The Floating Satellite (FloatSat) system project which has been developed at the ‘Department of Aerospace Information Technology - University of Würzburg’ is used to test, develop and implement various attitude control algorithms and strategies for small satellites [1]. The FloatSat project is designed to operate on a Frictionless air bearing surface that works with compressed air flowing distributed on a hemisphere. This hemisphere is used to replicate the space environment required for a satellite to perform its attitude control, solar panel deployment and payload mission, the FloatSat basically consist of 1 axis control and stabilization with reaction wheel. Taking FloatSat to the next level, the aim of the Thesis is to Design, Fabricate and Model a three-axis controllable FloatSat that can be contained in a Sphere for free rotation and movement. The best feature of FloatSat is that they are plug & play, easily accessible and compact size; retaining all these features in the design and extending the functionality of the product proves to be challenging. Furthermore, in the thesis it will be explained in detail about the various design consideration and selection of most feasible method on producing the final product. After the preliminary research for the design characteristics it was clear that the new FloatSat will be equipped with a controllable center of gravity mechanism that will provide balancing in any desired orientation. To obtain this feature three controllable moving masses are to be used in each axis of reaction wheel position. With Three reaction wheels and three moving masses to be equipped in the FloatSat the design challenges were high as considering the Sphere diameter is only 198mm. The various successful 3 axis satellite simulators are either huge or they are constrained in any one of the axis where it is positioned. On doing literature research it became clear that the sphere configuration with the given size has never been documented with promising results. It makes this thesis work to be first of its kind to perform 3 Axis FloatSat stabilization in a sphere of 198mm diameter. The FloatSat components include microcontroller STM32F4, Wi-Fi module for communication, three reaction wheel motors, three axial moving mass motor, Lithium Polymer batteries and motor controllers.

Detta arbete berör den grafiska presentationen av antikollisionssystemet TCAS. TCAS är ett oberoende system som används för att piloten ska ha en bra översyn om trafiksituationen runt om sitt egna flygplan och vid ett farligt närmande få manöverrådgivningar för att undvika kollision. För piloten presenteras TCAS på en trafikdisplay som ofta är integrerad i någon annan display såsom navigationsdisplayen. Vid manöverrådgivning får man rådgivningar på en RAdisplay som ofta är integrerad i PFD.  Syftet med detta arbete är att se om det går att förbättra den grafiska presentationen som piloten får, då det har visat sig att förståelsen för systemet ibland är bristande och vid hög trafikdensitet kan det bli rätt rörigt på trafikdisplayen. Detta är viktigt då piloten måste ha en bra uppfattning om trafiksituationen och kunna vara beredd på att göra en undanmanöver. Det är även viktigt att systemet är simpelt samtidigt som den ger all nödvändig information för att piloten ska vara medveten om trafiksituationen.   Jag har i detta arbete utvecklat nya symboler genom att titta på riktlinjer för symboldesign. Symbolerna utvecklades med hänsyn till mänskliga faktorer och hur människan reagerar på olika faktorer i symbolen, som till exempel färg, uppmärksamhetsfaktorer och form. Det befintliga systemet testades i en flygsimulator. Detta gav en bra praktisk bild av hur systemet ser ut idag, och även en ide om hur jag ska utveckla de nya symbolerna.    En intervju gjordes bland 6 kommersiella piloter, och utifrån deras feedback fick jag en förståelse för vad de ville ha för information på trafikdisplayen och vad de tyckte om det system jag utvecklat. Modifieringar gjordes och som resultat fick jag en simpel, men ändå informativ symboluppsättning.  Den nya presentationen gav i överlag ett positivt intryck, trots att de piloter som blev intervjuade sa att de skulle kunna använda den nya designen, var de nöjda med det befintliga systemet. De tyckte dock att den nya designen kunde vara bra vid utbildning.

Prediction of thermal loads within cavities in space turbine, has as been a challenging task  in aspects of achieving accurate and reasonable estimations that are crucial for design concepts. The difficulty lies within the turbulent flow and its thermal interaction with the structure inside such section. It does not exist a method that works perfectly for prediction of thermal loads in any cavity and the taken approach to perform this kind of analysis has been differently chosen. The objectives of this work have been to improve methods for assessment of thermal loads in space turbines, especially calculation of the heat transfer coefficient and bulk temperature. As the thesis was conducted at GKN Aerospace Sweden, Trollhättan, one of theirs demonstrator turbine was chosen for the study case. Its first stage rotor blade and the nearby cavity were the main research regions. The flow can enter and exit the cavity through one slot and is characterized with a very low axial speed. For the studied regions, the wall surface has been subdivided into a number of segments. With prescribed wall temperatures and use of computational fluid dynamics (CFD) to compute the wall heat flux at the sections, the heat transfer coefficient and bulk temperatures were determined in three different ways. One of them was based on evaluating one single CFD result and derive the thermal loads from formulas. The others used by point-plotting approach, whereas one of them focused on formulating a model that describes the thermal interaction between the section walls. The results demonstrate that this model was able to predict a section's wall heat flux as a function of the wall temperatures in fair agreement with CFD results for a range of temperature variations. Further more, some of the predicted heat transfer coefficient at a section shows to be highly sensitive to the prescribed wall temperatures in the cavity and rotor blade.

No description available.

The Space Variable Objects Monitor (SVOM) is a future French-Chinese satellite mission which is dedicated to the observation and characterisation of Gamma Ray Bursts (GRBs). When a GRB is detected by the satellite, the position and initial characterisation data are transmitted to ground via a VHF telemetry link, in order to trigger immediate follow-up observations of the transient GRB afterglow by ground-based telescopes. To optimise the prioritisation of this telemetry flow in various scenarios, detailed simulations of the VHF telemetry are required. In this thesis, a new telemetry simulator was thus developed: the MXT VHF Data Simulator. This simulator generates all VHF messages of the Micro X-ray Channel Telescope (MXT) instrument that would be expected during a typical operational scenario.  Each message is constructed byte by byte, with the required data formats, encodings and packet structures as specified by the SVOM telemetry standards and the MXT VHF TM specification database. To generate the scientific packet contents several approaches were combined. An existing camera frame simulator, developed at the LAL institute, was modified to simulate raw photon data for the given scenario, generating a set of binary camera frame files which is then parsed and integrated by the MXT VHF Data Simulator. MXT instrument scientists provided an example GRB profile with the temporal evolution of certain GRB parameters. In addition, several parameters were simulated manually, with an effort to achieve as realistic contents as reasonably possible, and in coordination and discussion with the MXT instrument scientists and software engineers. The output of the simulation consists of a set of MXT VHF telemetry files in binary and CSV formats. To verify the correct formatting and contents of the data, the files were validated using the internal CNES telemetry analysis framework PrestoTools. This analysis confirmed correct formatting and encodings in accordance with the telemetry specifications, as well as the expected data in the packet contents. Finally, the resulting data was integrated into the CNES VHF Simulator, and an analysis of a full VHF telemetry scenario with all four instruments was performed for the Data Challenge 1 (DC1) systems test scenario.

Downscaled physical models, also referred to as subscale models, have played an essential role in the investigation of the complex physics of flight until the recent disruption of numerical simulation. Despite the fact that improvements in computational methods are slowly pushing experimental techniques towards a secondary role as verification or calibration tools, real-world testing of physical prototypes still provides an unmatched confidence. Physical models are very effective at revealing issues that are sometimes not correctly identified in the virtual domain, and hence can be a valuable complement to other design tools. But traditional wind-tunnel testing cannot always meet all of the requirements of modern aeronautical research and development. It is nowadays too expensive to use these scarce facilities to explore different design iterations during the initial stages of aircraft development, or to experiment with new and immature technologies. Testing of free-flight subscale models, referred to as Subscale Flight Testing (SFT), could offer an affordable and low-risk alternative for complementing conventional techniques with both qualitative and quantitative information. The miniaturisation of mechatronic systems, the advances in rapid-prototyping techniques and power storage, as well as new manufacturing methods, currently enable the development of sophisticated test objects at scales that were impractical some decades ago. Moreover, the recent boom in the commercial drone industry has driven a quick development of specialised electronics and sensors, which offer nowadays surprising capabilities at competitive prices. These recent technological disruptions have significantly altered the cost-benefit function of SFT and it is necessary to re-evaluate its potential in the contemporary aircraft development context. This thesis aims to increase the comprehension and knowledge of the SFT method in order to define a practical framework for its use in aircraft design; focusing on low-cost, short-time solutions that don’t require more than a small organization and few resources. This objective is approached from a theoretical point of view by means of an analysis of the physical and practical limitations of the scaling laws; and from an empirical point of view by means of field experiments aimed at identifying practical needs for equipment, methods, and tools. A low-cost data acquisition system is developed and tested; a novel method for semi-automated flight testing in small airspaces is proposed; a set of tools for analysis and visualisation of flight data is presented; and it is also demonstrated that it is possible to explore and demonstrate new technology using SFT with a very limited amount of economic and human resources. All these, together with a theoretical review and contextualisation, contribute to increasing the comprehension and knowledge of the SFT method in general, and its potential applications in aircraft conceptual design in particular.

The following document describes an example mission, which originated from a real life concept of an imaging satellite in a Sun Synchronous Orbit (SSO)around Earth. This report takes the reader through the thermal analysis and evaluation of space equipment performed with Airbus Space & Defence’s Systema/Thermica tool, at Space Structures GmbH. It details the full process of designing a thermal control system for a space project. The project started from a CAD file which was converted into a Geometric Mathematical Model (GMM) inside Thermica. This process requires an extensive knowledge of not only the software, but also the technical background behind what happens to a satellite in such an extreme environment. This thesis addresses this by showing a step-by-step approach of a full thermal evaluation, starting with the required theoretical background of the thermal environment and the different passive and active thermal design techniques. The next step involves gathering the required input information for the software; such as defining the conductance values between the components and calculating the per node power dissipation for each component considering each operational mode. The final step includes the designing, simulation, iteration and presentation of the temperature results across the spacecraft thermal model. The results of the initial simulation showed that some sensitive components were not within the specified temperature requirements, and therefore both radiators and heaters were sized and introduced to the model. After the third iteration of thermal control, the sensitive components’ temperatures were observed to be within the allowable margins of an ECSS Phase A study. This thesis can serve as a guide and complete document for future missions which plan the design of a Thermal Control System of a satellite in orbit around Earth.

No description available.

Since the beginning of space exploration, the amount of space debris has increased with thedevelopment of new space technologies. In fact, when a collision happens, new space debris aregenerated. Hence, collision risk between space debris and operational satellites rises. The purpose ofa surveillance network system consists of the detection of space objects, their classification and theirtracking. To avoid collisions, space debris objects’ orbit must be computed with sufficient accuracy. The goal of this thesis is the improvement of a pre-existing Space Surveillance and Tracking AnalysisTool. The tool is able to simulate different observation scenarios for radar or optical observer,which can be space-based or ground-based. To enhance the orbit determination, an ExtendedSquare Root Information Filter is implemented and incremented with a Smoother. Smoothers havebeen implemented for the existing filters as well, such as the Extended Kalman Filter and theUnscented Kalman Filter. A bias estimation method was added as part of the OD for all filter types.Additionally, different outlier detection methods were implemented for the automatic detection ofoutliers within the measurement data. To find the optimum orbit determination interval, differentscenarios were considered in LEO, MEO and GEO orbits. The methods were implemented anddifferent scenarios for validation will be discussed. A wide discussion on the methods implementationand their validation on different scenarios is presented, together with a comparison of the orbitdetermination results with the other filters. All the recently implemented features increase the efficiency of the tool to simulate the differentscenarios and enhance the tracking of space debris objects.

No description available.