With the advent of Reusable Launch Vehicles (RLVs) on the European launch market, the German Aerospace Centre (DLR)’s In-Air Capturing (IAC) recovery technique promises a competitive reduction in launch costs. Central to this IAC procedure is the Aerodynamically Controlled Capturing Device (ACCD), which is deployed from a Towing Aircraft (TA) by means of a tether. It intercepts a returning RLV, and provides a structural interface between the TA and RLV during tow-back. Once in the vicinity of a landing site, the ACCD releases the towing connection, and the RLV lands autonomously. Whereas the aerodynamic shell of the ACCD has been defined and studied in the past, an in-depth exploration of its electromechanical design space has not been performed previously. This work proposes a systems engineering approach to fill the corresponding design gap, based on the definition of key requirements and risks characterizing the ACCD’s functionalities, and its operational environment.

First, the behaviour of the ACCD as part of a larger towing system is analysed. For this, a two-dimensional (2D), quasi-steady-state Towing Model is developed, enabling a swift exploration of the ACCD’s design space, as well as a preliminary estimation of extreme tow-back loads. This Towing Model shows that the ACCD’s towing position relative to the TA is highly sensitivity to the ACCD’s Centre of Gravity (CoG); in order to stay clear of the TA’s disturbing wake zone, a maximum allowable CoG position of 1 m behind the vehicle’s nose is defined. Additionally, a significant pitch control authority is demonstrated, indicating substantial manoeuvrability. Finally, a study of extreme tow-back conditions results in the definition of a 300 kN axial towing design load - representing a 72% increase compared to previous estimates.

Next, the ACCD’s relative navigation system is studied, used to estimate the position and attitude of the RLV. A comparison between state-of-the-art systems is made, and the so-called VisNav solution is proposed - with a sensor attached to the RLV, and active beacons mounted on the ACCD. In order to identify a representative configuration for this system, a geometric VisNav Model is developed, analysing the visibility of beacons from the sensor’s Point of View (PoV). Based on comparative studies performed with this model, a design with three asymmetric rings of twelve beacons is proposed. Combined with Global Navigation Satellite System (GNSS) and Inertial Navigation System (INS) data, this configuration enables relative position and attitude estimation with an accuracy of 20 cm and 1°.

A representative electromechanical design for the ACCD is then proposed, based on results from the foregoing design space exploration. On the one hand, the selection of Commercial-off-the-Shelf (COTS) avionics is covered, as well as a preliminary dimensioning of the vehicle’s power system. Here, the ACCD’s actuators are identified to be the main drivers of its electronic design in terms of Size, Weight and Power (SWaP) footprint. Additionally, the feasibility of a battery-powered design is demonstrated. On the other hand, a Computer-Aided Design (CAD) study of mechanical subassemblies is performed, which are further analysed in terms of extreme operational loads. Most noticeably, a separation of the docking and release systems is proposed, as combining both into a single mechanism is deemed infeasible, due to the continuous presence of significant towing loads. Based on the presented design, a Bill of Materials (BoM) for the ACCD is established, yielding a total functional mass of 159.14 kg. Because of the substantial impact of the vehicle’s wings and docking system on its overall CoG, an additional 16.3 kg trim mass is required to reach the desired CoG position. Compared to previous studies, the final estimate for the ACCD’s total mass has increased by 33%.

Concluding the study, compliance with the vast majority of the postulated design requirements is demonstrated, while a number of future improvements and complementary studies are identified. These include an aerodynamic redesign and shortening of the ACCD’s shell, to eliminate the need for a trim mass. Additionally, prototyping of this unique vehicle is highly recommended, in order to further study its behaviour, and validate the theoretical design proposed in this work.

There is a growing demand for nano-satellite missions that require advancements in micro-propulsion capabilities to facilitate a wider range of orbital maneuvers. Among these capabilities, the ability to accurately control thrust would unlock new possibilities for nano-satellite applications, including missions such as space debris removal and orbit transfer.
Delft University of Technology is currently pioneering the development of an innovative green propellant-driven micro-propulsion system based on micro-electro-mechanical (MEMS) technologies for its PocketQube, known as Delfi-PQ, which features a compact form factor of 5x5x5 cm. While the thruster itself is in development, the interfacing and integration with other components are still ongoing.
Given the stringent mass, volume, and power limitations imposed by PocketQube satellite requirements, there is a pressing need for micro-scale components to realize a highly integrated propulsion system.
This thesis focuses on the design of a MEMS-based microvalve for proportional flow control in micro-resistojets. The design is conceptualized as comprising three components working in harmony: a valve seat with inlet and outlet, a flexible membrane, and a piezoelectric actuator. The valve seat with inlet and outlet, as well as the flexible membrane, utilize MEMS manufacturing techniques and are based on a silicon chip. And, a new design for piezoelectric actuators employing the d31 mode for contraction strokes is proposed.
The proposed preliminary design is a normally closed microvalve designed for a flow rate of 5g/hr, with the flexibility to accommodate higher flow rates if needed. It offers proportional flow control, ensuring precise regulation of fluid flow. Additionally, it promises a low power consumption of less than 1W and a low response time. Furthermore, this thesis provides a detailed outline of the MEMS fabrication process flow available at TU Delft’s Else Kooi Laboratory for the device. It also features a comprehensive test plan aimed
at assessing the feasibility of this design in future studies. Additionally, the thesis includes an elaborate risk analysis to help identify and mitigate potential risks during the manufacturing and testing phases.
The design shows promise and could pave the way for future developments of the microvalve within the department.

With the price of launching satellites remaining high, many companies and universities are turning towards smaller satellites as more affordable options. This requires the miniaturisation of their different components, including the propulsion subsystem. At TU Delft, Vaporising Liquid Microthrusters (VLM) are being developed, with the latest iteration being a new generation Micro-Electromechanical System (MEMS) design. In this work, the updated design of this microthruster is remanufactured and prepared for future operational validation, heat transfer and instabilities studies. This is done by simplifying the manufacturing process, creating a testing interface, and performing measurements and extensive experimental characterisation of the thruster and test set-up. The newly-created interface allows for the study of heat transfer efficiency and convection heat transfer coefficient (HTC) from the silicon wall to the propellant, as well as multiple ways to study the instabilities in the system. One interface + thruster assembly was shown to survive to at least 180 °C temperature and 6-7 bar relative pressure. On the manufacturing side, the fabrication process was streamlined by reducing the number of steps by 13%, most significantly by the use of a soft photolithography mask instead of a hard silicon dioxide one. The deviations in horizontal dimensions are in the same order of magnitude as the ones obtained by the previous student working on this project, and lower than other previous attempts at the Faculty of Aerospace Engineering. The etching process encountered some difficulties, leading to inconsistencies in the feature depth between wafers. Across wafers, etching rate deviations as large as 8% were observed. Within the final production wafer, the range of deviation from the design values on throat depth was from +3.5% to −16.5%, showing a measurable higher etching rate at the edges of the wafer than in the centre. Recommendations were given on which features’ depths are most important to be measured, in order to increase the confidence in the predicted values. With these results, future researchers are ready to use the produced thrusters and testing interfaces. It is recommended to continue with the experimental studies, especially by measuring the heat transfer efficiency, thrust levels, HTC, and by studying any instabilities that could appear.

Inaccuracies in robotic arms can significantly hinder their performance in tasks where precision is critical. This thesis focuses on the kinematic calibration and elasticity compensation of a 6 degrees of freedom robotic arm integrated into the Lunar Rover Mini, developed in collaboration with the Robotics and Mechatronics Institute of the German Aerospace Center (DLR), Wessling. The arm, constructed using 3D-printed components and driven by affordable RC servo motors, experiences notable inaccuracies in end-effector positioning due to joint flexibility and structural deformation, especially under load. This research aims to enhance the arm's accuracy through a model-based calibration approach that compensates for both elastic deformations and geometric misalignments, addressing the absence of feedback sensors. This cost-effective approach, which requires only 3D measurements of the end-effector's position, has resulted in an approximately 80% reduction in the robotic arm's average position error, proving advanced robotic technologies can be more accessible for educational and research applications.

Ball valves are a critical component in a plethora of liquid propellant propulsion systems. The Spanish company PLD Space is considering the usage of these valves in their new series of KER-LOX liquid propellant rocket engines, the TEPREL-C & TEPREL-C Vacuum engines. These will be operating on-board the Miura 5 launch vehicle. The purpose of this research is to re-design and analyze an unoptimized ball valve design, as to make it suitable for cryogenic service while minimizing its mass. The secondary objective of the research is to inquire into the aspects of ball valve operation. This includes investigating the required operating torque of a ball valve and the achievable flow factor as a function of a ball valve's opening angle. The results of this thesis are scripts which can estimate the torque and flow factor values, a methodology to mass-optimize a ball valve, and a re-designed ball valve suitable for cryogenic service.

A laser-sustained plasma (LSP) generator capable of operating as a laser-thermal thruster was designed and tested. The apparatus was powered by a 3-kW 1070-nm fiber-optic laser and was operated with argon gas. The laser absorption, radiated spectrum, and change in static pressure were recorded, and high-speed video footage of the LSP was acquired. Of special interest is the heat-deposition efficiency into the working gas resulting from LSP ignition, which was estimated by tracking the pressure change in the test section. Laser transmission through the plasma was also measured to quantify two energy loss mechanisms: incomplete laser absorption and radiation of heat to the walls of the test section. Minimizing these losses would be critical in the realization of a practical and efficient laser-thermal propulsion (LTP) thruster, as most of the laser energy should be deposited as heat in the propellant to maximize thruster specific impulse.

The use of small satellites, enabled by the standardization of the CubeSat specifications and miniaturization in electronics, has seen a rapid increase in the past decades. The low-cost and short development time of these satellites has made them an attractive option for both commercial and academic applications, making space exploration more accessible. However, these small satellites are prone to failures, leading to lost scientific potential. Mitigation of these failures forms the motivation for this thesis. Recent advances in neural networks have shown promise in the field of anomaly detection. The black-box nature of such models, however, makes it challenging to understand the reasoning behind their predictions.

Constraining the data-driven models with known physics can not only help us understand the reasoning behind their predictions, but also ensuring the model is consistent with the real-world behavior of the system. The work presented in this Master's thesis aims to demonstrate the advantages of such first-principles neural networks over purely data-driven models in thermal behavior modeling of small satellites. Baseline performance of data-driven Long Short-Term Memory (LSTM) networks is established using FUNCube-1 telemetry data, quantifying the temperature prediction accuracy of the models under ideal conditions. The limitations of these models, especially with sparse data, are then investigated, to highlight the need for more robust models.

First-principles models, based on a physics-informed curve-fit and simplified thermal network models, are then developed to constrain the data-driven model predictions. The first-principles models are shown to be more robust to sparse data, with the predictions on data not seen during training being more consistent with the real-world thermal behavior of the satellite. Methods to relate the first-principles model parameters to the physical properties of the satellite are also proposed and explored, to help extract the evolution of the thermal behavior of the satellite over time.

Small satellite systems such as CubeSats and PocketQubes have strict requirements in terms of size, weight, and power available onboard. In light of these constraints, small satellite systems typically omit the inclusion of a ranging system due to its power and specialized hardware requirements. However, new research in satellite ranging invented the telemetry ranging class of techniques which do not place any such requirements on the satellite. The thesis explores the possibility of implementing a telemetry ranging technique on the Delfi-PQ satellite, which is already in orbit using only software modifications. The working and performance of the technique in determining the position of the satellite were explored using its engineering model and have positive implications for small satellite navigation and science.

To answer the question of habitability of other planets, it is crucial to find liquid water. As a planet’s surface might be difficult to characterise through observations, the observation of cloud composition and coverage could possibly reveal the presence of large bodies of surface water. Climate code SPEEDY is used to investigate relations between cloud patterns on rocky exoplanets with oceans for various planet parameters, such as obliquity and incident stellar flux, and the observable signals of such exoplanets are computed. SPEEDY was chosen for the modelling of rocky exoplanets, because of its speed, since our aim is to run simulations for various planet parameters, and its flexibility, since it allows the adaptation of planet properties such as the presence and distribution of continents. The planet’s rotational period is found to have the most obvious influence on the cloud pattern: with increasing rotational speed, bands of clouds form, parallel to the equator, with the number of bands increasing with the rotational speed. The total flux and polarisation of starlight that is reflected by the planets with cloud bands as functions of the wavelength and the planetary phase angle are computed. Also the influence of the integration time of the observations on the reflected light signals is studied. Our main recommendation for further research is to broaden the applicability of SPEEDY for exoplanet research by first gaining more insight into the parametrisations and then by adapting them where necessary to allow wider parameter settings.

The number of objects in space is increasing over time, and therefore it is desired to find more efficient propagation models in terms of accuracy and computational speed. This thesis project focuses on the propagation of the state and uncertainties of Potential Hazardous Asteroids, to predict potential Earth impacts. A machine learning technique is proposed to reduce the computational expensiveness of current propagation techniques. The PHA position and the error made by the uncertainties are predicted using a neural network, which uses data from currently known PHAs. Several options are considered regarding the input and output variables and the networks are also tuned. The aim for the best model is to find a reasonable accuracy for the prediction of the position and the uncertainty of newly discovered PHAs.

The use of low-thrust propulsion for interplanetary missions requires the implementation of new methods for the preliminary design of their trajectories. This thesis proposes a method using the Monotonic Basin Hopping global optimization algorithm to find feasible trajectories with optimum use of the mass of fuel for the case in which the trajectory is modeled using the Sims-Flanagan transcription method. Due to the large computational time required to find the global optimum, Artificial Neural Networks have been used to predict the objective value and feasibility terms of the local minimum. Therefore, the procedure to set up a working regression Artificial Neural Network is studied as well as its transferability to predict values outside the trained limits and for different missions. In addition to this, the use of pre-training is analyzed to improve the performance of the network without increasing the size of the training database.

Within a Protoplanetary disk (PPD), planets form from micron sized particles, but what are the processes taken for planet formation? How does the evolution of micron sized particles via settlement and coagulation lead to the gigantic planets as the ones in our Solar System? This thesis explores the planet formation process of pebble accretion which is a planet accretion model involving the accretion of smaller bodies onto larger planetesimals. The evolution of micron sized particles into millimetre – centimetre sized pebbles are discussed. These particles will experience growth via settlement and coagulation, radial drift before acting as reservoir for planet cores to accrete and grow from. From the results, it is found that planet formation via pebble accretion is more efficient in the outer regions of the Solar System, where pebble formation was favoured and resulted in smaller inner planets and larger ice giants.

Interplanetary missions have relied on Radio Science (RS) for recovering gravity fields via detecting their signature on the spacecraft’s trajectory. Yet the weak gravitational fields of small bodies, coupled with the prominent influence of confounding accelerations, hinder the efficacy of this method. Meanwhile, quantum sensors based on Cold Atom Interferometry (CAI) have demonstrated absolute measurements with an inherent stability and repeatability, reaching the utmost accuracy in microgravity. This work addresses the potential of CAI-based Gradiometry (CG) as a means to strengthen the RS gravity experiment for small-body missions. Phobos represents an ideal science case as astronomic observations and recent flybys have conferred enough information to define a robust orbiting strategy, whilst promoting studies linking its geodesic observables to its origin. A covariance analysis was adopted to evaluate the contribution of RS and CG in the gravity field solution, for a mission duration of one week.

The favourable observational geometry and the small characteristic period of the gravity signal add to the competitiveness of Doppler observables. Provided that empirical accelerations can be modelled below the nm/s2 level, RS is able to infer the 6x6 spherical harmonic spectrum to an accuracy of 0.1-1% w.r.t. the homogeneous interior values. If this correlates to a density anomaly beneath the Stickney crater, RS would suce to constrain Phobos’ origin. Yet, in event of a rubble pile or icy moon interior (or a combination thereof) CG remains imperative, enabling an accuracy below 0.1% for most of the 10x10 spectrum. Nevertheless, technological advancements will be needed to alleviate the current logistical challenges associated with CG operation. This work also reflects on the sensitivity of the candidate orbits with regards to dynamical model uncertainties, which are common in small-body environments. This brings confidence in the applicability of the identified geodetic estimation strategy for missions targeting other moons, particularly those of the Giant planets, which are targets for robotic exploration in the coming decades.

Completely regenerative life support systems are essential to the long-term exploration of far-off locations in space. The shift from physico-chemical to bio-regenerative life support systems has the potential to be a major step towards that goal. The cultivation of plants as part of such a system not only provides life support functions and fulfills the dietary needs of the crew, but it also favorably affects human psychology. To maximize these benefits, a potential greenhouse module needs to provide a completely controlled environment for the plants. In this thesis, the Nutrient Delivery System, which is responsible for the root environment for a greenhouse module on the Moon, is designed.

The result is an aeroponic cultivation system supplying two different nutrient solutions of independent compositions to a total growth area of 30.8 m². The distribution can be adapted depending on the respective share of plant species. The important parameters to enable a favorable root environment for plants including the necessary technological capabilities are discussed. For the aeroponic system, diaphragm pumps are chosen that operate at a pressure between 7.6 and 10 bar. They are supported by accumulator tanks reducing pressure spikes and the required number of pump cycles, thus increasing pump lifetime. To provide the optimal root conditions with a minimum of required crew time, the electrical conductivity and the pH are measured and adjusted automatically. Two 550 l tanks are used to store premixed nutrient solutions and are refilled automatically from storage containers. Microbes in the nutrient solution are eliminated by an ozone concentration of 1-3\,mg l. The System is designed to operate autonomously for one month at a time. A preliminary selection of components results in acquisition costs of roughly 32000€, a mass of around 612 kg and a power consumption of 650 W.

The design decisions and key parameters established in this thesis provide a foundation for the execution of the project and its potential far-reaching benefits. As such, the nutrient delivery system design presented here may play a small part in helping to establish self-sufficient settlements in outer space.

Planetary observational accuracy increases and the dynamical modeling of tidal behaviour has to follow. In this thesis, a newly developed method (Correia et al. 2014; Boue et al. 2016) to deal with tidal interactions in a 2D two body problem is validated and for the first time applied to Solar system dynamics on a short time-scale. This method uses a Maxwell rheology for the tidally perturbed body, to calculate the instantaneous deformation of the body with a differential equation at the same time as its position, spin vector and orientation. The coupling between the translational, rotational, and tidal dynamics is incorporated in a consistent way, taking into account the frequency dependency of classical tidal parameters. The coupled model is more general and is in contrast to currently used models valid for every eccentricity, spin rate and orientation. The model is applied to the Mars-Phobos and Earth-Moon systems and the tides are determined separately on both the central as the satellite body in various propagations. Several parameters of tidal effects of these systems are obtained and compared with currently available literature approximations and currently used tidal models. The instantaneous deformation of the tidal body and the evolution of the system's orbit for the tides on the primary compare to the literature approximations and currently used direct tidal force model (Lainey et al. 2007). However, the coupled model displays behaviour of the tidal time lag and angle, which are accompanied with the deformation, that cannot be captured by the classical method. Small differences between final states of the coupled model and the direct tidal force model are obtained that could potentially be important in future space missions and ephemeris determination. The tides on the locked secondary show a larger difference between the coupled model and the current tidal direct force models (Lainey et al. 2007; Lari et al. 2018) in the case of an existing libration. Phobos has such a libration and huge differences in evolution of the states and orbit are found. The coupled model's evolution values can be partly justified by the theoretical work of Efroimsky et al. (2018) that states the additional dissipation in these bodies with large librations. Altogether, currently used methods or literature approximations can still be used for inaccurate propagations. However, for more accurate propagations, and for bodies with large physical librations, it rewards to switch to a coupled method. Especially when regarding the tides on the satellite body a coupled model is beneficial.

The advent of miniaturized satellites has sparked an interest in effective methods of exploiting their capabilities. Potential has been found in propulsion­enabled units, and TU Delft is at the forefront of researching and developing suitable propulsion modules for thrust generation or attitude control of small satellites classified as Cubesats and Pocketqubes for the purpose of technology demonstration, presenting an open platform for students to provide their ideas. Acknowledging the challenges in power budgeting and distribution, the current thesis presents the conception, design and numerical evaluation of a passive, self-­pressurized pro­pellant storage system for use with the in­-house microthrusters. Target components for which the storage must be suitable are the Vaporizing Liquid Microthruster (VLM) and the INKX0511400AA5 VHS Solenoid Lee Valve, an off-­the­shelf component already at the dis­posal of the faculty. Starting from the notion of passive pressurization, an extensive review of literature is used to decide on exploring the idea of compliant mechanisms as a pressuriz­ing method. The scientific output of this work aims to extract productive conclusions on the design and performance level achievable by this concept and open a new design avenue for propellant storage modules. Expanding upon the definition of compliant mechanisms, a considerable amount of design concepts were evaluated under the premise of a two­-stage trade­-off strategy, aiming to balance creativity and practicality. Proclamation of the explored pressurizing mechanism is followed by individual trade­-off procedures for material, shape and configuration of the entire module, leading to a complete preliminary design concept to be evaluated. Traditional and unconventional analytic models are implemented to materialize the design concept, measuring its static and dynamic response in both idle and thrust conditions. They delve into the fields of structural and fluid dynamics and are validated against more advanced and accurate Finite Element (FE) and Computational Fluid Dynamics (CFD) models. Both outputs are compared with the mission, system and subsystem requirements to fully assess the performance levels obtained. Regulated for pressure drops of 500 Pa and 50 Pa from tank to valve, the former is capable of concluding a self-­actuated expulsion within 25 ms in both cases, failing to achieve target values for thrust duration. The conservative design approach has led to a 27.4 gr wet tank mass, with a 2.9 gr propellant capacity. As a first implementation of compliance-based pressurization in propellant storage, the results highlight its viability and the field should be further explored.

Aims: Analysing historical disk-integrated polarization data of Venus with the help of numerical simulations to learn about the time variability in cloud and haze properties, the position of the UV-absorber and the polar cap regions.
Method: With numerical simulations, polarization curves will be calculated for specific input conditions. We compare numerically computed polarization curves to the historical polarization data to derive the microphysical properties of Venus's cloud and haze particles. Results: From our research we obtain values for the imaginary part of the refractive index of the cloud particles of the order 10^(-4). It is most likely that the absorber is mainly located at the equator or in patchy clouds covering 80% of the planet. It is found that in the presence of precise disk-integrated polarization data, it is possible to detect variations in the polar regions. For Venus we found that it is likely that there exist larger particles at higher altitudes at the Venus poles. Unfortunately, it is very hard to say something about the long term variations on the planet. For the Venus case, it can be roughly stated that: the polarization was higher in 1975/1976 than in 1965/1968; the polarization was also higher in 1968/1970 than 1965/1968 but not higher than in 1976; there was a decrease in the polarization of the ultraviolet region in the years 1964/1965. Conclusions: Future observations should be made in a broad range of wavelengths, at as many phase angles as possible and in time frames similar to the orbital period of the (exo)planet. Since Venus can be observed as if it were an exoplanet (broad range of observable phase angles and disk-integrated data), we applied this research to exoplanets as well. We concluded with the help of the Venus data and simple models that it is possible to obtain cloud properties, such as the refractive index and the optical thickness of the cloud, of exoplanets using polarization observations. It was found that those properties are harder to distinguish using flux measurements since the geometric albedo and the distance to the planet are unknown.

Fresnel reflection of starlight in the oceans of exoplanets results in two main phenomena: (1) a glint in the exoplanetary ocean, whose size increases with wind speed, and (2) a maximum degree of polarization at the Brewster angle. The corresponding features in the planetary phase curve, i.e. the flux and degree of polarization of the reflected light by the exoplanet orbiting its parent star, have been studied before. However, these studies did not use (1) horizontally inhomogeneous models, allowing the analysis of the glint appearing and hiding behind patchy clouds and (2) a set of consecutive wavelengths together with (3) a gas layer on top of the clouds. We present the phase curves of the (polarized) flux and degree of polarization of oceanic exoplanets with patchy cloud covers and a substellar cloud for tidally-locked planets. We discuss the spectropolarimetric signatures that could potentially be observed in the near future or that may be considered in the design of future telescopes. We show that (1) a previously suggested method to detect an ocean on an exoplanet, based on the shift of the peak value of the degree of polarization towards the Brewster angle, is sensitive to atmospheric surface pressure, (2) the clouds are not necessarily a limiting factor for detecting an ocean when a gas layer on top of the cloud is considered and a set of wavelengths is used, (3) the phase curves of the different wavelengths intersect in one point whose location could help estimating the cloud fraction and that (4) such an intersection in the polarized flux could be observed in the presence of an ocean for surface pressures up to 10 bar and cloud fractions up to 95%, while it never occurs in the absence of an ocean. We conclude that this color reversal in the polarized flux could potentially be used for detecting oceans on exoplanets.

Over the past many years, technology scaling has resulted in a continuous reduction of lateral and vertical dimensions of transistors. The technology scaling, on the one hand, has led to a commensurate performance gain for very-large-scale integration (VLSI) circuits, but on the other hand, has also made such circuits more vulnerable to ionizing radiations which can cause single event effects(SEEs). These SEEs may cause the underlying user circuitry to deviate from its normal behavior. Devices that are destined for space missions need special protection for such kind of anomalies as space environment is filled with massive amount of high energy particles and ionizing radiations. In this thesis, the design, implementation, and verification of a fault-tolerant r-VEX, a softcore processor, is presented, so that it could be used as an attractive alternative to expensive radiation-hardened processors for space-based applications. r-VEX is a VLIW based, dynamically reconfigurable processor. Keeping in line with its inherent attribute, a dynamically reconfigurable fault-tolerant mode is presented in this work, which provides the running application an option to activate and deactivate the fault-tolerant mode multiple times. In this mode, for the protection of processor pipeline, a non-traditional TMR approach that requires 3 lanegroups running in 2-way mode is implemented. For the reliability of user memories, Hamming codes are implemented as an ECC coding scheme. The functionally of our fault-tolerant design is verified by using both a simulation-based platform (ModelSim) and an on-board FPGA platform (ML605 development kit). To measure the fault-tolerant capabilities of the r-VEX core, saboteurs are used to artificially inject faults at various predefined locations in the core. The obtained results have shown that our design can mitigate all injected single faults in the pipeline and double faults in the caches, without triggering any failure. The dynamically configurable fault-tolerant feature is obtained at the cost of about 30% additional resource utilization and 20% reduction in the maximum operating frequency.

In recent years, private entities have joined the race to send humans to the Red Planet. While Mars is well defined as the next frontier for human space flight, little work has been done towards identifying possible settlement sites on its surface. The current site proposals use a bottom-up approach, that is focusing on one settlement site and then investigating if and why this site fulfils all requirements considered relevant to a human outpost. Here, the Expert System: Settlement (ESS) is presented, a tool that follows the inverse, top-down approach in which initially the entire Martian surface is considered. From there, the set of possible settlement sites is reduced stepwise for various criteria, discharging those sites not fulfilling the specified criteria. Examples of these site requirement are the max. MOLA elevation, the solar power available on the surface, and the water concentration in the subsurface. To cover the different criteria included in this work, the ESS was assembled of the three sub-expert systems Expert System: Engineering Constraints (ESE), Expert System: Climate (ESC), and Expert System: Resources (ESR). The ESS was successfully verified using the engineering constraints defined for the landing site selection of the NASA InSight mission, returning, inter alia, the mission's selected landing site. With view on manned missions, settlement selection constraints were derived from literature to provide input to the ESS. The ESS identified possible settlement sites fulfilling the requirements in Xante Terra/Lunae Planum and West of Elysium Planitia. Other qualifying sites were located in the Northernmost part of Noachis Terra, in Vastitas Borealis between 40°N and 50°N latitude and in Arcadia Planitia, Northwest of Olympus Mons. The ESS is built completely generic, allowing to run the expert system for a variety of possible and diverse mission architectures. Moreover, the code architecture allows to simply add further selection constraints and corresponding planetary data sets required for future selection processes. The ESS is capable of investigating both landing ellipses (as has been done for the NASA InSight mission) and circular exploration zones around a nominal site. Next to settlement site selection, the code developed is therefore also suitable for landing site selection. With suitable data available, the code can be adapted to any celestial body. The current application of the tool regarding site analysis is directly dependent on the available data sets' coverage and maximum resolution; where the latter controls the computation time of the ESS.