TransHab was a concept pursued by NASA in the 1990s to develop the technology for expandable habitats inflated by air in space. Specifically, TransHab was intended as a replacement for the already existing rigid International Space Station crew Habitation Module. When deflated, inflatable modules provide an 'easier to launch' compact form. When fully inflated, TransHab would expand to in diameter (compare to the diameter of the Columbus ISS Module). History The name of the project is a contraction of Transit Habitat reflecting the original intention to design an interplanetary vehicle to transfer humans to Mars. Considerable controversy arose during the TransHab development effort due to delays and increased costs of the ISS program. In 1999, the National Space Society issued a policy statement recommending that NASA continue R&D of inflatable technologies while ceasing development of a TransHab ISS module. Finally in 2000, despite objections from the White House, House Resolution 1654 was signed into law banning NASA from conducting further research and development of TransHab. An option to lease an inflatable habitat module from private industry was included in the bill. Since that time, the private company Bigelow Aerospace has purchased the rights to the patents developed by NASA and is pursuing a similar scheme for a private space station design. The company has launched the Genesis I, Genesis II, and BEAM pathfinder spacecraft, with plans for additional experimental craft culminating in their BA 330 production model and the Bigelow Commercial Space Station. Technology The TransHab design called for a hybrid structure that combines the packaging and mass efficiencies of an inflatable structure with the advantages of a load-bearing hard structure. Multi-Layer Inflatable Shell TransHab's inflatable shell consisted of multiple layers of blanket insulation, protection from orbital and meteoroid debris, an optimized restraint layer and a redundant bladder with a protective layer. TransHab's foot-thick inflatable shell design had almost two dozen layers. The layers were fashioned to break up particles of space debris and tiny meteorites that might hit the shell with a speed seven times as fast as a bullet. The outer layers protect multiple inner bladders, made of a material that holds in the module's air. The shell also provides insulation from temperatures in space that can range from plus 121 degrees Celsius (plus 250 degrees Fahrenheit) in sunlight to minus 128 degrees Celsius (minus 200 degrees Fahrenheit) in the shade. The key to the debris protection in