Designing for the Space Environment Via Trade Space Exploration

Open Access
- Author:
- Binz, Christopher
- Graduate Program:
- Aerospace Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- None
- Committee Members:
- David Spencer, Thesis Advisor/Co-Advisor
David Spencer, Thesis Advisor/Co-Advisor - Keywords:
- trade space exploration
space environment
design optimization
atsv
spacecraft design
visual steering - Abstract:
- The focus of spacecraft design has long been on cost efficiency. Many options exist that will fulfill the mission requirements, but the best design is the one which maximizes the return while minimizing the cost. The industry has a number of ways to optimize the design process, but this thesis suggests a new method. The traditional design process includes consideration of space environment effects, but normally these are secondary concerns. This work brings these effects – specifically contamination, radiation, and atomic oxygen attack – to the forefront of the process. An Earth-sensing satellite in low Earth orbit is used as a design example. A basic model is developed in Microsoft Excel, and includes thermal, power, optics payload, and thruster/propellant design issues. In the thermal model, a simple lumped approximation is used, and the effects of thruster plume contamination on the thermal control surfaces are accounted for. The solar panel lifetime is estimated using a model for degradation due to the radiation environment as well as thruster contamination. The optics payload performance is a function of contamination and spacecraft glow. Atomic oxygen erosion of the selected thermal control material is also used as a lifetime estimate. The model allows the designer to input somewhat high-level design variables, such as the dimensions of the spacecraft, and the selection of thermal control material and thrusters; and calculates estimates for relative lifetime, cost, and performance. It is then linked with Penn State’s Applied Research Lab’s Advanced Trade Space Visualization (ATSV) software, which allows designers to use the “design by shopping” paradigm by providing visual steering tools. This setup is used to search for optimal designs in several different cases. The model generally converges in less than 10,000 designs, with many cases converging in fewer than 5,000. The visualization tools easily show trends such as the primary limiting lifetime factor (solar arrays), the effects of a limited propellant budget, and the groups of materials which are best suited for this problem. In addition to showing the single optimal design, the Pareto sets are shown as well. The industry trend towards smaller spacecraft is reflected here, with most preferred designs on the order of 30% of the maximum allowable volume. Feasible designs are found for most thermal materials, and all propellant options. This combination of designing specifically for space environment effects and using visual steering to aid in the optimization process creates a new way for designers to approach the problem.