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Radiation and thermal cycling must not degrade thermal-control surfaces or joints in materials possessing different coefficient of expansion. The presence of atomic oxygen in low Earth orbits, a relative newcomer in environmental effects, has been seen to lead to the erosion/corrosion/oxidation of many material surfaces, and more coatings with good atomic oxygen durability need to be developed. These aspects will be detailed in Chap. 8. Requirements for Spacecraft Materials (b) Sublimation and evaporation The minimum altitude for an Earth-orbiting satellite is 200 km (125 miles), and, once this altitude has been reached, appreciable changes can be produced in common engineering materials, whether they be metals, plastics, or ceramics.

By simply modifying the paint finish of the spacecraft surface, or by the attachment of reflective mirrors, it was found possible to adjust and reduce the local temperature environment of each subsystem or equipment and reduce the chance of thermally induced failures. Workmanship problems abounded, with non-conformances relating to open circuits in cable harnesses due to wires separating from crimp barrels and cold soldered joints on circuit boards (such events became less frequent once operator and inspector training schemes were introduced—see Sect.

The enormous amount of energy released during launch can be witnessed from Fig. 2. Weakness in designs may be exposed by this model, such as failures resulting from fatigue of welds, struts, electronic box hold-down points, and the like. The thermal model was subjected to solar simulation and thermal balance testing to confirm and update previously determined mathematical models. During these tests, deficient designs may promote several material failures related to thermal fatigue, overheating, and embrittlement of incompatible joining techniques and metal alloys.