Structure
Space capsules have typically been smaller than 5 meters in diameter, although there is no engineering limit to larger sizes. As the capsule is both volumetrically efficient and structurally strong, it is typically possible to construct small capsules of performance comparable in all but lift-to-drag ratio to a lifting body or delta wing form for less cost. This has been especially pronounced in the case of the Soyuz manned spacecraft. Most space capsules have used an ablative heat shield for reentry and been non-reusable. The Crew Exploration Vehicle appear likely, as of December 2005, to be a ten-times reusable capsule with a replaceable ablative shield. There is no limit, save for lack of engineering experience, on using high-temperature ceramic tiles or ultra-high temperature ceramic sheets on space capsules.
Materials for the space capsule are designed in different ways, like the Apollo’s honey-combed structure of aluminum. Aluminum is very light, and the structure gives the space capsule extra strength. The early space craft had a coating of glass embedded with synthetic resin and put in very high temperatures. Carbon fiber, reinforced plastics and ceramic are new materials that are constantly being made better for use in space exploration.
Read more about this topic: Space Capsule
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