EUSO-Balloon and EUSO-SPB are balloon borne pathfinder projects designed to val- idate the techniques of the JEM-EUSO space observatory. They are nadir pointing UV telescopes that use experimental experimental Fresnel optics to detect the ultravi- olet emission of Extensive Air Showers (EAS) induced by Ultra High Energy Cosmic Rays (UHECR) in the atmosphere. EUSO-Balloon was launched by the balloon di- vision of CNES (the french space agency) from Timmins, Ontario, Canada in 2014. Despite the success of the mission the performance of the optics was lower than what it was originally modeled and led to many doubts regarding the understanding of the optics and fresnel lenses themselves. This thesis explores three parameters proposed to explain the reduction in eciency of the system which were not simulated in the original characterization: the rounded valleys in the Fresnel lens grooves created by the tool peak radii, scratches on the surface of the lenses and the surface roughness of the fresnel lenses. These parameters were simulated and results show that they show a reduction in performance which approximates more the characterization measure- ments but still do not match exactly, leaving room for further analysis. EUSO-SPB1 is the successor of EUSO-Balloon with a launch planned in 2017 from Wanaka, New Zealand. The results of the first phase of the optics characterization campaign is pre- sented in this work. The results indicate that the optics performance is similar to that of EUSO-Balloon and require further understanding. / <p>Thesis defended in Toulouse, France as part of the SPACEMASTER programme.</p>

Gas turbine performance models are usually created in an object oriented manner, where different standard components are connected to form the complete model. The characteristics of these components are often represented by component maps and empirical correlations. However, engine specific component characteristics are seldom available to anyone outside of the manufacturers. It is therefore very common for researchers to use publicly accessible or generic component maps instead. But in order to reduce prediction errors the maps have to be modified to fit any specific engine. This thesis work investigates the process of adapting a parametric turbofan engine model to a limited amount of test-data using the propulsion program EVA. Steady state test-data was generated using an initial reference model with SLS operating conditions. Another engine model with different fan, compressor and turbine maps was then used in the adaptation. An initial on-design model was adapted to the highest power test-data point. This model is based on aerothermodynamic equations and is used as a reference to scale the generic component maps to. A sensitivity analysis was done at this point in order to find dependencies between unknown component parameters and test data. These were then included in the cycle solver which employs a version of the Newton-Raphson method. After the fan and compressor maps had been scaled to the design point they were adapted to test-data by adjusting the mass flow parameters in a direct search optimizer. Finally, speed lines in the fan and compressor maps were relabeled to reduce rotor speed errors. The adapted performance model was then validated against the reference model at a few flying conditions. The performance model results demonstrate that it is possible to greatly reduce prediction errors by only adjusting the corrected mass flow in fan and compressor maps. Additionally, rotor speed errors could successfully be corrected as a final step in the adaptation by relabeling speed lines in the component maps. When validated, the adapted model had a maximum parameter error of 1.5%.

Gravitational Waves (GWs) are ripples in the curvature of spacetime that propagate as waves at the speed of light while travelling basically undisturbed from the moment of their creation by accelerated masses. GWs provide unique information about astrophysical sources, such as binary systems, allowing their exploration under a wide range of masses, mass ratios and physical states inaccessible otherwise and therefore opening a new window to observe the universe. The Laser Interferometry Space Antenna (LISA) mission will be a spaceborne gravitational wave observatory that is expected to be launched in 2034. The observatory will operate a near-equilateral triangle constellation of three spacecraft in formation flying around the Sun with Earth-like orbits. The observatory will establish, for the first time, a huge laser interferometer of three arms separated by 2.5 million km at pm/ p H z sensitivity, allowing detection of GW signals in the low-frequencies (mHz) regime. Using technology proven by LISA Pathfinder and GRACE-Follow on mission, the LISA metrology system will continuously operate heterodyne laser interferometers in order to measure the stretching and squeezing of space-time coupled onto their laser links as pm-level pathlength displacements and recorded as tiny µ-cycle phase fluctuations over thousands of seconds by an on-board instrument so-called Phase Measurement System (PMS) or shortly "Phasemeter”. This master thesis investigates the thermo-mechanical design of an engineering model, currently under early phases of development, for the PMS instrument onboard the LISA S/C. The mechanical enclosure has been designed following a modular approach. Each PCB will be assembled into an individual enclosure, so future upgrades in the design without affecting the entire architecture. The thermal analysis conducted so far has concluded with the feasibility of a passive thermal management system in vacuum environments, based on heat conductivity throughout the mechanical enclosure towards the instrument baseplate. In particular, the following instrument features have been included within the analysis: 1. analog signal conditioning electronics, 2. analog-to-digital conversion, and 3. FPGA core signal processing, 4. high-phase fidelity frequency synthesis and 5. frequency distribution chain, i.e., all features with the most stringent thermal requirements of the PMS-EM architecture. Although the high-power consumption demands of the instrument, the proposed thermo-mechanical design showed a suitable implementation for reliable operation of components, below maximal specified temperature ranges, allowing safe operation of the electronics over mission lifetime. As the proposed design relies only on passive conductive heat transfer methods, it is implicit a reduction of instrument complexity, avoiding complex thermal approaches based on heat pipes distributions or active control systems. Moreover, the modular approach and thermal management system enhances the integration with adjacent modules and reduce cost when assembly the instrument within the payload. In this master thesis, it has been also designed and manufactured several mechanical enclosures, together with an active thermal management system, for preliminary prototyping of analog signal acquisition electronics. These prototypes have been tested in air, setting the thermal stability requirement at the thermal reference point (TRP). Test results have verified a thermal stability requirement below 0.1 K/Hz in order to accomplish with the stringent µ-cycle phase noise performance in the mHz frequency band. Further work will test those prototypes in Vacuum conditions, consolidating thermal modelling and noise coupling as initial precursors of the PMS-EM thermally critical module developments.

With growing awareness and necessity for the world to move towards more sustainable (energy saving) forms of power generation, focus on the commercial use of Organic Rankine Cycle (ORC) turbine systems has subsequently increased in turn. ORC systems with their modular design can thus help in recovering heat, obtained as a byproduct from a variety of industrial processes, and thereby increase their overall system efficiency. As with conventional turbine systems, methods to improve their performance is an avenue that is still being actively researched on today. The various sources of losses in a turbine have thus been looked into, while prioritizing the literature study to factors that result in losses associated with the leakage flow over the blade tip. The purpose of this study is to develop a working methodology to investigate factors that affect the tip leakage loss in a small scale ORC turbine. The model and associated data used for comparison is based on an existing system, whose design has been provided by Againity AB, with the subsequent simulations carried out using Ansys CFX.

The SherpaTT rover is prepared for further autonomous long distance traverses in terrain akin to the Martian environment. However, it features a fueled power generator which cannot be employed in extra-terrestial scenarios. As the rover is meant to approach a higher technology readiness level, a photovoltaic power subsystem is proposed to guide future design iterations. This thesis presents the solar array sizing, design, and integration processes considered for two Martian mission sites: Iani Chaos at 2°S and Ismenius Cavus at 34°N. An alternative use case for the active suspension system is presented so that the proposed solar arrays may be inclined and oriented into power generating configurations that are more favorable than those achieved with passive suspension rovers. This results in traverse gains of up to 34% and 25% for clear days at Iani Chaos and Ismenius Cavus, respectively.

In this thesis, theoretical studies are conducted to see whether plasma will detach from the magnetic field lines of the VASIMR thruster, and if so, at which location detachment takes place. A magnetic field similar to the field of the VASIMR VF-24 engine [1] is used and ions of different speed and massare sent from various radial positions in the exhaust. Calculation with different values of the anomalous resistivity parameter ωτ is conducted and the sensitivity to this parameter is studied. The validity of the method is studied by comparing results to previous work by Carl Wesslén [2]. From the results it is concluded that using heavy ions sent at high speeds will achieve detachment and high thrust efficiency, even when assuming relatively high values of ωτ. Ejecting ions at a slower pace or using lighter ions will make the engine less efficient, requiring low ωτ which is difficult to achieve. For some combinations of mass and speed, detachment is not possible at all. Ions with heavy mass are recommended to use as propellant for this type of thruster.

The conventional tube-and-wing aircraft has been around since the 1950s, with little to no innovative progress being made towards redesigning the conventional aircraft. The blended wing body (BWB) shape fuses the wing of the aircraft with the fuselage increasing structural strength while also increasing potential surface area to create lift, making it more efficient than conventional wing shapes. Today aviation has a 2 % CO2 contribution to global emissions. Aircraft manufacturers are predicting a steady rise for the aviation industry. The contribution of green-house gases is set to increase exponentially. Hydrogen fuel cells could deem a good fit between traditional combustion engine aircraft and electrical aircraft having a high efficiency but also being fuel-based. This report investigates the possibility of a prototype model of the Project ''Green Raven'' from KTH of creating a hybrid fuel cell BWB UAV with a 4 m wingspan. The analytical data is from literature and available benchmark data. First, an electrically driven subscale prototype is made and tested, and then the full-scale model is made. The prototype is pro-posed to be driven by a single two-bladed propeller with 10 x 4.7-inch dimensions running at 10000-13000 rpm with a takeoff weight of 4 kg, where 0.75 kg of the weight was from 5 Li-Po batteries. Performance parameters were calculated by given data with a given cruise speed of 30 m/s and a cruise endurance of 1 hour. The prototype will fly for close to maximum load at climb with an angle of 6°. With the Li-Po batteries with a total of 11 Ah, the aircraft has more than 10 % to spare for safety reasons.

The thermal design of small satellite missions is critical for ensuring the performance and longevity of onboard instruments. This thesis focuses on the thermal design of Foresail-2, a 6U CubeSat mission to Geostationary Transfer Orbit (GTO), specifically addressing the thermal challenges associated with the magnetometer located at the end of a long boom featured on the satellite. The objective of this research is to estimate the orbital loads, study its effects and develop an effective thermal control strategy to maintain the frame, boom and magnetometer temperature within an optimal operational range throughout the mission duration. A steady state thermal analysis is conducted to evaluate the effects of the GTO environment on the satellite structure under different operational scenarios and design conditions. To achieve the desired thermal control, several potential regulation strategies are investigated, including passive thermal coatings, insulation materials, and active cooling methods. Furthermore, thermal simulations are performed to predict the temperature profiles and gradients within the boom and magnetometer assembly, enabling the identification of potential hotspots or areas prone to thermal stress using ANSYS software package. These findings contribute to the implementation of thermal design modifications and the optimization of the configuration of the boom and magnetometer to enhance thermal performance. The results of this thesis contribute to the development of a robust thermal design for Foresail-2 mission satellite. Moreover, the methodologies and insights gained from this research can be extended to other CubeSat missions with similar thermal requirements and constraints.

Electromagnetic compatibility (EMC) is a very important and increasingly relevant technology in use and is closely related to many technologies such as automobiles and aerospace industry technology including aircraft and spacecraft. Achieving electromagnetic compatibility between equipment inside the device is more than necessary to avoid the problem of interference leading to serious problems. More than that, achieving electromagnetic compatibility for the device as a complete system is quite challenging. The device as a whole system is necessary to be compatible with its electromagnetic environment in order to avoid the problem of interference with other devices which also leads to safety issues. The objective of the thesis is to measure EMC radiated emission from the aircraft as a complete system and to know its compatibility with its electromagnetic environment, by building knowledge of the challenges that arise when conducting electromagnetic compatibility measurements of the aircraft as a whole system outside a protected environment. The challenge here is that there are no standards for EMC radiated emission of the aircraft as a complete system in an Open Area Test Site (OATS). This required us to research and try to relate what was done in this field to try to plan to build an OATS to conduct EMC radiated emission on aircraft as a whole system. We have come up with, that the measurement of EMC radiated emissions performed on the aircraft as a complete system in an OATS at Skellefteå Airport, shows similar results to those obtained on Aircraft SIMulator (ASIM) tested in a Fully Anechoic Chamber (FAC). In addition, we performed a civil airport of Skellefteå site validation measurement and obtained the result that the site complies with the OATS requirements in CISPR 16-1-4: 2019 standard. This work is considered a building block for other EMC studies in the field of space technology, which calls for the need to think about achieving electromagnetic compatibility to avoid all that results from electromagnetic interference (EMI) on the safety of pilots, astronauts, and all human life.

The tip leakage vortex is responsible for the generation of stagnation pressure losses inside the compressor along with the outbreak of rotating stall and surge. The current paper analytically proved that a part of the losses is proportional to the vortex circulation squared. The evolution of this circulation has been investigated as part of a parametric study which tested several clearance heights. The work consists in adopting a simplified single blade configuration to study the physics of the flow by means of wind tunnel experiments and numerical calculations. Upon visualising the main features of the flow, a model based on the study of jet in crossflows was implemented to describe the tip clearance flow for small gap sizes. For big gaps, the flow is assumed to behave as an isolated wing tip vortex which circulation is easily computed by the so called lifting line theory. The main vortical structures highlighted by the topology of the flow justified the use of the model of a jet in crossflow for small gap sizes. This model was challenged by experimental and numerical data and proved to well predict the evolution of the clearance vortex circulation for an increasing clearance height although some numerical results remain further away from the model. / Gapvirveln är ansvarig för lufttryckförluster i motorn av ett flygplan och kan orsaka utbrottet av kompressorstall och pumpning. Artikeln bevisade matematiskt att en del av de här förlusterna är proportionell mot gapvirvelncirkulationen upphöjd. Utvecklingen av den där cirkulationen undersöktes med hjälp av en parametrisk studie som provkörde flera gapstorlekar. Arbetet bestå av att adoptera en förenklad enda blad konfiguration för att studera flödes fysik med vindtunnel experiment och flödesberäkningar. Efter att man analyserar flödes viktigaste egenskaper genomfördes en modell baserad på studien av en jet i ett korsflöde. Den här modellen används för att beskriva flödet för små gapstorlekar. För stora gap antar man att flödet beter sig som en vingspetsvirvel som cirkulationen kan beräknas utan svårighet med hjälp av lyftledningsteorin. Flödes topologi visualiserades tack vare numeriska beräkningar och legitimerade användningen av modellen av en jet i ett korsflöde för små gapstorlekar. Teoretiska, experimentella och numeriska resultat jämfördes och bevisade att modellen väl förutsäger utvecklingen av gapvirvelncirkulationen mot gapstorlek även om några numeriska resultat är långt från modellen.