SUMMARYThermal modelling of spacecraft requires approaches which can handle dominant radiative heat transfers and many special thermal control components. Present network-type thermal analysers allow simulation, especially for components with rectangular geometries, but at the expense of considerable awkwardness and much error-prone manual input. The user interfaces for pre-and postprocessing for these analysers are also very deficient. Finite element thermal analysers solve some of the analytical difficulties, but are not widely used because they lack the flexibility to simulate special operations. The Galerkin finite element method (GFEM) distributes the contributions within an element to the element nodal points. The assembly of the contributions from all elements yields a system of energy balance equations for the nodal points of the system. Monte Carlo raytracing, in conjunction with a GFEM energy distribution to element nodal points, yields a procedure of consistent nowisothermal surface radiation exchange. This procedure reduces a source of simulation error caused by non-uniform element illumination and shading. Orbital heating, fluid flow and special analysis features are discussed. The main analysis program is interfaced to the preprocessing and postprocessing modules. Example results are given.

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Automated design space exploration was implemented and demonstrated in the form of the multidisciplinary optimization of the design of a space-based telescope. Off-the-shelf software representing the industry standards for thermal, structural, and optical analysis were employed. The integrated thermal/structural/optical models were collected and tasked with finding an optimum design using yet another off-the-shelf program. Using this integrated tool, the minimum mass thermal/structural design was found that directly satisfied optical performance requirements without relying on derived requirements such as isothermality and mechanical stability. Overdesign was therefore avoided, and engineering productivity was greatly improved. This ambitious project was intended to be a pathfinder for integrated design activities. Therefore, difficulties and lessons learned are presented, along with recommendations for future investigations. * To better enable comparisons with the original design case, buckling was again neglected.

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Productivity bottlenecks for integrated thermal, structural, and optical design activities were identified and systematically eliminated, making possible automated exchange of design information between different engineering specialties.The problems with prior approaches are summarized, then the implementation of the corresponding solutions is documented. Although the goal of this project was the automated evaluation of coupled thermal/optical/structural designs, significant process improvements were achieved for subset activities such as stand-alone thermal, thermal/ structural, and structural/optical design analysis. INTRODUCTION: PROBLEM STATEMENTStructural, thermal, and optical engineers typically work independently of each other using unrelated tools, models, and methods. Without the ability to rapidly exchange design data and predicted performance, and therefore to influence each other's efforts, the prior state-of-the-art for the design of advanced optical systems was inadequate: it has henceforth resisted attempts to achieve the ideals of concurrent engineering. Limited success has been achieved at a very top-level (suitable for conceptual design studies), but only by approximating or neglecting the detailed design tasks that the engineering specialist must perform in later mission phases.