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  • 1.
    Abudayyeh, H.A.
    et al.
    Department of Physics, Al-Quds University, Jerusalem.
    Barghouthi, I.A.
    Department of Physics, Al-Quds University, Jerusalem.
    Slapak, Rikard
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Nilsson, Hans
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Centrifugal acceleration at high altitudes above the polar cap: A Monte Carlo simulation2015Inngår i: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 120, nr 8, 6409-6426 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A Monte Carlo simulation was used to study the outflow of O+ and H+ ions along three flight trajectories above the polar cap up to altitudes of about 15 RE. Barghouthi (2008) developed a model on the basis of altitude and velocity-dependent wave-particle interactions and a radial geomagnetic field which includes the effects of ambipolar electric field and gravitational and mirror forces. In the present work we improve this model to include the effect of the centrifugal force, with the use of relevant boundary conditions. In addition, the magnetic field and flight trajectories, namely, the central polar cap (CPC), nightside polar cap (NPC), and cusp, were calculated using the Tsyganenko T96 model. To simulate wave-particle interactions, the perpendicular velocity diffusion coefficients for O+ ions in each region were determined such that the simulation results fit the observations. For H+ ions, a constant perpendicular velocity diffusion coefficient was assumed for all altitudes in all regions as recommended by Nilsson et al. (2013). The effect of centrifugal acceleration was simulated by considering three values for the ionospheric electric field: 0 (no centrifugal acceleration), 50, and 100 mV/m. It was found that the centrifugal acceleration increases the parallel bulk velocity and decreases the parallel and perpendicular temperatures of both ion species at altitudes above about 4 RE. Centrifugal acceleration also increases the temperature anisotropy at high altitudes. At a given altitude, centrifugal acceleration decreases the density of H+ ions while it increases the density of O+ ions. This implies that with higher centrifugal acceleration more O+ ions overcome the potential barrier. It was also found that aside from two exceptions centrifugal acceleration has the same effect on the velocities of both ions. This implies that the centrifugal acceleration is universal for all particles. The parallel bulk velocities at a given value of ionospheric electric field were highest in the cusp followed by the CPC followed by the NPC. In this study a region of no wave-particle interaction was assumed in the CPC and NPC between 3.7 and 7.5 RE. In this region the perpendicular temperature was found to decrease with altitude due to perpendicular adiabatic cooling.

  • 2.
    Aevan, Nadjib Danial
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    MDO Framework for Design of Human PoweredPropellers using Multi-Objective Genetic Algorithm2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis showcases the challenges, downsides and advantages to building a MultiDisciplinary Optimization (MDO) framework to automate the generation of an efficientpropeller design built for lightly loaded operation, more specifically for humanpowered aircrafts. Two years ago, a human powered aircraft project was initiatedat Linköping University. With the help of several courses, various students performedconceptional design, calculated and finally manufactured a propeller bymeans of various materials and manufacturing techniques. The performance ofthe current propeller is utilized for benchmarking and comparing results obtainedby the MDO process.The developed MDO framework is constructed as a modeFRONITER project wereseveral Computer Aided Engineering softwares (CAE) such as MATLAB, CATIAand XFOIL are connected to perform multiple consequent optimization subprocesses.The user is presented with several design constraints such as blade quantity,required input power, segment-wise airfoil thickness, desired lift coefficientetc. Also, 6 global search optimization algorithms are investigated to determinethe one which generate most efficient result according to several set standards.The optimization process is thereafter initialized by identifying the most efficientchord distribution with a help of an initial blade cross-section which has been previouslyused in other human powered propellers, the findings are thereafter usedto determine the flow conditions at different propeller stations. Two different aerodynamicoptimized shapes are generated with the help of consecutively performedsubprocesses. The optimized propeller requires 7.5 W less input power to generatenearly equivalent thrust as the original propeller with a total efficiency exceedingthe 90 % mark (90.25 %). Moreover, the MDO framework include an automationprocess to generate a CAD design of the optimized propeller. The generatedCAD file illustrates a individual surface blade decrease of 12.5 % compared tothe original design, the lightweight design and lower input power yield an overallpropulsion system which is less tedious to operate.

  • 3. Agarwal, Anurag
    et al.
    Dowling, Ann P.
    Shin, Ho-Chul
    Graham, Will
    Sefi, Sandy
    KTH, Skolan för datavetenskap och kommunikation (CSC), Numerisk Analys och Datalogi, NADA.
    Ray-tracing approach to calculate acoustic shielding by a flying wing airframe2007Inngår i: AIAA Journal, ISSN 0001-1452, E-ISSN 1533-385X, Vol. 45, nr 5, 1080-1090 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The "silent aircraft" is in the form of a flying wing with a large wing planform and a propulsion system that is embedded in the rear of the airframe with intakes on the upper surface of the wing. Thus a large part of the forward-propagating noise from the intake ducts is expected to be shielded from observers on the ground by the wing. Acoustic shielding effects can be calculated by solving an external acoustic scattering problem for a moving aircraft. In this paper, acoustic shielding effects of the silent aircraft airframe are quantified by a ray-tracing method. The dominant frequencies from the noise spectrum of the engines are sufficiently high for ray theory to yield accurate results. It is shown that, for low-Mach number homentropic flows, a condition satisfied approximately during takeoff and approach, the acoustic rays propagate in straight lines. Thus, from Fermat's principle it is clear that classical geometrical optics and geometrical theory of diffraction solutions are applicable to this moving-body problem as well. The total amount of acoustic shielding at an observer located in the shadow region is calculated by adding the contributions from all the diffracted rays (edge-diffracted and creeping rays) and then subtrading the result from the incident field without the airframe. The three-dimensional ray-tracing solver is validated by comparing the numerical solutions with analytical high-frequency asymptotic solutions for canonical shapes. Experiments on a model-scale geometry have been conducted in an anechoic chamber to test the applicability of the ray-tracing technique. The results confirm the accuracy of the approach, which is then applied to a CAD representation of a prototype silent aircraft design. As expected, the flying wing configuration provides very significant ground shielding (in excess of 10 dB at all locations) of a source above the airframe.

  • 4.
    Aghaali, Habib
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Förbränningsmotorteknik.
    Ångström, Hans-Erik
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Förbränningsmotorteknik.
    Turbocharged SI-Engine Simulation with Cold and Hot-Measured Turbocharger Performance Maps2012Inngår i: Proceedings of ASME Turbo Expo 2012, Vol 5, ASME Press, 2012, 671-679 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Heat transfer within the turbocharger is an issue in engine simulation based on zero and one-dimensional gas dynamics. Turbocharged engine simulation is often done without taking into account the heat transfer in the turbocharger. In the simulation, using multipliers is the common way of adjusting turbocharger speed and parameters downstream of the compressor and upstream of the turbine. However, they do not represent the physical reality. The multipliers change the maps and need often to be different for different load points. The aim of this paper is to simulate a turbocharged engine and also consider heat transfer in the turbocharger. To be able to consider heat transfer in the turbine and compressor, heat is transferred from the turbine volute and into the compressor scroll. Additionally, the engine simulation was done by using two different turbocharger performance maps of a turbocharger measured under cold and hot conditions. The turbine inlet temperatures were 100 and 600°C, respectively. The turbocharged engine experiment was performed on a water-oil-cooled turbocharger (closed waste-gate), which was installed on a 2-liter gasoline direct-injected engine with variable valve timing, for different load points of the engine. In the work described in this paper, the difference between cold and hot-measured turbocharger performance maps is discussed and the quantified heat transfers from the turbine and to/from the compressor are interpreted and related to the maps.

  • 5. Ahlgren, Niklas
    et al.
    Karlsson, Thomas
    Larsson, Robin
    Spacecraft Department, OHB Sweden, Sweden.
    Noteborn, Ron
    PRISMA Mission Extension: Adapting Mission Operations to New and Changing Mission Objectives2012Inngår i: SpaceOps 2012 Conference, American Institute of Aeronautics and Astronautics, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The PRISMA in-orbit test-bed was launched in June 2010 to demonstrate strategies and technologies for formation flying and rendezvous. OHB Sweden is the prime contractor for the project which is funded by the Swedish National Space Board (SNSB) with support from DLR, CNES, and DTU. In early September of 2011, 15 months after launch, all primary mission objectives of the PRISMA formation flying satellites had been achieved and mission success was declared. Since a significant amount of delta-V capability still remained an open call for new experiments was issued, inviting both old and new experimenters to use the capabilities of the formation. Several interested parties took the opportunity to perform their own experiments with an existing platform, each coming with new mission objectives not previously planned to be flown on the PRISMA satellites. Some of these experiments were close to what had already been achieved within the nominal mission, but some included new ways of using the formation not envisioned by the spacecraft designers. The new experiments span from data collection in specific relative orbits, with a separation from a few meters to several kilometers, to entirely new modules within the on-board software. Changing from a pre-planned technology demonstration mission to operating a commercial resource required adaptation of the original operational concept, taking into account the different levels of experience of the customers and managing the satellites between experiments. This paper describes how these new mission objectives were integrated in operations and how a sometimes very short turn-around between initial concept and experiment execution was implemented with the aid of well established validation processes, high degrees of on-board autonomy and a flexible operations team.

  • 6.
    Ahluwalia, Arvind
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Computer Controlled Direct Descent2017Independent thesis Basic level (degree of Bachelor), 180 hpOppgave
    Abstract [en]

    How an aircraft performs its approach and descent towards an airport today has got big potential for improvements. It's mainly the environmental impact and safety that can, and must, be improved for a sustainable future in aviation. "Green Approaches" is a small, yet relatively well-known, optimized approach system mainly used by Scandinavian Airlines on Arlanda airport. Unfortunately "Green Approaches" aren't used often enough, due to the simple reason that it doesn't work very well during heavy traffic. Luckily further research is being done in this field to further optimize an aircraft’s approach. As of today, the most forward going research is being done by the FAA and NASA, and their new system is called NextGen OPD. The system is not fully developed yet but their goals are, as previously mentioned, to optimize today's aircraft approach. In this report the focus will also be set on improving aircraft approaches, although not by optimizing today’s system like the FAA and NASA. Instead, a whole new concept of how aircraft approach airports will be developed. The reason that a brand new concept will be developed is simple, optimizing today's aging system will not be sustainable for the future. Also, optimizing an aging system has its limits. By designing a whole new concept, a steady ground will be laid and it shall be sustainable for the coming century's technology. The new concept will be called ”C.C.D.D.”, Computer Controlled Direct Descent, and will have a lot of goals and expectations to fulfill. As hinted in the name, the new concept is built on the idea that a computer will be controlling the whole approach, and therefore the "Human factor" will more or less be eliminated. Although the main purpose of a new approach system is to decrease the negative environmental impact, by decreasing the fuel consumption during the approach. The new concept will also decrease the noise an aircraft makes during the descent and increase the possibility for a greater traffic flow in the airport’s airspace. The end result will be a "win-win" for everyone involved. An environmentally friendly aircraft approach is necessary for a sustainable future in aviation. C.C.D.D. is a system that will pay for itself with time, because of the decreased fuel consumption for airliners. The system also has the ability to be expanded to computer control departing aircrafts, due to the systems highly computerized structure and integration with airplanes autopilot.

  • 7.
    Ahlén, Kritsoffer
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Rosén, Malin
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Simulering som konstruktionsstöd2013Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
  • 8.
    Ahmad, Mustafa
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Boukli, Tarék
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Continuing Airworthiness Management Exposition: For Priority Aero Maintenance2012Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    The economic crisis has affected the airline industry as much as it has affected all other industries in the world. The small airlines and maintenance organisations must find new opportunities and options in order to survive the harsh crisis. Priority Aero Maintenance is now an approved maintenance organisation performing maintenance on aircrafts, engines and components. The company sees economic gains in the future by becoming an approved organisation that follows the European Aviation Safety Agency guidelines (EASA) and meets the requirements outlined in the rules of Part-M.

    In order for the company to become an approved organization, responsible for continuing airworthiness of aircraft, a handbook should be presented to the local authority. This handbook describes the company’s responsibility for the continuing airworthiness in order for the authorities to get an insight into the company and its work.

    This thesis resulted in a draft of CAME (Continuing Airworthiness Management Exposition) and this draft has been approved by Priority Aero Maintenance.

    The CAME will in the future be used by the company as a basis for developing a more detailed manual to be presented to and approved by the Swedish Aviation Authority (Transportstyrelsen).

  • 9.
    Aires, Filipe
    et al.
    Estellus, Paris.
    Prigent, Catherine
    Estellus, Paris.
    Orlandi, Emiliano
    Cologne university.
    Milz, Mathias
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Eriksson, Patrick
    Chalmers University of Technology.
    Crewell, Susanne
    Cologne university.
    Lin, Chung-Chi
    ESA, ESTEC.
    Kangas, Ville
    ESA, ESTEC.
    Microwave hyperspectral measurements for temperature and humidity atmospheric profiling from satellite: The clear-sky case2015Inngår i: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 120, nr 21, 11334-11351 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study investigates the benefits of a satellite HYper-spectral Microwave Sensor (HYMS) for the retrieval of atmospheric temperature and humidity profiles, in the context of Numerical Weather Prediction (NWP). In the infrared, hyper-spectral instruments have already improved the accuracy of NWP forecasts. Microwave instruments so far only provide observations for a limited number of carefully selected channels. An information content analysis is conducted here to assess the impact of hyper-spectral microwave measurements on the retrieval of temperature and water vapor profiles under clear-sky conditions. It uses radiative transfer simulations over a large variety of atmospheric situations. It accounts for realistic observation (instrument and radiative transfer) noise and for a priori information assumptions compatible with NWP practices. The estimated retrieval performance of the HYMS instrument is compared to those of the microwave instruments to be deployed on board the future generation of European operational meteorological satellites (MetOp-SG). The results confirm the positive impact of a HYMS instrument on the atmospheric profiling capabilities compared to MetOp-SG. Temperature retrieval uncertainty, compared to a priori information, is reduced by 2 to 10%, depending on the atmospheric height, and improvement rates are much higher than what will be obtained with MetOp-SG. For humidity sounding these improvements can reach 30%, a significant benefit as compared to MetOp-SG results especially below 250 hPa. The results are not very sensitive to the instrument noise, under our assumptions. The main impact provided by the hyper-spectral information originates from the higher resolution in the O2 band around 60 GHz. The results are presented over ocean at nadir but similar conclusions are obtained for other incidence angles and over land

  • 10.
    Al, Goran
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Boge, Kasper
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Metod för att säkra innehållet i Scania lastbilars underhållsprogram: Tillämpning av MSG-3 processen från flygindustrin2012Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
  • 11.
    Al Hamrani, Emad
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Al-Dulaimi, Anmar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Framtida installationskrav på Electronic Flight Bags (EFB): Med hänsyn till litiumbatterier2017Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    This degree project studies the future regulations for the installation of electronic flight bags (EFB) with focus on the hardware and its safety implications in which the task was given by Bromma Air Maintenance (BAM). The aim is to ease the operator to handle issues dealing with EFB; such as lithium battery fire in the cockpit, placement of EFB in the cockpit, etc. This also addresses flight safety, flight controls, emergency evacuation and solutions in dealing with such issues. Flight safely is a vital factor to be considered since it jeopardizes lives. As recent reports indicate an increase in lithium battery powered devices incidents on aircrafts, this paves the way to find new solutions and procedures to mitigate them. By studying the current regulations, Acceptable Means of Compliance (AMC), Advisory Circular (AC) regarding the usage/installation of EFB and future regulation draft (NPA) this study analyzed the changes, which indicated that there were not many significant changes made to the future regulation (new AMC). Although many chapter of the current AMC have been removed and introduced into a new section under AMC & GM (Guidance Material). Different placement of the EFB in cockpit has also been studied in this degree project, which has shown that depending on the placement choice of the aircraft operator there are advantages and disadvantages. This follows by studying the lithium (Li-ion) batteries: technology, mitigation of fire and procedures for lithium battery fire while also studying the recent incidents regarding lithium batteries fire and explosion in commercial and cargo flights. The solutions consist of using the latest technology to propose a new approach to charge the batteries, and store the burning batteries as well. This lead to a smart inductive charger and a smart fire contamination bag to be integrated into the procedures.

  • 12.
    Alaniz, Monica
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    Belyayev, Serhiy
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    Bergman, David
    Casselbrant, Gustav
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    Honeth, Mark
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    Huang, Jiangwei
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    Ivchenko, Nickolay
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Laukkanen, Mikko
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    Michelsen, Jacob
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    Pronenko, Vira
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    Paulson, Malin
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    Schlick, Georg
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    Tibert, Gunnar
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    Valle, Mario
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strukturmekanik.
    The SQUID sounding rocket experiment2011Inngår i: Proceedings of the 20th ESA Symposium on European Rocket and Balloon Programmes and Related Research, European Space Agency, 2011, 159-166 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The objective of the SQUID project is to develop and in flight verify a miniature version of a wire boom deployment mechanism to be used for electric field measurements in the ionosphere. In February 2011 a small ejectable payload, built by a team of students from The Royal Institute of Technology (KTH), was launched from Esrange on-board the REXUS-10 sounding rocket. The payload separated from the rocket, deployed and retracted the wire booms, landed with a parachute and was subsequently recovered. Here the design of the experiment and post fight analysis are presented.

  • 13.
    Ali, Sheikh Nawaz
    et al.
    Birbal Sahni Institute of Palaeobotany, Lucknow.
    Shekhar, Mayank
    Birbal Sahni Institute of Palaeobotany, Lucknow.
    (Pandey, Pratima
    Indian Institute of Technology, Bombay.
    Bhardwaj, Anshuman
    Snow and Avalanche Study Establishment, Defence Research and Development Organization (DRDO), Him Parisar, Sector-37A, Chandigarh.
    Singh, Shaktiman
    Department of Environmental Science, School of Basic Sciences and Research, Sharda University, Greater Noida.
    Indian Himalayan capacity and adaptation programme: capacity-building in Himalayan glaciology2014Inngår i: Current Science, ISSN 0011-3891, Vol. 106, nr 3, 346- s.Artikkel i tidsskrift (Annet vitenskapelig)
  • 14.
    Allam, Sabry
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Åbom, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Advanced experimental procedure for in-duct aero-acoustics2006Inngår i: 13th International Congress on Sound and Vibration 2006, ICSV 2006, 2006, 1185-1192 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The purpose of this paper is to present a method for characterization of in-duct aero-acoustic sources that can be described as active acoustic two-ports. The method is applied to investigate the sound produced from an orifice plate. The motivation is to obtain better data for the development of improved prediction methods for noise from flow singularities, e.g., in HVAC systems on aircrafts. Most of the earlier works fall into two categories; papers modeling the scattering of acoustic waves and papers modeling the sound generation. Concerning the scattering it is possible to obtain estimates of the low frequency behavior from linear perturbations of the steady state equations for the flow. Concerning the sound generation most of the presented work is experimental and follows a paper by Nelson&Morfey, which present a scaling law procedure for the in-duct sound power based on a dipole model of the source. One limitation with the earlier works is that the sound power only was measured on the downstream side. Also data was only obtained in 1/3-octave bands, by measuring the sound radiated from an open duct termination. Assuming plane waves and linear acoustics the flow duct singularity can be completely modeled as an active 2-port. The experimental determination of its properties is done in a two steps procedure. In the first step the passive data, i.e., the scattering matrix S, is determined using external (independent) sources. In the second step the S matrix is used and the source vector is determined by testing the system with known acoustic terminations.

  • 15.
    Amadori, Kristian
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska högskolan.
    Melin, Tomas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Staack, Ingo
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Multidisciplinary Optimization of Wing Structure Using Parametric Models2013Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Aircraft design is an inherently multidisciplinary activity that requires integrating different models and tools to reach a well-balanced and optimized product. At Linköping University a design framework is being developed to support the initial design space exploration and the conceptual design phase. Main characteristics of the framework are its flexible database in XML format, together with close integration of automated CAD and other tools, which allows the developed geometry to be directly used in the subsequent preliminary design phase. In particular, the aim of the proposed work is to test the framework by designing, optimizing and studying a transport aircraft wing with respect to aerodynamic, geometry, structural and accessability constraints. The project will provide an initial assessment of the capability of the framework, both in terms of processing speed and accuracy of the results.

  • 16.
    Ambre, Rombaut
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Landing the Propellant Stage of a launcher2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    To reduce the cost of launch, several aerospace companies are exploring the possibility of partly reusable launchers. In order to be reusable with minimum refurbishment cost the reusable part of the launcher has to suffer little damage and land in optimal conditions. In this paper, a guidance algorithm to achieve the return of the reusable vehicle on ground through a vertical landing is described. Different mission scenarios are taken into account and the performance of the guidance algorithm is assessed using a 6 Degrees Of Freedom simulator.

  • 17.
    Amin, Rebin
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Tool for Risk Evaluation2017Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
  • 18. Amoignon, Olivier
    et al.
    Pralits, Jan O.
    Hanifi, Ardeshir
    Swedish Defence Research Agency.
    Berggren, M.
    Henningson, Dan S.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Stabilitet, Transition, Kontroll.
    Shape optimization for delay of laminar-turbulent transition2006Inngår i: AIAA Journal, ISSN 0001-1452, E-ISSN 1533-385X, Vol. 44, nr 5, 1009-1024 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A method using gradient-based optimization is introduced for the design of wing profiles with the aim of natural laminar How, as well as minimum wave drag. The Euler equations of gasdynamics, the laminar boundary-layer equations for compressible flows on infinite swept wings, and the linear parabolized stability equations (PSE) are solved to analyze the evolution of convectively unstable disturbances. Laminar-turbulent transition is assumed to be delayed by minimizing a measure of the disturbance kinetic energy of a chosen disturbance, which is computed using the PSE. The shape gradients of the disturbance kinetic energy are computed based on the solutions of the adjoints of the state equations just named. Numerical tests are carried out to optimize the RAE 2822 airfoil with the aim to delay simultaneously the transition, reduce the pressure drag coefficient, and maintain the coefficients of lift and pitch moments. Constraints are also applied on the geometry. Results show a reduction of the total amplification of a large number of disturbances, which is assumed to represent a delay of the transition in the boundary layer. Because delay of the transition implies reduction of the viscous drag, the present method enables shape optimization to perform viscous drag reduction.

  • 19.
    Amro, Adib
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Öberg Sjöstrand, Billy
    För- och nackdelar med att förlänga/förkorta flygets underhållsintervaller2017Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    Abstract

    Aircraft maintenance within the aviation industry is an essential part as the purpose is to maintain the aircrafts built-in security and reliability levels. Aircraft require approved and straightforward maintenance to ensure safe operation and airworthiness. The maintenance program's intention is to ensure that a function operates properly despite an uncertain environment. During flights, aircraft are exposed to a large number of loads, which causes components and parts to be affected negatively. Because of this, a maintenance program is presented, the program tries to constantly detect and correct any potential errors before a functional error occurs.

    This degree project is about finding out about the pros and cons of extending or shortening the maintenance interval within the aircraft maintenance program. In addition, the purpose is to draw conclusions about how airline, aircraft turbine performance and age are related to extension or shortening of this maintenance interval. The dissertation was written at the Academy of Innovation, Design and Technology at Mälardalens högskola, Västerås.

    The work process was carried out in several steps. The first step was to deepen the knowledge within the field and understand the maintenance program. This was done through literature studies and information gathering on the subject. The second step was to analyze and process the general information and answers from the interview questions. The work included the advantages and disadvantages caused by extension or shortening of maintenance intervals without affecting the reliability that maintenance requirements ensure. 

  • 20.
    Andersen, Torben
    et al.
    Lunds universitet.
    Enmark, Anita
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Integrated Modeling of Telescopes2011Bok (Annet vitenskapelig)
  • 21.
    Andersson, Daniel
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    The performance of an iced aircraft wing2011Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The goal of this thesis work has been to develop and manufacture an ice layer which was to be mounted on the tip of a scaled down wing model. The iced wing should be tested in a wind tunnel and aerodynamic comparisons should be made to the same wing without ice.The development of the ice was carried out as a modified product development process. The main differences are that there is no costumer and that the actual shape and functions of the product are more or less predetermined. The challenge was to find the best way to create the ice layer and how to mount it to the wing without damaging it or covering any pressure sensors. Product development methods such as pros and cons lists and prototypes were used to solve problems before printing the plastic ice layer in a rapid prototyping machine.Wind tunnel experiments were then conducted on the wing with and without the manufactured ice. Raw data from the wind tunnel were processed and lift and drag coefficients were calculated using mathematical equations. Finally, conclusions were drawn by comparing the results from the wind tunnel tests with theory, other works as well as CFD simulations.The ice layer was successfully manufactured and it met the target specifications. The aerodynamic performance of an iced aircraft wing proved to be considerably worse compared to a blank wing. The maximum achievable lift force decreased by 22% and an increased drag force will require more thrust from the airplane.

  • 22.
    Andersson, Erik
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET).
    Bengtsson, Per-Johan
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET).
    Dark Ages Lunar Interferometer (DALI): Deployment-Rover - Mobility System2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This thesis is issued in collaboration with the Jet Propulsion Laboratory (JPL) in Pasadena, California. JPL's primary function is the construction and operation of robotic planetary spacecraft. At the time being JPL has 22 spacecraft and 10 instruments conducting active missions.

    The "Dark Ages" represent the last frontier in cosmology, the era between the genesis of the cosmic microwave background (CMB) and the formation of the first stars. During the Dark Ages, when the Universe was unlit by any star, the only detectable signal is likely to be that from neutral hydrogen (HI).

    The HI absorption occurs in dark matter-dominated overdensities, locations that will later become the birthplaces of the first stars. Tracing this evolution will provide crucial insights into the properties of dark matter and potentially reveal aspects of cosmic inflation. This could be accomplished using a radio telescope located on the far side of the Moon, the only site in the solar system shielded from human-generated interference and, at night, from solar radio emissions.

    Our objective has been the development of the concept of an autonomous rover that would be capable of deploying a large number of low frequency radio antennas on the lunar surface. This is an enabling task for the eventual creation of a radio telescope.

    The project at Halmstad University was divided into three sub-projects, where our area of responsibility has been the development of a concept of the rover's mobility system.

    The result of the project is the concept of a "Rocker-Bogie" suspension system, created in a 3D-environment. A concept which underwent a series of digital analyses and simulations to ensure the compliance with required specifications.

  • 23.
    Andersson, Henric
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska högskolan.
    Herzog, Erik
    Saab Aeronautics, Linköping, Sweden.
    Ölvander, Johan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska högskolan.
    Experience from Model and Software Reuse in Aircraft Simulator Product Line Engineering2013Inngår i: Information and Software Technology, ISSN 0950-5849, Vol. 55, nr 3, 595-606 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Context: "Reuse" and "Model Based Development" are two prominent trends for improving industrial development efficiency. Product lines are used to reduce the time to create product variants by reusing components. The model based approach provides the opportunity to enhance knowledge capture for a system in the early stages in order to be reused throughout its lifecycle. This paper describes how these two trends are combined to support development and support of a simulator product line for the SAAB 39 Gripen fighter aircraft.

    Objective: The work aims at improving the support (in terms of efficiency and quality) when creating simulation model configurations. The objective is to increase the level of reuse when combining and customizing models for usage in a range of development and training simulators.

    Method: The research has been conducted with an interactive approach using prototyping and demonstrations, and the evaluation is based on an iterative and a retrospective method.

    Results: A product line of simulator models for the SAAB 39 Gripen aircraft has been analyzed and defined in a Product Variant Master. A configurator system has been implemented for creation, integration, and customization of stringent simulator model configurations. The system is currently under incorporation in the standard development process at SAAB Aeronautics.

    Conclusion: The explicit and visual description of products and their variability through a configurator system enables better insights and a common understanding so that collaboration on possible product configurations improves and the potential of software reuse increases. The combination of application fields imposes constraints on how traditional tools and methods may be utilized. Solutions for Design Automation and Knowledge Based Engineering are available, but their application has limitations for Software Product Line engineering and the reuse of simulation models.

  • 24.
    Andersson, Magnus
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Eriksson, Peter
    Analysis of noise levels, audio frequency and fuel consumption with propellers of type McCauley and MT on BAe Jetstream 322012Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    This report describes a thesis project conducted at Direktflyg in Borlänge, in early 2012, where the aim was to analyse the difference in noise level, audio frequency and fuel consumption between propellers of the older type McCauley and the newer type MT on the aircraft type BAe Jetstream 32. To perform the analysis, the authors reviewed current procedures regarding noise certification from air safety agencies to be able to identify suitable methods for the noise level and audio frequency measurements. The results of the conducted noise level measurements show a general lower noise level throughout the cabin and a significant reduction in noise level behind row 2 when using the MT propeller compared to the McCauley type. In practice this means a lower perceived noise level for most passengers at an average passenger load factor. The frequency measurements show that the MT propeller generates audio frequencies which are perceived as lower in noise levels and are therefore more comfortable for passengers. The fuel consumption was also slightly lower when using the MT propeller compared to the McCauley type over the assigned time period and the determined limiting parameters.

  • 25.
    Andersson, Staffan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Verifieringsinformation: En kvalitativ studie2012Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Den här rapporten handlar om hur en optimal nivå på verifieringsinformation i kontrakt skall uppnås. När kontrakten skrivs finns begränsad information framme. Det finns kundkrav men systemkonstruktionen är inte fastställd. Radarsystem är väldigt komplexa produkter vilket leder till att det är många år mellan kontrakt och slutleverans. Under tiden utvecklas ny teknik som kan leda till att konstruktionen behöver ändras. Således påverkas acceptanstesten och diskussioner kan uppstå mellan tillverkare och kund.

    Diskussionerna kan bero på för lite information i början av kontraktet vilket leder till att tillverkare och kund kan ha olika målbild. I motsats, för mycket information ger problem om fel information har framkommit och om konstruktionen ändras uppstår diskussioner. 

  • 26.
    Aoudia, Thomas
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Aircraft Performance Monitoring on Contaminated Runways2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Operations on contaminated runways are a permanent challenge for the aviation community. Among the stakeholders, Airbus has decided to improve its knowledge by developing a fast post-processing software aiming at quickly identifying the runway state on operational recordings. First and foremost, the context of operations on contaminated runways is presented, with a particular emphasis on runway condition assessment methods. In a second part, the models embedded in this function are validated against simulation and more elaborated flight test analysis software. Then, the identification algorithm is validated by comparing its outputs to actual operational conditions. Finally, the robustness of the identification is assessed.

  • 27.
    Arjoni, D. H.
    et al.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campo, Brazil.
    Rocha, G. C.
    Konatus, São José dos Campo, Brazil.
    Moreira, A. H.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campo, Brazil.
    Nicola, R. M.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campo, Brazil.
    Oliveira, W. R.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campo, Brazil.
    Silva, A. V. S.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campo, Brazil.
    Natal, G. S.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campo, Brazil.
    Silveira, L.
    NAC, São José dos Campo, Brazil.
    Thomas, E.
    Embraer, São José dos Campo, Brazil.
    Villani, E.
    TA Instituto Tecnológico de Aeronáutica, São José dos Camp, Brazil.
    Trabasso, Luís Gonzaga
    TA Instituto Tecnológico de Aeronáutica, São José dos Camp, Brazil.
    Experimental Evaluation of the Human Performance on a RoboticFlight Simulator based on FOQA Parameters2016Inngår i: Proceedings of the Aerospace Technology Congress / [ed] Kaj Lundahl, Roland Karlsson, Björn Jonsson and Knut Övrebö, Stockholm, 2016, Vol. 1, 1-11 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The SIVOR project, currently being developed by ITA and Embraer, consists of designing andimplementing a high fidelity flight simulator based on the use of COTS industrial robots. The aim of theproject is to provide a cost-efficient and flexible platform that can be used along the design phases of theaircraft. One of the advantages of an industrial robot over the traditional Stewart platform is theavailability of a large workspace, which provides more flexibility for defining the washout filter. Thisfilter converts the aircraft dynamics into robot movements, which has a limited workspace. The mainpurpose of the flight simulator is to provide a motion feeling similar to the one imposed by the aircraftmovements in a real flight. The representativeness of the motion cue is usually evaluated in a qualitativeway by the pilots that fly the simulator. Quantitative methods to evaluate the entire range of actuation of asimulator are complex, inducing tests in fractions of the flight to increase performance. In this work, wediscuss the use of FOQA (Flight Operational Quality Assurance) as an additional quantitative tool for theevaluation of the motion cue in the SIVOR flight simulator. FOQA is a voluntary safety program fromFAA, detailed in AC-120-82. It proposes a set of parameters that can be used by airliners to analyse flightsafety and increase operational efficiency. The verification of FOQA parameters checks whether or notthe pilot complies with the standard operational procedures defined by the airliners and aircraftmanufacturers. The purpose of this work is to analyse whether or not, and to what extent, the FOQAparameters can be used to evaluate the quality of the motion cue of flight simulators. For this purpose, wedefine an experimental procedure that compares flights performed by pilots under different motionmodes. It then calculates a set of behavioural parameters that has been proposed in order to quantify howthe motion affects the inputs of the pilot. The results are submitted to ANOVA statistical analysis thatverifies the relevance of the motion factor. Finally, we discuss the capability of a FOQA basedexperiment to estimate the contribution of the motion to the realism of the flight simulation.

  • 28.
    Arnal, Daniel
    et al.
    ONERA.
    Tran, Dac
    Dassault Aviation.
    Hein, Stefan
    DLR.
    Hanifi, Ardeshir
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Stabilitet, Transition, Kontroll. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Engelbrecht, T.
    SUPERsonic TRAnsition Control Contract N° AST4-CT-2005-516100: Final Technical Report2008Rapport (Annet vitenskapelig)
  • 29.
    Arridge, Christopher S.
    et al.
    Mullard Space Science Laboratory, Department of Space and Climate Physics.
    Agnor, Craig B.
    University of Manchester, School of Physics and Astronomy.
    André, Nicolas
    Centre d’Etude Spatiale des Rayonnements, Toulouse.
    Baines, Kevin H.
    NASA Jet Propulsion Laboratory, Pasadena.
    Fletcher, Leigh N.
    Gautier, Daniel
    LESIA, CNRS-Observatoire de Paris.
    Hofstadter, Mark D.
    NASA Jet Propulsion Laboratory, Pasadena.
    Jones, Geraint H.
    Mullard Space Science Laboratory, Department of Space and Climate Physics.
    Lamy, Laurent
    LESIA, CNRS-Observatoire de Paris.
    Langevin, Yves
    Institut d'Astrophysique Spatiale.
    Mousis, Olivier
    Institut UTINAM, CNRS, OSU THETA.
    Nettelmann, Nadine
    Universität Rostock.
    Russell, Christopher T.
    Institute of Geophysics and Meteorology, University of Cologne.
    Stallard, Tom
    Physics and Astronomy Department, Ohio University.
    Tiscareno, Matthew S.
    Cornell University, Ithaca.
    Tobie, Gabriel
    LPG, CNRS.
    Bacon, Andrew
    Systems Engineering and Asssessment Ltd..
    Chaloner, Chris
    Systems Engineering and Asssessment Ltd..
    Guest, Michael
    Systems Engineering and Asssessment Ltd..
    Kemble, Steve
    EADS, Astrium.
    Peacocke, Lisa
    EADS, Astrium.
    Achilleos, Nicholas
    Physics and Astronomy Department, Ohio University.
    Andert, Thomas P.
    Universität der Bundeswehr.
    Banfield, Don
    Cornell University, Ithaca.
    Barabash, Stas
    Swedish Institute of Space Physics.
    Martin-Torres, Javier
    Centre for Astrobiology, Madrid.
    Zarka, Philippe
    LESIA, CNRS-Observatoire de Paris.
    Uranus Pathfinder: Exploring the origins and evolution of Ice Giant planets2012Inngår i: Experimental astronomy (Print), ISSN 0922-6435, E-ISSN 1572-9508, Vol. 33, nr 2-3, 753-791 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The "Ice Giants" Uranus and Neptune are a different class of planet compared to Jupiter and Saturn. Studying these objects is important for furthering our understanding of the formation and evolution of the planets, and unravelling the fundamental physical and chemical processes in the Solar System. The importance of filling these gaps in our knowledge of the Solar System is particularly acute when trying to apply our understanding to the numerous planetary systems that have been discovered around other stars. The Uranus Pathfinder (UP) mission thus represents the quintessential aspects of the objectives of the European planetary community as expressed in ESA's Cosmic Vision 2015-2025. UP was proposed to the European Space Agency's M3 call for medium-class missions in 2010 and proposed to be the first orbiter of an Ice Giant planet. As the most accessible Ice Giant within the M-class mission envelope Uranus was identified as the mission target. Although not selected for this call the UP mission concept provides a baseline framework for the exploration of Uranus with existing low-cost platforms and underlines the need to develop power sources suitable for the outer Solar System. The UP science case is based around exploring the origins, evolution, and processes at work in Ice Giant planetary systems. Three broad themes were identified: (1) Uranus as an Ice Giant, (2) An Ice Giant planetary system, and (3) An asymmetric magnetosphere. Due to the long interplanetary transfer from Earth to Uranus a significant cruise-phase science theme was also developed. The UP mission concept calls for the use of a Mars Express/Rosetta-type platform to launch on a Soyuz-Fregat in 2021 and entering into an eccentric polar orbit around Uranus in the 2036-2037 timeframe. The science payload has a strong heritage in Europe and beyond and requires no significant technology developments. © 2011 Springer Science+Business Media B.V.

  • 30.
    Atreya, Sushil
    et al.
    University of Michigan.
    Squyres, Steve
    Cornell University, Ithaca.
    Mahaffy, Paul
    Goddard Space Flight Center, Greenbelt, Maryland.
    Leshin, Laurie
    Rensselaer Polytechnic Institute, Troy, New York.
    Franz, Heather
    Goddard Space Flight Center, Greenbelt, Maryland.
    Trainer, Melissa
    Goddard Space Flight Center, Greenbelt, Maryland.
    Wong, Michael
    University of Michigan.
    McKay, Christopher
    NASA Ames Research Center, Moffett Field.
    Navarro-Gonzalez, Rafael
    Universidad Nacional Autónoma de México.
    Martin-Torres, Javier
    Centro de Astrobiología (CSIC-INTA), Madrid.
    MSL/SAM Measurements of Non Condensable Volatiles, Comparison with Viking Lander, and Implications for Seasonal Cycle2013Konferansepaper (Fagfellevurdert)
  • 31.
    Auenmüller, Christoph
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Automated Controller Design for a Missile Using Convex Optimization2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The focus of the present master thesis is the automation of an existing controllerdesign for a missile using two aerodynamic actuating systems. The motivation isto evaluate more missile concepts in a shorter period of time.The option used is trimming and linearization of a highly nonlinear missile at specic conditions. According to these conditions, either a two-dimensional operatingpoint grid dened by Mach number and height or three-dimensional operatingpoint grid dened by Mach number, height and angle of attack is generated forthe whole operating range of the missile. The controllers are designed at thesepoints using convex optimization. The convex set denes the pole placement areawhich is constrained by linear matrix inequalities according to the dynamic behaviorof the missile at the operating point conditions. These controllers describea validity area where the missile can be stabilized. This area consists all neighboringoperating points and denes therefore the grid density which can dier atspecic regions of the operating range. Controlling the missile to the target makesit necessary to apply gain-scheduling in order to get the manipulated variable byinterpolation of adjacent operating points. During this blending of the controllersa problem called windup can occur when an actuator is saturated. This mightlead to instability in worst case but can be counteracted by a model-recovery antiwindupnetwork which guarantees stability in the presence of saturation. Thisanti-windup design is automated by an ane linear parameter dependency of thegrid parameters and has the same validity area like the controllers.The whole design was successfully developed and tested in MATLAB/Simulink onmissiles using one or two aerodynamic actuating systems. The controllers have agood performance at small and high acceleration steps and the anti-windup keepsthe missile stable even though the actuators are saturated. Stability and robustnessof the controllers and anti-windup networks was veried as well as an airdefense maneuver where the missile starts at the ground and intercepts a targetat high altitude was successfully simulated for dierent grids and missiles.

  • 32. Austrin, L.
    et al.
    Torabzadeh Tari, Mohsen
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Larsson, A.
    Analysis of a feasible pulsed-power supply system for an Unmanned Aerial Vehicle2006Inngår i: ICAS-Secretariat, 2006, 3605-3612 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    More Electric Aircraft technology enables the power supply of electric energy weapons such as high-power microwave and laser weapons. Aspects of electric power generation, energy storage, distribution and pulse-conditioning systems for the power supply of directed energy weapons in Unmanned Aerial Vehicle are addressed in this paper. A trend in aircraft design is to electrify more parts of the aircraft via the concept of More Electric Aircraft (MEA) and its technology which allows for increased electric power consumption. Thus, MEA technology enables the power supply of weapons and protection systems that are using electric energy. Among these devices directed energy weapons such as high-power microwave (HPM) and laser weapons are feasible. Such systems require high power pulsed electric energy with, thus imposing new requirements of on-board power supplies. In the demonstrated concept it is important to analyze power losses and efficiency as well as weight and volume in order to evaluate the possibility to adapt the system in an UAV.

  • 33.
    Avasak, Kalyani
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Institute of Space Systems, University of Stuttgart.
    Mission Analysis and Trajectory optimisation for project CAPE2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Atmospheric reentry is a challenging part of human space ight and planetary entry missions.At the Institute of Space Systems in University of Stuttgart the idea of projectCAPE was conceived in 2012. Project Cubesat Atmospheric Probe for Education aimsto demonstrate the capability of miniaturised technologies of the micro electric plasmathruster, reentry vehicle design and ablative shielding material developed in this institute.The mission scenario is such that the CAPE is being deployed from the InternationalSpace Station and needs to complete the de-orbit of the Service and deorbit module andre-entry of the Atmospheric entry module in less than 1 year. The Cube satellite weighs3.0 kg consisting of a 2+1 unit service design module with solar panels, pulsed plasmapropulsion system of the university of Stuttgart (PETRUS) and a micro atmosphericreentry module (MIRKA-2). This reentry vehicle is unique in its size and weighs 0.5kg. During its reentry phase, it will be subjected to the intense aero-thermal loads at theThermal Protection System front which are absorbed by its ablative heat shield. But thecharacteristics of the re-entry trajectory like the ight path angle, entry velocity and entrypoint greatly determine the survivability against the integral heat load for this ballisticreentry vehicle. Although the success of the mission is considerably higher when having acontrolled reentry, in case of ballistic vehicles it is solely determined by the mission design.The main task is to investigate and develop the optimal re-entry trajectories in thedesign-time phase of mission development for MIRKA-2 vehicle that satises the objectiveof minimizing heat loads and adhering to operational constraints. Thus, the aimof this thesis is to provide a novel solution and optimum trajectory of the de-orbit andre-entry ight to maximize the survivability of the reentry module. The con icting parametersin this mission would be the operational limit of the pulsed plasma thruster andminimum heat loads during reentry ight. The simulation of these trajectories is carriedout in MATLAB using the REENT software developed in the Institute of Space Systems,University of Stuttgart. Its source code is composed in Fortran 77 which is integratedinto MATLAB. A careful mission analysis with the constraints of the capacity of pulsedplasma thruster, impulse provided by the separation mechanism and survivability of thereentry vehicle is carried out to prove the feasibility of this mission. In order to accomplishthe survivability during re-entry the aspects that have been modelled are the ight dynamicsof the satellite, aerodynamic and aero-thermal loads, spacecraft behaviour underthe external loads and local heating process.

  • 34.
    Axelsson, Katarina
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Studies of auroral processes using optical methods2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The Aurora is a visual manifestation of the complex plasma processes that occur as the solar wind interacts with the Earth’s magnetosphere and ionosphere. Therefore, studies of the aurora can lead to better understanding of the near-Earth space environment and of fundamental physical processes.This thesis focuses on optical studies of the aurora, both ground-based observations using the Auroral Large Imaging System (ALIS) and measurements from instruments onboard the Japanese micro-satellite Reimei. Various properties of the aurora are studied, such as the characteristic energy of precipitating electrons and scale sizes of diffuse auroral structures. Our understanding of the ionospheric physical processes involved in a particular auroral emission is improved using conjugate particle and optical data.Auroral light is a result of radiative transitions between excited states of the ionospheric gases. These excited states are formed either by direct electron impact or by a series of more complicated processes, involving chemical reactions, where part of the energy is converted into auroral light. Studies of auroral emissions can therefore give information about primary particle fluxes, ionospheric composition, and the magnetospheric and ionospheric processes leading to auroral precipitation. One way of deducing the characteristic energy of the precipitating particles is by using intensity ratios of auroral emissions. To be reliable, this method requires a good understanding of the processes involved in the auroral emissions used. The method works well if the measurements are made along the geomagnetic field lines. Using data from ALIS, both in magnetic zenith and off magnetic zenith, this method is tested for angles further away from the direction of the magnetic field lines. The result shows that it is possible to use this technique to deduce the characteristic energy for angles up to 35 degrees away from magnetic zenith.Using ALIS we have also been able to study structures and variations in diffuse aurora. When mapped to the magnetosphere, this provides information about the characteristics of the modulating wave activity in the magnetospheric source region. A statistical study of the scale sizes of diffuse auroral structures was made and the result shows widths and separation between structures of the order of 13-14 km. When mapped to the magnetosphere, this corresponds to 3-4 ion gyro radii for protons with a typical energy of 7 keV. Magnetometer data show that the structures move southward with a speed close to zero in the plasma convection frame. Stationary mirror mode structures in the magnetospheric equatorial plane are a likely explanation for these diffuse auroral structures. In another study we use measured precipitating electron energy spectra to improve our understanding of how the auroral process itself relates to the 427.8 nm auroral emission, which is often used when studying intensity ratios between different emission lines. The 427.8 nm emission is a fairly simple emission to model, with only a few processes involved, but still has some uncertainties, mostly due to the excitation cross section. Simultaneous measurements of the intensity of this emission from ALIS and the intensity and electron flux from Reimei provide a way to evaluate different sets of cross sections in order to find the best fit to the experimental data. It also allows a comparison of the absolute calibration of ALIS and Reimei imagers, improving the possibility to use the space-borne data for other detailed quantitative studies.In order to compare absolute measurements of aurora using different imagers, optical instruments are usually absolute calibrated by exposing them to a calibration light source. In 2011 an intercalibration workshop was held in Sodankylä, Finland, where nine low light sources were compared to the radioactive Fritz Peak reference source. The results were compared with earlier calibration workshop results and show that the sources are fairly stable. Two sources were also calibrated with the calibration standard source at UNIS, Svalbard, and the results show agreement with the calibration workshop in Sodankylä within 15 to 25%. This confirms the quality of the measurements with ALIS and in turn also of the the Reimei imagers.

  • 35.
    Axelsson, Katarina
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Sergienko, T.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Nilsson, H.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Brändström, U.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Asamura, K.
    Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara.
    Sakanoi, Takeshi
    Tohoku University, Graduate School of Science, Sendai, Japan.
    First negative system of N2 + in aurora: Simultaneous space-borne and ground-based measurements and modeling results2014Inngår i: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 32, nr 5, 499-506 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The auroral emission of the first negative system of N2 + at 427.8 nm is analyzed using simultaneous measurements from the ground with ALIS (Auroral Large Imaging System) and from space with optical (MAC) and particle (ESA) instruments of the Reimei satellite. The study has two main objectives. The first is validation of the absolute calibration of the ALIS and the Reimei MAC cameras. The other task is to evaluate different cross sections of the electron excitation of N2 + that are used for the modeling of the auroral 1N system emissions. The simultaneous measurements of the 427.8 nm emission by ALIS and Reimei imagers show excellent agreement, indicating that the calibration of the two instruments is correct. Comparison of the 427.8 nm emission intensity calculated using the incident electron flux measured by the Reimei particle instruments with intensities measured by the optical imagers show that the best match is reached with the cross section from Shemansky and Liu (2005).

  • 36.
    Axelsson, Katarina
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Sergienko, T.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Nilsson, H.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Brändström, U.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Ebihara, Y.
    Research Institute for Sustainable Humanosphere, Kyoto University.
    Asamura, K.
    Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara.
    Hirahara, M.
    Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo.
    Spatial characteristics of wave-like structures in diffuse aurora obtained using optical observations2012Inngår i: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 30, nr 12, 1693-1701 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present the results of a statistical study using optical images from ALIS (Auroral Large Imaging System) to investigate the spatial and temporal variations of structures in diffuse aurora. Analysis of conjugate Reimei data shows that such fine structures are a result of modulation of high-energy precipitating electrons. Pitch angle diffusion into the loss cone due to interaction of whistler mode waves with plasma sheet electrons is the most feasible mechanism leading to high-energy electron precipitation. This suggests that the fine structure is an indication of modulations of the efficiency of the wave-particle interaction. The scale sizes and variations of these structures, mapped to the magnetosphere, can give us information about the characteristics of the modulating wave activity. We found the scale size of the auroral stripes and the spacing between them to be on average 13-14 km, which corresponds to 3-4 ion gyro radii for protons with an energy of 7 keV. The structures move southward with a speed close to zero in the plasma convection frame.

  • 37.
    Axelsson, Katarina
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Sergienko, T.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Sandahl, Ingrid
    Brändström, U.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    A study on the possibility to deduce the 2D distribution of the auroral electron precipitation from multi wavelength optical measurements with auroral imagers2011Inngår i: Óptica Pura y Aplicada, ISSN 0030-3917, E-ISSN 2171-8814, Vol. 44, nr 4, 605-609 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The intensity ratios of auroral emissions at different wavelengths are widely used for reconstruction of auroral electron parameters. This method works quite well if the measurements of the auroral emissions are conducted in the magnetic zenith direction. In this study we want to investigate the possibility to use the intensity ratio method in the case where the observations are made in a direction not parallel to the magnetic field. In particular, we want to check the possibility of using auroral data for deducing the 2D distribution of the auroral electron precipitation. We use ALIS multi-station measurements of the auroral red and green line emissions (6300 Å and 5577 Å) to get data in zenith and non-zenith directions. We also take into account that the red line emission peak and the green line emission peak are at different altitudes. The results of this investigation show we can obtain reliable results for angles up to 35º away from magnetic zenith.

  • 38.
    Azari, Pouyan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    An Orbit Control System for UWE-4 Using the High Fidelity Simulation Tool Orekit2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Cubesats are picosatellites that have a mass of less than 1.3kg and have a shape of acube. As a result of their low cost of development and launch, cubesats are gainingpopularity in industry and academia. These satellites are also a cost-efective way forspace technology demonstrations. University of Würzburg has a longstanding cubesatprogram started with the launch of UWE-1 in 2005. This was followed by UWE-2 andUWE-3. Several technologies were tested and validated using the UWE platform. Thelast mission UWE-3 has successfully tested an attitude control system.In the next mission, UWE-4 will demonstrate an orbit control system.

    Being a picosatellite as small as this one (10 x 10 x 10cm 3 and 1kg) brings new challenges intodi↵erent aspects of satellite design, development, control and operation. The orbit con-trol of such a satellite is one of the problems that should be tackled. Being such a smallsatellite means having less propellant mass and much smaller thrusters than conventionalsatellites. These should be addressed in the orbit control.

    UWE-4 will take advantage of four NanoFEEP thrusters, on one side. Because of theiraccuracy and functionality, these thrusters can be used to implement a continuous thrustsystem. They are also a good choice because of their low energy usage. This work startswith the preparation that was needed to implement a control system. Then explains thestate of the art for continuous thrust control systems. Implements two di↵erent methods,based on perfect control and discusses the outcome. It discuses the limiting factors, likefuel mass, available electrical energy and their e↵ect on the controller performance andconcludes with recommendation for the future researches.

  • 39.
    Backman, Fredrick
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Från föhn till feu!: Esrange och den norrländska rymdverksamhetens tillkomsthistoria från sekelskiftet 1900 till 19662010Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This essay is about the origin, planning and establishment of the European Space Research Organisation's (ESRO) sounding rocket base Esrange outside Kiruna in Northern Sweden. Three main questions are examined. First I show there were not just scientific and technical but also political, economical as well as military reasons to build a European rocket base. Second, I scrutinize the reasons to choose Northern Sweden as the location for the rocket base. As it turns out, the main reasons were the favourable location of Northern Sweden within the aurora oval zone, the proximity of the Kiruna Geophysical Observatory, and the possibility to use a large, although not quite uninhabited, area where the launched rockets could crash. Finally, I examine the difficulty of talking about boundaries of various kinds, such as temporal, spatial and functional. The essay also provides a discussion on possible ways to continue research on this topic.

  • 40.
    Ballard, Claire
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Conceptual lay-out of small launcher2012Independent thesis Advanced level (degree of Master (Two Years)), 30 poäng / 45 hpOppgave
  • 41.
    Ballard, Claire
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Conceptual lay-out of small launcher2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The objective of this diploma thesis is to perform a conceptual lay-out of a small launcher. Re- quirements have been defined in order to realize this first preliminary study and design of a small launcher. In that frame, a MATLAB code has been written in order to simulate the rocket tra- jectories. An optimization program on launcher staging has been written as well. To validate this code, the VEGA and Ariane 5 launchers have been used. Then from studies on existing launchers, simulations have been performed in order to find an optimum small launcher and later on to design more precisely the small launcher. As a requirement an upper stage has been newly designed for the purpose of the study. At the end, two small launchers have been considered: a three-stage launcher using the Zefiro 23 as a first stage, the Zefiro 9 as a second stage, and an upper stage using a 3kN thrust engine; a two-stage launcher using the Zenit booster engine in the first stage, and an upper stage using a 22kN thrust engine.

  • 42. Balmer, G.
    et al.
    Berquand, A.
    Company-Vallet, E.
    Granberg, V.
    Grigore, V.
    Ivchenko, Nickolay
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Kevorkov, R.
    Lundkvist, E.
    Olentsenko, Georgi
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Pacheco-Labrador, J.
    Tibert, Gunnar
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Yuan, Yunxia
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    ISAAC: A REXUS STUDENT EXPERIMENT TO DEMONSTRATE AN EJECTION SYSTEM WITH PREDEFINED DIRECTION2015Inngår i: EUROPEAN ROCKET AND BALLOON: PROGRAMMES AND RELATED RESEARCH, 2015, 235-242 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    ISAAC - Infrared Spectroscopy to Analyse the middle Atmosphere Composition was a student experiment launched from SSC's Esrange Space Centre, Sweden, on 29th May 2014, on board the sounding rocket REXUS 15 in the frame of the REXUS/BEXUS programme. The main focus of the experiment was to implement an ejection system for two large Free Falling Units (FFUs) (240 mm x 80 mm) to be ejected from a spinning rocket into a predefined direction. The system design relied on a spring-based ejection system. Sun and angular rate sensors were used to control and time the ejection. The flight data includes telemetry from the Rocket Mounted Unit (RMU), received and saved during flight, as well as video footage from the GoPro camera mounted inside the RMU and recovered after the flight. The FFUs' direction, speed and spin frequency as well as the rocket spin frequency were determined by analyzing the video footage. The FFU-Rocket-Sun angles were 64.3 degrees and 104.3 degrees, within the required margins of 90 degrees +/- 45 degrees. The FFU speeds were 3.98 m/s and 3.74 m/s, lower than the expected 5 +/- 1 m/s. The FFUs' spin frequencies were 1.38 Hz and 1.60 Hz, approximately half the rocket's spin frequency. The rocket spin rate slightly changed from 3.163 Hz before the ejection to 3.117 Hz after the ejection of the two FFUs. The angular rate, sun sensor data and temperature on the inside of the rocket module skin were also recorded. The experiment design and results of the data analysis are presented in this paper.

  • 43. Barabash, Victoria
    A comparison of PMSE occurrence with energetic particle precipitation detected by riometer in northern Scandinavia2000Inngår i: Proceedings of the 9th International Workshop on Technical and Scientific Aspects of MST Radar- MST9 combined with COST-76 Final Profiler Workshop: Toulouse, France, March 13-18, 2000 / [ed] Belva Edwards, Toulouse: SCOSTEP , 2000Konferansepaper (Annet vitenskapelig)
  • 44. Barabash, Victoria
    Are variations in PMSE intensity affected by energetic particle precipitation?2002Inngår i: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 20, 539-545 s.Artikkel i tidsskrift (Fagfellevurdert)
  • 45. Barabash, Victoria
    ESRAD MST radar analysis of the waves1998Inngår i: Proceedings of the 4th European Symposium on Stratospheric Ozone, Air Pollution Research Report 66, European Commision, 1998, 70-73 s.Konferansepaper (Annet vitenskapelig)
  • 46. Barabash, Victoria
    Leewave observations by the MST radar ESRAD in northen Sweden1999Inngår i: Mesoscale processes in the stratosphere: their effect on the stratospheric chemistry and microphysics ; proceedings of the European workshop 8 to 11 November 1998 Bad Tölz, Bavaria, Germany / [ed] K.S. Carslaw ; G.T. Amanatidis, Luxemourg: European Commission Joint Research Centre, 1999, 233-238 s.Konferansepaper (Annet vitenskapelig)
  • 47. Barabash, Victoria
    MST radar observations of PMSE in Northern Scandinavia during May-August 19971998Inngår i: Proceedings of the Eigth Workshop on Technical and Scientific Aspects of MST Radar : solar-terrestrial energy program: solar-terrestrial energy program ; Bangalore, India, December 15 - 20, 1997 / [ed] Belva Edwards, Boulder, Colo.: SCOSTEP , 1998, 326-329 s.Konferansepaper (Annet vitenskapelig)
  • 48. Barabash, Victoria
    MST-radar lee wave ovservations during winter 1996/97 in northern Scandinavia1997Inngår i: Proceedings of 13th ESA Symposium on Rocket and Baloon Programmes and Related Research, ESA-SP-397, 1997, 179-183 s.Konferansepaper (Annet vitenskapelig)
  • 49. Barabash, Victoria
    Wind profiling with ESRAD, the Esrange radar1997Inngår i: Extended abstracts COST-76 Profiler Workshop: v / [ed] Hans Richner, Zürich: Eidgenössische Technische Hochschule (ETH), Institute for Atmospheric Science , 1997, 70-73 s.Konferansepaper (Annet vitenskapelig)
  • 50. Barabash, Victoria
    et al.
    Chilson, P.
    Kirkwood, S.
    Réchou, A.
    Stebel, K.
    Investigations of the possible relationship between PMSE and tides using a VHF MST radar1998Inngår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 25, nr 17, 3297-3300 s.Artikkel i tidsskrift (Fagfellevurdert)
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