|MadSci Network: Engineering|
The Transhab is not a spacecraft, it is a concept for a module on the International Space Station with potential applications on the Moon and Mars. This is an important distinction because it means that the Transhab does not have to have the structure to support rockets, fuel, etc. during launch like the Space Shuttle, one of our currently used spacecraft. If it did, the concept behind Transhab would not work.
But a space station module would only have to support itself during launch, a much easier requirement. Once in space, the module will have to keep its shape, be airtight, and protect the crew. Plastics, especially those designed for ballistic impact resistance, are strong enough and can withstand the rigors of daily operation in a near Earth orbit. For an experiment, take an unopened 2 liter bottle of soda and start to hit it with the heel of your hand. Rather than breaking, your hand will bounce off the bottle. The Transhab will be very similar to the bottle. Small objects will bounce off. The crew will be protected from larger objects by the Kevlar and Nomex which will act like a bulletproof vest.
The only potential problem is the long range durabiliy of the plastics in low Earth orbit. While oxygen is found as a molecule in the atmosphere, it is often found as an atom in space. It reacts much more readily as an atom than a molecule. Radiation, particularly ultraviolet light, can also degrade plastics. In general, metals are better than plastics over an extended period. The Long Duration Exposure Facility (LDEF) was one of the first experiments to look at the effects of exposing materials in space. In some cases samples actually reacted so much they disappeared! The plastics in the Transhab module would have to be proven to be able to resist the space environment.
But if the plastics can withstand space, the concept is sound and the Transhab offers a good alternative to the current modules.
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