06 Fakultät Luft- und Raumfahrttechnik und Geodäsie
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/7
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Item Open Access Smart ground support equipment : the design and demonstration of robotic ground support equipment for small spacecraft integration and verification(2024) Kottmeier, Sebastian; Wittje, Philipp; Klinkner, Sabine; Essmann, Olaf; Suhr, Birgit; Kirchler, Jan-Luca; Ho, Tra-MiIn order to reduce the costs of integration and verification processes and to optimize the assembly, integration and verification (AIV) flow in the prototype development of small- and medium-sized spacecrafts, an industrial six-axis robot was used as a universal mechanical ground support equipment instead of a tailored prototype specific ground support equipment (GSE). In particular, a robotic platform offers the possibility of embedding verification steps such as mass property determination into the integration process while offering a wider range of ergonomic adaption due to the enhanced number of degrees of freedom compared to a classical static Mechanical GSE (MGSE). This reduces development costs for projects and enhances the flexibility and ergonomics of primarily mechanical AIV operations. In this paper, the robotic MGSE system is described, the operational prospects for in-line verification are elaborated and an example is given showing the possibilities and challenges of its operational use as well as its in-line mass determination capabilities. For this purpose, a method has been developed that allows for the precise measurement of the spacecraft mass using the robot’s existing technology without the need for additional hardware. Subsequent work will extend this to determine the center of gravity and the moments of inertia of the payload on the robotic MGSE.Item Open Access Simulating asteroid impacts and meteor events by high-power lasers : from the laboratory to spaceborne missions(2023) Ferus, Martin; Knížek, Antonín; Cassone, Giuseppe; Rimmer, Paul B.; Changela, Hitesh; Chatzitheodoridis, Elias; Uwarova, Inna; Žabka, Ján; Kabáth, Petr; Saija, Franz; Saeidfirozeh, Homa; Lenža, Libor; Krůs, Miroslav; Petera, Lukáš; Nejdl, Lukáš; Kubelík, Petr; Křivková, Anna; Černý, David; Divoký, Martin; Pisařík, Michael; Kohout, Tomáš; Palamakumbure, Lakshika; Drtinová, Barbora; Hlouchová, Klára; Schmidt, Nikola; Martins, Zita; Yáñez, Jorge; Civiš, Svatopoluk; Pořízka, Pavel; Mocek, Tomáš; Petri, Jona; Klinkner, SabineMeteor plasmas and impact events are complex, dynamic natural phenomena. Simulating these processes in the laboratory is, however, a challenge. The technique of laser induced dielectric breakdown was first used for this purpose almost 50 years ago. Since then, laser-based experiments have helped to simulate high energy processes in the Tunguska and Chicxulub impact events, heavy bombardment on the early Earth, prebiotic chemical evolution, space weathering of celestial bodies and meteor plasma. This review summarizes the current level of knowledge and outlines possible paths of future development.Item Open Access Assessment of high enthalpy flow conditions for re-entry aerothermodynamics in the plasma wind tunnel facilities at IRS(2021) Loehle, Stefan; Zander, Fabian; Eberhart, Martin; Hermann, Tobias; Meindl, Arne; Massuti-Ballester, Bartomeu; Leiser, David; Hufgard, Fabian; Pagan, Adam S.; Herdrich, Georg; Fasoulas, StefanosThis article presents the full operational experimental capabilities of the plasma wind tunnel facilities at the Institute of Space Systems at the University of Stuttgart. The simulation of the aerothermodynamic environment experienced by vehicles entering the atmosphere of Earth is attempted using three different facilities. Utilizing the three different facilities, the recent improvements enable a unique range of flow conditions in relation to other known facilities. Recent performance optimisations are highlighted in this article. Based on the experimental conditions demonstrated a corresponding flight scenario is derived using a ground-to-flight extrapolation approach based on local mass-specific enthalpy, total pressure and boundary layer edge velocity gradient. This shows that the three facilities cover the challenging parts of the aerothermodynamics along the entry trajectory from Low Earth Orbit. Furthermore, the more challenging conditions arising during interplanetary return at altitudes above 70 km are as well covered.Item Open Access 3-D visualization of transparent fluid flows from snapshot light field data(2021) Eberhart, Martin; Loehle, Stefan; Offenhäuser, PhilippThis paper presents the use of light field data, recorded in a snapshot from a single plenoptic camera, for 3-D visualization of transparent fluid flows. We demonstrate the transfer of light field deconvolution, a method so far used only in microscopy, to macroscopic scales with a photographic setup. This technique is suitable for optically thin media without any additional particles or tracers and allows volumetric investigation of non-stationary flows with a simple single camera setup. An experimental technique for the determination of the shift-variant point spread functions is presented, which is a key for applications using a photographic optical system. The paper shows results from different test cases with increasing complexity. Reconstruction of the 3-D positions of randomly distributed light points demonstrates the achievable high accuracy of the technique. Gas flames and droplets of a fluorescent liquid show the feasibility of the proposed method for the visualization of transparent, luminous flows. The visualizations exhibit high quality and resolution in low-contrast flows, where standard plenoptic software based on computer vision fails. Axial resolution depends on the data and is about an order of magnitude lower than the lateral resolution for simple point objects. The technique also allows the time-resolved analysis of flow structures and the generation of 3D3C-velocity fields from a sequence of exposures.Item Open Access Upgrades of a small electrostatic dust accelerator at the University of Stuttgart(2023) Li, Yanwei; Bauer, Marcel; Kelz, Sebastian; Strack, Heiko; Simolka, Jonas; Mazur, Christian; Sommer, Maximilian; Mocker, Anna; Srama, RalfIn this paper, we describe the upgrade of a small electrostatic dust accelerator located at the University of Stuttgart. The newly developed dust source, focusing lens, differential detector and linac stage were successfully installed and tested in the beam line. The input voltage range of the dust source was extended from 0-20 kV to 0-30 kV. A newly developed dust detector with two differential charge sensitive amplifiers is employed to monitor particles with speeds from several m/s to several km/s and with surface charges above 0.028 fC. The post-stage linac provides an additional acceleration ability with a total voltage of up to 120 kV. The entire system of this dust accelerator works without protection gas and without a complex high voltage terminal. The volumes to be pumped down are small and can be quickly evacuated. The new system was used to accelerate micron- and submicron-sized metal particles or coated mineral materials. Improvements in the acceleration system allow for a wider variety of dust materials and new applications.Item Open Access Extension of the plasma radiation database PARADE for the analysis of meteor spectra(2021) Loehle, Stefan; Eberhart, Martin; Zander, Fabian; Meindl, Arne; Rudawska, Regina; Koschny, Detlef; Zender, Joe; Dantowitz, Ron; Jenniskens, PeterThe advancement in the acquisition of spectral data from meteors, as well as the capability to analyze meteoritic entries in ground testing facilities, requires the assessment of the performance of software tools for the simulation of spectra for different species. The Plasma Radiation Database, PARADE, is a line‐by‐line emission calculation tool. This article presents the extensions implemented for the simulation of meteor entries with the additional atomic species Na, K, Ti, V, Cr, Mn, Fe, Ca, Ni, Co, Mg, Si, and Li. These atoms are simulated and compared to ground testing spectra and to observed spectra from the CILBO observatory. The diatomic molecules AlO and TiO have now been added to the PARADE database. The molecule implementations have been compared to the results of a simple analytical program designed to approximate the vibrational band emission of diatomic molecules. AlO and TiO have been identified during the airborne observation campaigns of re‐entering man‐made objects WT1190F and CYGNUS OA6. Comparisons are provided showing reasonable agreement between observation and simulation.Item Open Access Modelling cometary meteoroid stream traverses of the Martian Moons eXploration (MMX) spacecraft en route to Phobos(2021) Krüger, Harald; Kobayashi, Masanori; Strub, Peter; Moragas-Klostermeyer, Georg; Sommer, Maximilian; Kimura, Hiroshi; Grün, Eberhard; Srama, RalfThe Martian Moons Exploration (MMX) spacecraft is a JAXA mission to Mars and its moons Phobos and Deimos. MMX will be equipped with the Circum-Martian Dust Monitor (CMDM) which is a newly developed light-weight (650g) large area (1m2) dust impact detector. Cometary meteoroid streams (also referred to as trails) exist along the orbits of comets, forming fine structures of the interplanetary dust cloud. The streams consist predominantly of the largest cometary particles (with sizes of approximately 100μm to 1 cm) which are ejected at low speeds and remain very close to the comet orbit for several revolutions around the Sun. The Interplanetary Meteoroid Environment for eXploration (IMEX) dust streams in space model is a new and recently published universal model for cometary meteoroid streams in the inner Solar System. We use IMEX to study the detection conditions of cometary dust stream particles with CMDM during the MMX mission in the time period 2024 to 2028. The model predicts traverses of 12 cometary meteoroid streams with fluxes of 100μm and bigger particles of at least 10-3m-2day-1 during a total time period of approximately 90 days. The highest flux of 0.15m-2day-1 is predicted for comet 114P/Wiseman-Skiff in October 2026. With its large detection area and high sensitivity CMDM will be able to detect cometary meteoroid streams en route to Phobos. Our simulation results for the Mars orbital phase of MMX also predict the occurrence of meteor showers in the Martian atmosphere which may be observable from the Martian surface with cameras on board landers or rovers. Finally, the IMEX model can be used to study the impact hazards imposed by meteoroid impacts onto large-area spacecraft structures that will be particularly necessary for crewed deep space missions.Item Open Access An automated system analysis and design tool for spacecrafts(2021) Ehresmann, Manfred; Herdrich, Georg; Fasoulas, StefanosIn this paper, a generic full-system estimation software tool is introduced and applied to a data set of actual flight missions to derive a heuristic for system composition for mass and power ratios of considered sub-systems. The capability of evolutionary algorithms to analyse and effectively design spacecraft (sub-)systems is shown. After deriving top-level estimates for each spacecraft sub-system based on heuristic heritage data, a detailed component-based system analysis follows. Various degrees of freedom exist for a hardware-based sub-system design; these are to be resolved via an evolutionary algorithm to determine an optimal system configuration. A propulsion system implementation for a small satellite test case will serve as a reference example of the implemented algorithm application. The propulsion system includes thruster, power processing unit, tank, propellant and general power supply system masses and power consumptions. Relevant performance parameters such as desired thrust, effective exhaust velocity, utilised propellant, and the propulsion type are considered as degrees of freedom. An evolutionary algorithm is applied to the propulsion system scaling model to demonstrate that such evolutionary algorithms are capable of bypassing complex multidimensional design optimisation problems. An evolutionary algorithm is an algorithm that uses a heuristic to change input parameters and a defined selection criterion (e.g., mass fraction of the system) on an optimisation function to refine solutions successively. With sufficient generations and, thereby, iterations of design points, local optima are determined. Using mitigation methods and a sufficient number of seed points, a global optimal system configurations can be found.Item Open Access Autonomous Planetary Liquid Sampler (APLS) for in situ sample acquisition and handling from liquid environments(2024) Nazarious, Miracle Israel; Becker, Leonie; Zorzano, Maria-Paz; Martin-Torres, JavierMany natural and artificial liquid environments, such as rivers, oceans, lakes, water storage tanks, aquariums, and urban water distribution systems, are difficult to access. As a result, technology is needed to enable autonomous liquid sampling to monitor water quality and ecosystems. Existing in situ sample acquisition and handling systems for liquid environments are currently limited to a single use and are semi-autonomous, relying on an operator. Liquid sampling systems should be robust and light and withstand long-term operation in remote locations. The system components involved in liquid sampling should be sterilisable to ensure reusability. Here, we introduce a prototype of a liquid sampler that can be used in various liquid environments and may be valuable for the scientific characterisation of different natural, remote, and planetary settings. The Autonomous Planetary Liquid Sampler (APLS) is equipped with pre-programmed, fully autonomous extraction, cleaning, and sterilisation functionalities. It can operate in temperatures between −10 °C and 60 °C and pressure of up to 0.24 MPa (~24 m depth below mean sea level on Earth). As part of the control experiment, we demonstrate its safe and robust autonomous operation in a laboratory environment using a liquid media with Bacillus subtilis . A typical sampling procedure required 28 s to extract 250 mL of liquid, 5 s to fill the MilliQ water, 25 s for circulation within the system for cleaning and disposal, and 200 s to raise the system temperature from ~30 °C ambient laboratory temperature to 150 °C. The temperature is then maintained for another 3.2 h to sterilise the critical parts, allowing a setup reset for a new experiment. In the future, the liquid sampler will be combined with various existing analytical instruments to characterise the liquid solution and enable the autonomous, systematic monitoring of liquid environments on Earth.Item Open Access A fast thermal 1D model to study aerospace material response behaviors in uncontrolled atmospheric entries(2022) Pirrone, Serena R. M.; Agabiti, Camilla; Pagan, Adam S.; Herdrich, GeorgA preliminary thermal 1D numerical model for studying the demise behavior of stainless steel 316L, silicon carbide (SiC) and carbon fiber reinforced polymer (CFRP) during uncontrolled atmospheric entry is proposed. Test case modeling results are compared to experimental data obtained in the framework of ESA Clean Space initiative: material samples were exposed to different heat flux conditions using the Plasma Wind Tunnel (PWT) facilities at the Institute of Space Systems (IRS) of the University of Stuttgart. This numerical model approximates the heating history of the selected materials by simulating their thermal response and temperature profiles, which have trends similar to the experimental curves that are found. Moreover, when high heat flux conditions are considered, the model simulates the materials’ mass loss due to the ablation process: at the end of the simulation, the difference between the experimental and the modeled results is about 17% for CFRP and 35% for stainless steel. To reduce the model’s uncertainties, the following analysis suggests the need to consider the influence of adequate material thermophysical properties and the physical-chemical processes that affect the samples’ temperature profile and mass loss.