TransHab Up Close

In May 2015, NASA’s BEAM (Bigelow Expandable Activity Module) mission will feature the robotic berthing of one of Bigelow Aerospace’s BEAM modules at one of the interfaces of the International Space Station’s (ISS) Tranquility node. As well as providing much-needed logistics and stowage support for the orbiting outpost, BEAM is expected to provide useful data on the performance of non-rigid space station modules. As discussed in the previous chapter, expandable space station modules are nothing new. But the TransHab discussed in Chapter 2 is not quite the same as the BEAM. While TransHab proved many of the aspects of inflatable module technology, there was still much work to be done. For example, although the NASA team had begun working on how to incorporate windows, putting holes in the module walls complicated the engineering of the skin so much that they left windows out of the proposed ISS module design entirely, although NASA filed a patent describing how windows could be fitted into a module. While details of how Bigelow has evolved the TransHab technology have not been published, one of the improvements was to include windows. To that end, Bigelow engineers conducted pressurization tests of different module designs, often deliberately pushing designs beyond their limits to establish safety margins. These tests often resulted in the module exploding. Fortunately, the team followed NASA’s experience by conducting the pressurization tests under water, which muted the explosive force when the modules ripped apart. In one test, engineers decided to conduct a fill-to-fail test in open air and discovered why NASA hadn’t when the test module exploded with such force that it shook the foundation of the building. In short, TransHab was a starting point for Bigelow’s BEAMs, which is why it’s worthwhile taking a look at the TransHab technology a little more closely.