The supporting structure for systems capable of leaving the Earth and its atmosphere, performing a useful mission in space, sometimes returning to the Earth and sometimes landing on other bodies. Among the principal technologies that enter into the design of spacecraft structures are aerodynamics, aerothermodynamics, heat transfer, structural mechanics, structural dynamics, materials technology, and systems analysis. In applying these technologies to the structural design of a spacecraft, trade studies are made to arrive at a design which fulfills system requirements at a minimum weight with acceptable reliability and which is capable of being realized in a reasonable period of time.