - Improved functionalities and energy saving potential on mobile machines combining electronics with flow sharing valve and variable displacement pump
JF  - IFK 7, 7th International Fluid Power Conference, Efficiency through Fluid Power, 7. Internationales Fluidtechnisches Kolloquium, Workshop Proceedings, Vol. 3, Aachen, DE, 22.-24. Mar, 2010
Y1  - 2010
SN  - 978-3-940565-92-1
N1  - IFK, 7, Internationales Fluidtechnisches Kolloquium, 7., Aachen, DE, 2010-03-22 - 2010-03-24
SP  - 103
EP  - 114
PB  - -
ER  - 
TY  - CHAP
A1  - Havermann, Marc
A1  - Seiler, F.
A1  - Henning, P.
ED  - Dillmann, Andreas
ED  - Heller, Gerd
ED  - Klaas, Michael
ED  - Kreplin, Hans-Peter
ED  - Nitsche, Wolfgang
ED  - Schröder, Wolfgang
T1  - Shock Tunnel Experiments and CFD Simulation of Lateral Jet Interaction in Hypersonic Flows
T2  - New Results in Numerical and Experimental Fluid Mechanics VII; Contributions to the 16th STAB/DGLR Symposium Aachen, Germany 2008
Y1  - 2010
SN  - 9783642142437
U6  - https://doi.org/10.1007/978-3-642-14243-7_45
N1  - Notes on numerical fluid mechanics and multidisciplinary design 112
SP  - 365
EP  - 372
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Christen, Marc
A1  - Bartelt, Perry
A1  - Kowalski, Julia
T1  - Back calculation of the In den Arelen avalanche with RAMMS: Interpretation of model results
JF  - Annals of Glaciology
N2  - Two- and three-dimensional avalanche dynamics models are being increasingly used in hazard-mitigation studies. These models can provide improved and more accurate results for hazard mapping than the simple one-dimensional models presently used in practice. However, two- and three-dimensional models generate an extensive amount of output data, making the interpretation of simulation results more difficult. To perform a simulation in three-dimensional terrain, numerical models require a digital elevation model, specification of avalanche release areas (spatial extent and volume), selection of solution methods, finding an adequate calculation resolution and, finally, the choice of friction parameters. In this paper, the importance and difficulty of correctly setting up and analysing the results of a numerical avalanche dynamics simulation is discussed. We apply the two-dimensional simulation program RAMMS to the 1968 extreme avalanche event In den Arelen. We show the effect of model input variations on simulation results and the dangers and complexities in their interpretation.
KW  - avalanche
Y1  - 2010
SN  - 1727-5644
U6  - https://doi.org/10.3189/172756410791386553
VL  - 51
IS  - 54
SP  - 161
EP  - 168
PB  - Cambridge University Press
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Christen, Marc
A1  - Kowalski, Julia
A1  - Bartelt, Perry
T1  - RAMMS: Numerical simulation of dense snow avalanches in three-dimensional terrain
JF  - Cold Regions Science and Technology
N2  - Numerical avalanche dynamics models have become an essential part of snow engineering. Coupled with field observations and historical records, they are especially helpful in understanding avalanche flow in complex terrain. However, their application poses several new challenges to avalanche engineers. A detailed understanding of the avalanche phenomena is required to construct hazard scenarios which involve the careful specification of initial conditions (release zone location and dimensions) and definition of appropriate friction parameters. The interpretation of simulation results requires an understanding of the numerical solution schemes and easy to use visualization tools. We discuss these problems by presenting the computer model RAMMS, which was specially designed by the SLF as a practical tool for avalanche engineers. RAMMS solves the depth-averaged equations governing avalanche flow with accurate second-order numerical solution schemes. The model allows the specification of multiple release zones in three-dimensional terrain. Snow cover entrainment is considered. Furthermore, two different flow rheologies can be applied: the standard Voellmy–Salm (VS) approach or a random kinetic energy (RKE) model, which accounts for the random motion and inelastic interaction between snow granules. We present the governing differential equations, highlight some of the input and output features of RAMMS and then apply the models with entrainment to simulate two well-documented avalanche events recorded at the Vallée de la Sionne test site.
KW  - RAMMS
KW  - snow
KW  - avalanche
Y1  - 2010
U6  - https://doi.org/10.1016/j.coldregions.2010.04.005
SN  - 1872-7441
VL  - 63
IS  - 1-2
SP  - 1
EP  - 14
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Blome, Hans-Joachim
A1  - Chicone, Carmen
A1  - Hehl, Friedrich W.
A1  - Mashhoon, Bahram
T1  - Nonlocal modification of Newtonian gravity
JF  - Physical Review D
Y1  - 2010
SN  - 0556-2821
N1  - 11 pages
VL  - 81
IS  - 6
SP  - 065020
ER  - 
TY  - CHAP
A1  - Borggräfe, Andreas
A1  - Dachwald, Bernd
T1  - Mission performance evaluation for solar sails using a refined SRP force model with variable optical coefficients
T2  - 2nd International Symposium on Solar Sailing
N2  - 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.
Y1  - 2010
N1  - 2nd International Symposium on Solar Sailing, ISSS 2010, 2010-07-20 - 2010-07-22. New York City College of Technology of the City University of New York, USA
SP  - 1
EP  - 6
ER  - 
TY  - CHAP
A1  - Kapoor, Hrshi
A1  - Boller, Christian
A1  - Giljohann, Sebastian
A1  - Braun, Carsten
T1  - Strategies for structural health monitoring implementation potential assessment in aircraft operational life extension considerations
T2  - 2nd International Symposium on NDT in Aerospace : November 22-24, 2010 Hamburg, Germany
Y1  - 2010
SN  - 978-3-940283-28-3
PB  - Dt. Gesellschaft für Zerstörungsfreie Prüfung
CY  - Berlin
ER  - 
TY  - CHAP
A1  - Reimer, Lars
A1  - Braun, Carsten
A1  - Wellmer, Georg
A1  - Behr, Marek
A1  - Ballmann, Josef
T1  - Development of a modular method for computational aero-structural analysis of aircraft
T2  - Summary of flow modulation and fluid-structure interaction findings. Results of the Collaborative Research Center SFB 401 at the RWTH Aachen University, Aachen, Germany, 1997-2008 / ed.: Wolfgang Schröder. Notes on numerical fluid mechanics and multidisciplinary design. Vol. 109
Y1  - 2010
SN  - 978-3-642-04087-0
SP  - 205
EP  - 238
PB  - Springer
CY  - Berlin
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
T1  - Solar sail dynamics and control
T2  - Encyclopedia of Aerospace Engineering
N2  - 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.
KW  - solar sail
KW  - sailcraft
KW  - orbital dynamics
KW  - orbit control
KW  - attitude dynamics
Y1  - 2010
U6  - https://doi.org/10.1002/9780470686652.eae292
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - CHAP
A1  - Kapoor, Hrshi
A1  - Braun, Carsten
A1  - Boller, Christian
ED  - Casciati, Fabio
T1  - Modelling and optimisation of maintenance intervals to realize structural health monitoring applications on aircraft
T2  - 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]
Y1  - 2010
SN  - 978-1-60595-024-2
SP  - 55
EP  - 63
PB  - DEStech Publ.
CY  - Lancaster, Pa.
ER  - 
TY  - JOUR
A1  - Scholz, A.
A1  - Ley, Wilfried
A1  - Dachwald, Bernd
A1  - Miau, J. J.
A1  - Juang, J. C.
T1  - Flight results of the COMPASS-1 picosatellite mission
JF  - Acta Astronautica. 67 (2010), H. 9-10
Y1  - 2010
SN  - 0094-5765
SP  - 1289
EP  - 1298
ER  - 
TY  - JOUR
A1  - Maiwald, Volker
A1  - Dachwald, Bernd
T1  - Mission Design for a Multiple-Rendezvous Mission to Jupiter's Trojans
Y1  - 2010
N1  - COSPAR 2010 ; 38th COSPAR Scientific Assembly. Held 18-25 July 2010 in Bremen, Germany [Abstract]
SP  - 3
ER  - 
TY  - JOUR
A1  - Esch, Thomas
T1  - Trends in commercial vehicle powertrains
JF  - ATZautotechnology
N2  - Low emission zones and truck bans, the rising price of diesel and increases in road tolls: all of these factors are putting serious pressure on the transport industry. Commercial vehicle manufacturers and their suppliers are in the process of identifying new solutions to these challenges as part of their efforts to meet the EEV (enhanced environmentally friendly vehicle) limits, which are currently the most robust European exhaust and emissions standards for trucks and buses.
KW  - European Transient Cycle
KW  - Common Rail Injection System
KW  - Commercial Vehicle
KW  - Selective Catalytic Reduction
KW  - Diesel Engine
Y1  - 2010
U6  - https://doi.org/10.1007/BF03247185
SN  - 2192-886X
VL  - 2010
IS  - 10
SP  - 26
EP  - 31
PB  - Vieweg & Sohn
CY  - Wiesbaden
ER  - 
TY  - RPRT
A1  - Esch, Thomas
A1  - Funke, Harald
A1  - Roosen, Petra
T1  - SIoBiA – Safety Implications of Biofuels in Aviation
N2  - Biofuels potentially interesting also for aviation purposes are predominantly liquid fuels produced from biomass. The most common biofuels today are biodiesel and bioethanol. Since diesel engines are rather rare in aviation this survey is focusing on ethanol admixed to gasoline products.
The Directive 2003/30/EC of the European Parliament and the Council of May 8th 2003 on the promotion of the use of biofuels or other renewable fuels for transport encourage a growing admixture of biogenic fuel components to fossil automotive gasoline. Some aircraft models equipped with spark ignited piston engines are approved for operation with automotive gasoline, frequently called “MOGAS” (motor gasoline). The majority of those approvals is limited to MOGAS compositions that do not contain methanol or ethanol beyond negligible amounts. In the past years (bio-)MTBE or (bio-)ETBE have been widely used as blending component of automotive gasoline whilst the usage of low-molecular alcohols like methanol or ethanol has been avoided due to the handling problems especially with regard to the strong affinity for water. With rising mandatory bio-admixtures the conversion of the basic biogenic ethanol to ETBE, causing a reduction of energetic payoff, becomes more and more unattractive. Therefore the direct ethanol admixture is accordingly favoured.
Due to the national enforcements of the directive 2003/30/EC more oxygenates produced from organic materials like bioethanol have started to appear in automotive gasolines already. The current fuel specification EN 228 already allows up to 3 % volume per volume (v/v) (bio-)methanol or up to 5 % v/v (bio-)ethanol as fuel components. This is also roughly the amount of biogenic components to comply with the legal requirements to avoid monetary penalties for producers and distributors of fuels.
Since automotive fuel is cheaper than the common aviation gasoline (AVGAS), creates less problems with lead deposits in the engine, and in general produces less pollutants it is strongly favoured by pilots. But being designed for a different set of usage scenarios the use of automotive fuel with low molecular alcohols for aircraft operation may have adverse effects in aviation operation. Increasing amounts of ethanol admixtures impose various changes in the gasoline’s chemical and physical properties, some of them rather unexpected and not within the range of flight experiences even of long-term pilots.
Y1  - 2010
N1  - Analysis of the safety implications of the use of biofuels (ethanol admixture) for piston engines and general aviation aircraft and assessment of potential environmental benefits.
PB  - EASA
CY  - Köln
ER  - 
TY  - JOUR
A1  - Robinson, A. E.
A1  - Funke, Harald
A1  - Wagemakers, R.
A1  - Grossen, J.
A1  - Bosschaerts, W.
A1  - Hendrick, P.
T1  - Numerical and Experimental Investigation of a Micromix Combustor for a Hydrogen Fuelled μ-Scale Gas Turbine
JF  - Proceedings of the ASME Turbo Expo 2009 : : presented at the 2009 ASME Turbo Expo, June 8 - 12, 2009, Orlando, Florida, USA / sponsored by the International Gas Turbine Institute
Y1  - 2009
SN  - 9780791848869
N1  - GT2009-60061
SP  - 253
EP  - 262
PB  - ASME
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Pichler, A.
A1  - George, A.
A1  - Seiler, F.
A1  - Srulijes, J.
A1  - Havermann, Marc
T1  - Doppler Picture Velocimetry (DPV) applied to hypersonics
JF  - Shock Waves [Elektronische Ressource] : 26th International Symposium on Shock Waves, Volume 1 / edited by Klaus Hannemann, Friedrich Seiler
Y1  - 2009
SN  - 978-3-540-85168-4
N1  - International Symposium on Shock Waves ; (26 ; 2007.07.15-20 ; Göttingen) ; ISSW ; (26 ; 2007.07.15-20 ; Göttingen)
SP  - 503
EP  - 508
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Fischer, Jan-Thomas
A1  - Kowalski, Julia
A1  - Pudasaini, Shiva P.
A1  - Miller, S. A.
T1  - Dynamic Avalanche Modeling in Natural Terrain
JF  - International Snow Science Workshop, Davos 2009, Proceedings ; Proc. ISSW 2009
N2  - The powerful avalanche simulation toolbox RAMMS (Rapid Mass Movements) is based on a depth-averaged
hydrodynamic system of equations with a Voellmy-Salm friction relation. The two empirical friction parameters
μ and �  correspond to a dry Coulomb friction and a viscous resistance, respectively. Although μ and � lack a
proper physical explanation, 60 years of acquired avalanche data in the Swiss Alps made a systematic calibration
possible. RAMMS can therefore successfully model avalanche flow depth, velocities, impact pressure and run
out distances. Pudasaini and Hutter (2003) have proposed extended, rigorously derived model equations that
account for local curvature and twist. A coordinate transformation into a reference system, applied to the actual
mountain topography of the natural avalanche path, is performed. The local curvature and the twist of the
avalanche path induce an additional term in the overburden pressure. This leads to a modification of the Coulomb
friction, the free-surface pressure gradient, the pressure induced by the channel, and the gravity components
along and normal to the curved and twisted reference surface. This eventually guides the flow dynamics and
deposits of avalanches. In the present study, we investigate the influence of curvature on avalanche flow in
real mountain terrain. Simulations of real avalanche paths are performed and compared for the different models
approaches. An algorithm to calculate curvature in real terrain is introduced in RAMMS. This leads to a curvature
dependent friction relation in an extended version of the Voellmy-Salm model equations. Our analysis provides
yet another step in interpreting the physical meaning and significance of the friction parameters used in the
RAMMS computational environment.
KW  - snow
KW  - avalanche
Y1  - 2009
SP  - 448
EP  - 452
ER  - 
TY  - CHAP
A1  - Börner, Sebastian
A1  - Funke, Harald
A1  - Hendrick, P.
A1  - Recker, E.
T1  - LES of Jets In Cross-Flow and Application to the “Micromix” Hydrogen Combustion
T2  - XIX International Symposium on Air Breathing Engines 2009 (ISABE 2009) : Proceedings of a meeting held 7-11 September 2009, Montreal, Canada
Y1  - 2009
SN  - 9781615676064
SP  - 1555
EP  - 1561
ER  - 
TY  - BOOK
A1  - Ley, Wilfried
A1  - Wittmann, Klaus
A1  - Hallmann, Willi
T1  - Handbook of space technology
Y1  - 2009
SN  - 978-0-470-69739-9
PB  - Wiley
CY  - Chichester
ER  - 
TY  - JOUR
A1  - Wilson, T. L.
A1  - Blome, Hans-Joachim
T1  - The Pioneer anomaly and a rotating Gödel universe
JF  - Advances in Space Research
Y1  - 2009
SN  - 0273-1177
VL  - 44
IS  - 11
SP  - 1345
EP  - 1353
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Ohndorf, Andreas
A1  - Spurmann, J.
A1  - Loeb, H. W.
A1  - Schartner, Karl-Heinz
A1  - Seboldt, Wolfgang
T1  - Mission design for a SEP mission to saturn
T2  - 60th International Astronautical Congress 2009 (IAC 2009)
N2  - Within ESA's Cosmic Vision 2015-2025 plan, a mission to explore the Saturnian System, with special emphasis on its two moons Titan and Enceladus, was selected for study, termed TANDEM (Titan and Enceladus Mission). In this paper, we describe an optimized mission design for a TANDEM-derived solar electric propulsion (SEP) mission. We have chosen the SEP mission scenario for the interplanetary transfer of the TANDEM spacecraft because all feasible gravity assist sequences for a chemical transfer between 2015 and 2025 result in long flight times of about nine years. Our SEP system is based on the German RIT ion engine. For our optimized mission design, we have extensively explored the SEP parameter space (specific impulse, thrust level, power level) and have calculated an optimal interplanetary trajectory for each setting. In contrast to the original TANDEM mission concept, which intends to use two launch vehicles and an all-chemical transfer, our SEP mission design requires only a single Ariane 5 ECA launch for the same payload mass. Without gravity assist, it yields a faster and more flexible transfer with a fight time of less than seven years, and an increased payload ratio. Our mission design proves thereby the capability of SEP even for missions into the outer solar system.
Y1  - 2009
SN  - 978-1-61567-908-9
N1  - 12-16 October 2009, Daejeon, Republic of Korea.
PB  - Curran Associates, Inc.
CY  - Red Hook, NY
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Wurm, P.
T1  - Design concept and modeling of an advanced solar photon thruster
T2  - Advances in the Astronautical Sciences
N2  - The so-called "compound solar sail", also known as "Solar Photon Thruster" (SPT), holds the potential of providing significant performance advantages over the flat solar sail. Previous SPT design concepts, however, do not consider shadowing effects and multiple reflections of highly concentrated solar radiation that would inevitably destroy the gossamer sail film. In this paper, we propose a novel advanced SPT (ASPT) design concept that does not suffer from these oversimplifications. We present the equations that describe the thrust force acting on such a sail system and compare its performance with respect to the conventional flat solar sail.
KW  - solar sails
Y1  - 2009
SN  - 978-087703554-1
SN  - 00653438
N1  - 19th AAS/AIAA Space Flight Mechanics Meeting; Savannah, GA; United States; 8 February 2009 through 12 February 2009
SP  - 723
EP  - 740
PB  - American Astronautical Society
CY  - San Diego, Calif.
ER  - 
TY  - CHAP
A1  - Reimer, Lars
A1  - Wellmer, Georg
A1  - Braun, Carsten
A1  - Ballmann, Josef
T1  - Computational methods for aero-structural analysis and optimisation of aircrafts based on reduced-order structural models
T2  - MEGADESIGN and MegaOpt - German initiatives for aerodynamic simulation and optimization in aircraft design. Results of the closing symposium of the MEGADESIGN and MegaOpt projects, Braunschweig, Germany, 23 - 24 May, 2007 / Norbert Kroll ... (Eds.) Notes on numerical fluid mechanics and multidisciplinary design. Vol. 107
N2  - In this part of the MEGADESIGN project, aeroelastic effects are introduced into the aerodynamic analysis of aircrafts by coupling DLR’s flow solvers TAU and FLOWer to a Timoshenko-beam solver. The emerging aeroelastic solvers and a method for the automatic identification of Timoshenko-beam models for wing-box structures were integrated into a simulation environment enabling the combined optimisation of aerodynamic wing shape and structure.
Y1  - 2009
SN  - 978-3-642-04092-4
SP  - 135
EP  - 150
PB  - Springer
CY  - Berlin
ER  - 
TY  - CHAP
A1  - Spurmann, Jörn
A1  - Ohndorf, Andreas
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
A1  - Löb, Horst
A1  - Schartner, Karl-Heinz
T1  - Interplanetary trajectory optimization for a sep mission to Saturn
T2  - 60th International Astronautical Congress 2009
N2  - The recently proposed NASA and ESA missions to Saturn and Jupiter pose difficult tasks to mission designers because chemical propulsion scenarios are not capable of transferring heavy spacecraft into the outer solar system without the use of gravity assists. Thus our developed mission scenario based on the joint NASA/ESA Titan Saturn System Mission baselines solar electric propulsion to improve mission flexibility and transfer time. For the calculation of near-globally optimal low-thrust trajectories, we have used a method called Evolutionary Neurocontrol, which is implemented in the low-thrust trajectory optimization software InTrance. The studied solar electric propulsion scenario covers trajectory optimization of the interplanetary transfer including variations of the spacecraft's thrust level, the thrust unit's specific impulse and the solar power generator power level. Additionally developed software extensions enabled trajectory optimization with launcher-provided hyperbolic excess energy, a complex solar power generator model and a variable specific impulse ion engine model. For the investigated mission scenario, Evolutionary Neurocontrol yields good optimization results, which also hold valid for the more elaborate spacecraft models. Compared to Cassini/Huygens, the best found solutions have faster transfer times and a higher mission flexibility in general.
KW  - Spacecraft
KW  - Reusable Rocket Engines
KW  - Hybrid Propellants
Y1  - 2009
SN  - 9781615679089
N1  - 60th International Astronautical Congress 2009 (IAC 2009)
Held 12-16 October 2009, Daejeon, Republic of Korea.
SP  - 5234
EP  - 5248
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Ohndorf, A.
A1  - Gill, E.
T1  - Optimization of low-thrust Earth-Moon transfers using evolutionary neurocontrol  / Ohndorf, A. ; Dachwald, B. ; Gill, E.
JF  - IEEE Congress on Evolutionary Computation, 2009. CEC '09.
Y1  - 2009
SN  - 978-1-4244-2958-5
SP  - 358
EP  - 364
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Wurm, P.
T1  - Mission analysis for an advanced solar photon thruster
T2  - 60th International Astronautical Congress 2009, IAC 2009
N2  - 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.
KW  - Interplanetary flight
Y1  - 2009
SN  - 978-161567908-9
N1  - 60th International Astronautical Congress 2009, IAC 2009; Daejeon; South Korea; 12 October 2009 through 16 October 2009
VL  - 8
SP  - 6838
EP  - 6851
PB  - Elsevier
CY  - Amsterdam
ER  -