Sierra Space has completed a key test of its inflatable space habitat, as the company moves towards launching and operating a private space station with Blue Origin before the end of the decade.
“Maximum burst pressure” testing of the inflatable module was carried out at NASA's Marshall Space Flight Center. As the name suggests, the purpose of the test is to inflate the unit until it explodes. In this case, engineers inflated the module to 77 psi before it exploded, showing that it exceeded NASA's recommended safety level of 60.8 psi by 27%.
While Sierra has conducted a series of blast tests on subscale units of the habitat, called Large Integrated Flexible Environment (LIFE), this is the first on a large-scale module. At full scale, the module measures more than 20 feet tall and about one-third the volume of the International Space Station.
As Sierra systems engineer Leanne Thompson noted in a recent video about the test, NASA needed between 10 and 15 launches to send that same volume of habitable space to the ISS. Each LIFE module is designed to fit inside a standard five-meter payload fairing, although the company said it is working on larger 1,400 cubic meter iterations (larger than the ISS) that could fit into a seven-meter fairing. .
The test focused on the pressure layer or restriction layer of the LIFE habitat, which is made of expandable “soft materials” that function as a rigid structure once inflated. Soft goods as a materials category have aerospace heritage: inflatable airlocks have been installed on the ISS, and demonstration modules developed by Bigelow Aerospace were launched into space in the 2000s.
The textile products that make up the LIFE habitat include Vectran straps, which are made from high-performance polymers, and other materials. In a press release, Sierra said Vectran is “stronger than steel when inflated in orbit.” The company is working with ILC Dover to design and test the belts ahead of this full-scale test.
Although the burst test is certainly suggestive, it would be a mistake to compare the LIFE module to a balloon. In the video above, Sierra briefly shows nine layers that will ultimately make up each module, including the containment layer, such as thermal insulation and an outer shell.
Sierra's plan is to deploy the LIFE modules into low Earth orbit as part of Orbital Reef, a private space station the company is developing with Blue Origin. Notably, Sierra specifically references the project in the press release, which could be, at least in part, a response to reports from CNBC last year that the Orbital Reef project was about to collapse.
Sierra said this year will be one of “aggressive” testing both at the sub-scale and at the full scale of the other layers of the habitat.
