In recent years it has been discovered that the window installations on the Visby class corvette are prone to break. The aim of this report is to perform a structural analysis of three different windowinstallations. Thus, to find which window installation minimizes the risk of leaks and cracks in the attachment connecting the window glass and the hull. The three window installations consist of theexisting window installation and one of SAAB Kockums alternative solutions installed in two different ways, with and without an additional damping mass. The model that will be used in the simulationswill consist of a rectangular shaped carbon fibre composite sandwich plate that represents the side structure of the maneuver deck. Furthermore, it will include three windows where only the middlepositioned window will contain the given installation details in order to reduce the complexity of both the modelling and the simulations. Three load cases were simulated in ANSYS Workbench. Thefirst load case called "hogging" consisted of a bending moment along the vertical sides of the model. The second load case called "slamming" consisted of a vertical force pointing upwards along thebottom of the model. Lastly, a torsion load case was simulated. In all load cases the existing window installation were subjected to the largest strains along the inner edges of the attachment. In theslamming load case, the alternative solution without the double damping mass was exposed to least strains around the inner edges of attachment compared to the other window installations. For thehogging and the torsion load case the alternative solution with double damping mass produced least strains around the inner edges of the attachment. But the alternative solution without the doubledamping mass was also able to reduce the strains around the inner edges compared to the existing window installation. In conclusion, the alternative solution without an additional damping mass isin overall minimizing the strains along the inner edges of the attachment in which the most leaks and cracks have been observed. It has especially been efficient in reducing strains in the slammingload case. Even though the window installation with an additional damping mass best withstands hogging and torsion, the slamming load case is the most common scenario. Therefore, the windowinstallation that best withstands the slamming load case should be prioritized. Thus, the alternative window installation without the additional damping mass is the best alternative because it bestwithstands slamming but also reduces the strains along the inner edges compared to the existing window installation in the other load cases. / Under de senaste åren har det upptäckts att fönsterinstallationerna på Visby-klasskorvetten har en benägenhet att brista. Syftet med denna studie är att utföra en hållfasthetsanalys på tre olikafönsterinstallationer. Därav är målet att hitta den fönsterinstallation som minimerar risken för läckor samt sprickor i smygskarven som kopplar fönsterglaset med skrovet. De tre fönsterinstallationernabestår av den befintliga fönsterinstallationen samt en av SAAB Kockums lösningsförslag installerat på två olika sätt, med och utan dubbel dämpningsmassa. Modellen som ska användasi simuleringarna kommer att bestå av en rektangulär skiva bestående av en sandwichkonstruktion med lamineringar av kolfiberkomposit. Skivan ska motsvara sidan av manöverbryggan. Modellen inkluderartre fönster där endast mittenfönstret kommer att modelleras med de givna detaljerna på samtliga fönsterinstallationerna. Detta för att förenkla både modelleringen och simuleringarna. Treolika lastfall kommer att simuleras i ANSYS Workbench. Det första lastfallet kallas "hoggingsom kommer utgöras av ett böjmoment längs de vertikala sidorna om modellen. Det andra lastfalletkallas slammingöch består av en vertikal kraft riktad uppåt längs modellens undersida. Slutligen, består det sista lastfallet av en kraft på respektive vertikala sida längs modellen som ska ge upphovtill en vridning på modellen. I samtliga lastfall gav den befintliga fönsterinstallationen upphov till störst töjningar längs innerkanterna på smygskarven (kanterna närmast fönsterglaset). I slamminglastfallet gav lösningsförslaget utan dubbel dämpningsmassa upphov till minst töjningar längs innerkanterna på smygskarven jämfört med övriga fönsterinstallationer. I hogging och vridning lastfallengav lösningsförslaget med dubbel dämpningsmassa upphov till minst töjningar längs innerkanterna på smygskarven. Även lösningsförslaget utan dämpningsmassa lyckades dämpa töjningarna längs innerkanternapå smygskarven jämfört med den befintliga fönsterinstallationen. Sammanfattningsvis har lösningsförslaget utan dubbel dämpningsmassa i helhet minskat töjningarna längs innerkanternapå smygskarven där de flesta läckor och sprickor har observerats. Framförallt har lösningsförslaget varit effektiv i slamming lastfallet. Även fast lösningsförslaget med dubbel dämpningsmassa bäst motstårhogging och vridning, är slamming lastfallet det mest förekommande lastfallet. Därför bör den fönsterinstallation som bäst dämpar töjningarna vid slamming prioriteras. Därav är lösningsförslagetutan dubbel dämpningsmassa det bästa alternativet då den är effektivast mot slamming samt att den reducerar töjningarna kring innerkanterna på smygskarven jämfört med befintliga fönsterinstallationeni resterande lastfall.

To be able to ensure range safety and quickly recover the rocket and any on-board experiment, it is essential to be able to track the rocket. For sounding rocket launches at Esrange, this is typically done with radar or rocket telemetry, it has, however, recentlybecome of interest to do so with an optical system. This thesis develops the necessary methods for an optical system used to track and reconstruct the trajectory of a sounding rocket. It further discusses the limitations of such a system, given the hardware andinfrastructure available. Finally, some of the methods are tested with previous rocket footage showing that the suggested method works well for the available test cases. The full method uses foreground detection to detect the rocket in the image and using thisdata from multiple cameras combine to triangulate the 3D-coordinates of the rocket. A simple calibration method for the cameras is proposed, and future work to improve the capabilities of the system are proposed. The results show reliable tracking of the rocket,but raises concern in the viability of using current hardware for tracking the rocket during daytime due to difficulties in the visibility of the rocket in these conditions. The developed methods are foremost suggested to be used in nighttime conditions. / För att kunna säkerställa säkerheten vid en raketuppskjutning och för att snabbt kunna återhämta raketen och alla experiment ombord är det viktigt att kunna spåra raketen. För sondraketuppskjutningar vid Esrange görs detta vanligtvis med radarellerrakettelemetri, men det har nyligen blivit av intresse att göra det med ett optiskt system. Detta examensarbete utvecklar de nödvändiga metoderna för ett optiskt system som används för att spåra och rekonstruera banan för sondraketer uppskjutna av SSC. Den diskuterar vidare begränsningarna för ett sådant system,givet den tillgängliga hårdvaran och infrastrukturen. Slutligen testas några av de metoder som utvecklats med tillgängliga testdata. Metoden som utvecklats använder förgrundsdetektering för att upptäcka raketen i bilden och använderdenna data från flera kameror för triangulering av raketens 3D-koordinater. En enkel kalibreringsmetod för kamerorna föreslås och framtida arbete för att förbättra systemets kapacitet föreslås. Resultaten visar pålitlig spårning av raket, men visaräven att nuvarande hårdvara troligtvis inte är tillräcklig för att spåra raket under dagtid. De utvecklade metoderna är huvudsakligen bäst ämnande för uppskjutningar på natten.

There are many applications where 3D models of landscapes can be used, suchas determining volume of objects, inspecting buildings and planning of infrastructure.One common way of creating 3D models of a geographical area is totake overlapping geotagged photos with a drone and then perform an aerotriangulation(AT). The aerotriangulating software find common key points in theimages and create a 3D surface model of the area. This process requires the use ofground control points (GCPs), which are used to map the 3D model onto a globalcoordinate system. These GCPs consume a lot of time to place at the location,measure accurately with total station and manually pinpoint in several photos.The purpose of this study is to compare models created by images taken with differentGNSS-based drone positioning systems and investigate for example howmany GCPs are needed, how the GCPs should be placed, and how the accuracyof models vary between the drone positioning systems considering both relativeand absolute accuracy.Two data acquisition sessions were done where images from two differentlocations were collected. In the first session the use of regular GPS and the use ofa local reference station are used as positioning system for the drone, and in thesecond session network real time kinematics (RTK) is also used as a third kind ofpositioning system.From the produced 3D models there is no significant difference between modelsusing a local reference station and network RTK, but when only using GPS thevertical accuracy drops significantly which means that more GCPs are required inorder for the model to be accurate. The standard deviation for points in createdmodels is calculated in easting, northing and vertical for the coordinate differencesfor the three positioning methods. When no GCPs are used the absoluteaccuracy is drastically lowered to meter level accuracy. In conclusion, by usingnetwork RTK or a local reference station the same accuracy for the 3D model canbe acquired with much fewer GCPs than if stand-alone GPS is used. None ofthe positioning systems can fully replace GCPs when a high absolute accuracy isneeded. With a relative accuracy requirement of 10 cm or more, both networkRTK and use of a local reference station has the potential to provide such qualitythat a 3D model would not need GCPs. / Det finns många tillämpningar där 3D-modeller av geografiska områden används,till exempel att bestämma volym av föremål, inspektera byggnader ochplanera infrastruktur. Ett vanligt sätt att skapa 3D-modeller av ett geografisktområde är att ta överlappande geotaggade foton med en drönare och sedan utföraen aerotriangulering (AT). Under en AT lokaliserar programvaran gemensammanyckelpunkter i bilderna och skapar en 3D-modell av området. Denna processkräver användning av markstöd som används för att passa in 3D-modellen i ettglobalt koordinatsystem. Markstöden tar mycket tid att placera i i området, fastställaexakt position med totalstation och manuellt precisera i flera foton. Syftetmed denna studie är att jämföra modeller skapade av bilder tagna med olikaGNSS-baserade drönarpositioneringssystem och undersöka till exempel hur mångamarkstöd som behövs, hur markstöd ska placeras och hur modellernas noggrannhetvarierar mellan drönarpositioneringssystemen i avseende på relativ och absolutnoggrannhet.Två fältundersökningar genomfördes där bilder från två olika platser samladesin. Under den första fältundersökningen användes vanlig GPS samt enlokal referensstation som positioneringssystem för drönaren, och i den andra fältundersökningenanvändes även nätverks-RTK som en tredje typ av positioneringssystem.Det är ingen signifikant skillnad mellan modeller producerade utifrån datafrån en lokal referensstation och nätverks-RTK, men när man bara använder GPSsjunker den vertikala noggrannheten avsevärt vilket innebär att fler markstödkrävs för att modellen ska bli noggrann. Standardavvikelsen för punkter i deolika modellerna beräknas i östlig, nordlig och vertikal riktning för koordinatdifferenserför de tre positioneringsmetoderna. När inga markstöd används sänksden absoluta noggrannheten drastiskt till meternivå. Sammanfattningsvis, genomatt använda nätverks-RTK eller en lokal referensstation kan samma noggrannhetuppnås för 3D-modellen med färre markstöd än om endast GPS används. Ingetav positioneringssystemen kan helt ersätta markstöd när en hög absolut noggrannhetbehövs. Med ett relativt noggrannhetskrav på 10 cm eller mer har bådenätverks-RTK och en lokal referensstation potentialen att tillhandahålla sådankvalitet att en 3D-modell inte skulle behöva markstöd.

Martian Moons eXploration is a JAXA-lead mission aiming at exploring the moons of Mars, Phobos and Deimos. The hyperspectral infrared camera provided by France should perform global mapping of Phobos at high resolution in order to characterize surface composition and therefore help determine the origins of the moons. Based on 3D scenes and radiance modeling, a physical simulator is implemented to render images without aliasing. Satellite position and attitude on quasi-static orbits as well as solar ephemeris and expected Phobos surface properties are given as entries. Thanks to the combination of geometry and radiometry simulations, hyperspectral cubes representative of the acquisitions from a matrix sensor are computed. Future prospects include the adaptation of the simulator to different instrument concepts and Earth-observation contexts. / Martian Moons eXploration är ett JAXA-lett rymduppdrag som syftar till att utforska Mars två månar, Phobos och Deimos. En hyperspektral infraröd kamera utvecklad i Frankrike ska utföra en högupplöst global kartläggning av Phobos som senare ska kunna hjälpa till att analysera månens ytegenskaper i försök att fastställa dess ursprung. Baserat på 3D bilder och strålningsmodellering kommer en fysiksimulator att rendera bilder utan vikningsdistorsioner. Indata till simulatorn är satellitpositionen, styrning av kvasistatiska omloppsbanor, bandata från solen samt Phobos ytegenskaper. Hyperspektrala kuber kommer att beräknas baserat på en kombination av geometri och radiometri. Dessa representerar den uppsamlade datan från optiska matrissensorer. Framtida möjligheter och studier inkluderar bland annat anpassningen av simulatorn till olika vetenskapliga instrument samt fjärranalys av jorden.

Vibration causes problems in many kinds of machinery including fighter aircraft. It can, for example, cause structural fatigue, malfunction in equipment and injuries to humans. The sources of vibration are engines, flow disturbance and separation of external loads, to mention some. To isolate sensitive equipment from the source of vibration it is common to use vibration isolators made of rubber. This master’s thesis is performed at Saab Aeronautics in Linköping at the Department of Environmental Engineering & Thermal Analysis. The subject of the master’s thesis is to develop a methodology for the analysis of vibration isolating systems in aircraft. The work is performed by finite element analysis and laboratory tests using a shaker table. In the finite element analysis, part of the study, a method to condensate the structure to decrease the number of degrees of freedom is studied and used. Nonlinearities are investigated but only linear characteristics are implemented into the f inite element model. Rubber as a material has several non-linear characteristics that depend on the amplitude and frequency of the vibration. For example, the stiffness and damping are amplitude dependent. From laboratory results from tests on a shaker table, the stiffness and damping of the vibration isolators are extracted. To do this, the frequency transfer function is used by identifying eigenmodes and the eigenfrequency to calculate the stiffness and extract the damping by studying the shape of the peak. A finite element model with a condensed structure is used to find the eigenmodes and the eigenfrequencies. By exciting the finite element model the frequency response is also calculated. The tested vibration isolator shows large non-linearity for the stiffness and damping when varying the amplitude of a sinusoidal vibration. Using a condensed structure in finite element is a powerful tool to reduce computational time. If the solution of a simulation or calculation has to be very accurate or if the amplitudes of the vibration vary a lot, the non-linearities must be implemented into the simulation or calculation and accounted for.

Space travelling within the solar system is expected to expand within the upcoming years, with the Moon and Mars as main targets. These longer space flights results in longer time periods within a complex radiation environment for the astronauts. Dose limits therefore have to be established by space agencies for their respective space workers, to secure maximum safety and as low risks as possible. A radiation model is constructed by many building blocks, ranging from radiobiology to physics. The state of the art of the current models are described in this paper, followed by the uncertainties and knowledge gaps related to the respective space agency’s approach. These mainly include more extensive research of the available data for exposed populations, adapting the inputs to the relevant population, and the choice of risk quantity and track structure models. By focusing on the largest uncertainty contributors, Europe can add importance to this essential research and form a European space radiation model for European space workers.

Long term settlement on different planets of the solar system is a fascination for mankind. Some researchers contemplate that planetary settlement is a necessity for the survival of the human race over millions of years. The generation of food for self sufficiency in space or on planetary bases is a vital part of this vision of space habitation. The amount of mass that can be transported in deep space missions is constrained by the launcher capability and its costs. The space community has proposed and designed various greenhouse modules to cater to human culinary requirements and act as part of life support systems. A survey of the different greenhouse space concepts and terrestrial test facilities is presented, drawing a list of measurable factors (e.g. growth area, power consumption, human activity index) for the evaluation of greenhouse modules. These factors include tangible and intangible parameters that have been used in the development of an evaluation method on greenhouse concepts as a subsystem of planetary habitats at the DLR Institute of Space Systems, Bremen. / <p>Validerat; 20121003 (anonymous)</p>

Multiengine first stages are the new trend in recent rockets. Reusability and an oxygen/methane based engine complete this picture. ArianeGroup wants to develop its own rocket following these principles. This thesis presents the study of the feeding system for a seven Prometheus engine rocket. Several ways of connecting propellant tanks to engines were proposed and analyzed. Two configurations were selected and studied with more detail. One consists of a main feeding line which is then split in seven secondary lines. The other one adds one rank of pipes to reduce the number of feeding valves. Their performances were assessed according to classic space industry drivers. Furthermore, the impact of the two solutions on the efficiency of the tank was evaluated. CAD drawings and simulation models were made and could be a base for future work if one of the systems is chosen. The study shows that a falcon 9 like feeding system is performant in terms of mass and pressure losses but another cost-effective configuration is possible and gives good results. / Första stegen med flera motorer är den nya trenden i de senaste raketerna. Återanvändbart och en syre och metan-baserad motor kompletterar denna bild. ArianeGroup vill utveckla sin egen raket enligt dessa principer. Denna avhandling presenterar studien av drivmedelsrör för en sju Prometheus-motorraket. Flera sätt att ansluta drivmedelstankar till motorer föreslogs och analyserades. Två konfigurationer valdes ut och studerades mer detaljerat. En består av en huvudlinje som sedan delas upp i sju sekundära linjer som på SpaceX Falcon 9. Den andra lösningen lägger till en rang av rör för att minska antalet ventiler. Deras prestanda utvärderades först enligt klassiska kriterier för rymdindustrin. Dessutom utvärderades de två lösningarnas påverkan på tankens effektivitet. CAD-ritningar och simuleringsmodeller gjordes och kan vara en bas för framtida arbeten om ett av systemen väljs. Studien visar att ett Falcon 9-liknande konfiguration har bättre prestanda när det gäller massa och tryckförluster men en annan kostnadseffektiv konfiguration är möjlig och ger goda resultat.

The landing procedure of an aircraft is a safety critical procedure requiring high precisioncontrol and feasible trajectories to follow from the current state. This thesis implementsand studies a complete system with trajectory planning, trajectory following, and steeringcommand generation. Dubin’s path is the method implemented for the feasibility ofthe planned trajectory, with the extended implementation of variable speed and verticalmovement. It is important to reach but not exceed the aircraft limitations and considerthe control signals’ physical boundaries. A Model Predictive Controller is implementedto abide by constraints and preferences on the states and control signal. The systemsuccessfully generates and follows the planned trajectory with the models established inthis thesis. The resulting steering command from the created system would be moreintuitive for the pilot than the currently used approach, but it can not conclude whetherthe simulated results are a true indication of functionality, further tests in a more extensivesimulation environment are needed for a definitive answer.

The space sector has been evolving due to the fast-technological advancements generating a reduction of manufacturing, cost and size in space missions, where highly capable performing small satellites are becoming the standard in this industry. Furthermore, the high launching cost limits the trend of cost reduction for the space missions, since the small satellites are sent as a second payload. An alternative to reduce this limitation is using reusable launchers which are key in the future of space industry, once they are optimized in efficiency and reliability. Therefore, an opportunity of design is presented, since the increase of small satellites missions requires a reduction of the cost in launch services a suitable option for the future market are the reusable launchers. The problematic of using recovery systems and reuse parts of the vehicle is the increase of weight due to the added systems that the vehicle needs to be recovered. This paper presents different engines and calculate the performance of each engine based on the needs of missions for small satellites. The starting conditions will be that the payload needs to be launched in low circular or elliptical orbits (altitudes of between 300 and 650 km) and the engine has the ability of vertical take-off, vertical landing. The design will also take into account the possibility of reusing parts of the vehicle and the reentry capability. Different combination of engines and fuels are setup in various configurations. For each case the mass analysis will be developed which will allow to calculate the performance for each engine. The important parameters are the number and type of engines, the ratios of the masses, the thrust-to-weight ratio and specific impulse. Once the mass analysis is obtained the following procedure is the selection of the design considering the empty mass. The best combination of characteristics of the engines will be the suitable candidate. Different assistance systems and techniques for the recovery are assessed to obtain a suitable option to improve the efficiency. The expected results are the calculation of the engine performance and how the selected design can be suitable for the space launcher sector for the small satellites. The expected results are a feasible vehicle for small satellites design based in the calculation of the engine parameters together with an efficient launch recovery system. The conclusion is that the space sector can benefit from the design, demonstrating that a launch vehicle with the reusable characteristics.