06 Fakultät Luft- und Raumfahrttechnik und Geodäsie
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/7
Browse
3 results
Search Results
Item Open Access Enhanced algorithms to ensure the success of rendezvous maneuvers using aerodynamic forces(2021) Bühler, Simon; Traub, Constantin; Fasoulas, Stefanos; Herdrich, Georg H.A common practice in the field of differential lift and drag controlled satellite formation flight is to analytically design maneuver trajectories using linearized relative motion models and the constant density assumption. However, the state-of-the-art algorithms inevitably fail if the initial condition of the final control phase exceeds an orbit and spacecraft-dependent range, the so-called feasibility range. This article presents enhanced maneuver algorithms for the third (and final) control phase which ensure the overall maneuver success independent of the initial conditions. Thereby, all maneuvers which have previously been categorized as infeasible due to algorithm limitations are rendered feasible. An individual algorithm is presented for both possible control options of the final phase, namely differential lift or drag. In addition, a methodology to precisely determine the feasibility range without the need of computational expensive Monte Carlo simulations is presented. This allows fast and precise assessments of possible influences of boundary conditions, such as the orbital inclination or the maneuver altitude, on the feasibility range.Item Open Access Analysis of collision avoidance manoeuvres using aerodynamic drag for the Flying Laptop satellite(2023) Turco, Fabrizio; Traub, Constantin; Gaißer, Steffen; Burgdorf, Jonas; Klinkner, Sabine; Fasoulas, StefanosCollision avoidance is a topic of growing importance for any satellite orbiting Earth. Especially those satellites without thrusting capabilities face the problem of not being able to perform impulsive collision avoidance manoeuvres. For satellites in low Earth orbits, though, perturbing accelerations due to aerodynamic drag may be used to influence their trajectories, thus offering a possibility to avoid collisions without consuming propellant. Here, this manoeuvring option is investigated for the satellite Flying Laptop of the University of Stuttgart, which orbits the Earth at approximately 600km. In a first step, the satellite is aerodynamically analysed making use of the tool ADBSat. By employing an analytic equation from the literature, in-track separation distances can then be derived following a variation of the ballistic coefficient through a change in attitude. A further examination of the achievable separation distances proves the feasibility of aerodynamic collision avoidance manoeuvres for the Flying Laptop for moderate and high solar and geomagnetic activity. The predicted separation distances are further compared to flight data, where the principle effect of the manoeuvre on the satellite trajectory becomes visible. The results suggest an applicability of collision avoidance manoeuvres for all satellites in comparable and especially in lower orbits than the Flying Laptop , which are able to vary their ballistic coefficient.Item Open Access Satellite design optimization for differential lift and drag applications(2024) Marianowski, Claudia; Traub, Constantin; Pfeiffer, Marcel; Beyer, Julian; Fasoulas, StefanosUtilizing differential atmospheric forces in the very low earth orbits (VLEO) regime for the control of the relative motion within a satellite formation is a promising option as any thrusting device has significant impact on system design due to the limited weight and size restrictions of small satellites. One possible approach to increase the available accelerations caused by the atmosphere is to reduce the mass of the respective satellites as well as to increase the available surface area. However, satellites of these characteristics suffer from rapid orbital decay and consequently have a reduced service lifetime. Therefore, achieving higher control forces is in contradiction to achieving a minimum orbital decay of the satellites, which currently represents one of the biggest challenges in the VLEO regime. In this article, the geometry of a given reference satellite, a 3UCubeSat, is optimized under the consideration of different surface material properties for differential lift and drag control applications while simultaneously ensuring a sustained VLEO operation. It is worth noting that both the consideration of sustainability as well as the optimization with regard to differential lift are new in literature. It was shown that the advantageous geometries strongly depend on the type of gas-surface interaction and thus, two different final designs, one for each extreme type, are presented. In both cases, improvements in all relevant parameters could be achieved solely via geometry adaptions.