“He huffed and he puffed and he blew his house up!” The tale of the three little pigs and the big bad wolf may be very different for the first extra-terrestrial children to be read bedtime stories. Inflatable structures for space habitation are advancing to the front as a genuine technology for the early colonisation of off-world destinations. However, you’re unlikely to consider living inside a balloon on Earth, so what makes these structures so appealing for future intrepid explorers?
Inflatable, or to use the industry term, expandable, habitats seem to perfectly suit the space environment. They offer highly efficient space and weight utilisation, allowing them to be packed into a relatively small space on a rocket, in turn making them cheaper and easier to send to their intended destination. Once in space, or landed on the lunar or martian surface, the modules are expanded using compressed air sent up with the module (or the surrounding atmosphere in the case of a martian habitat). Initially you might think these structures to be flimsy, weak and unable to offer much protection against the harsh space environment. However they will not have to withstand the relatively soupy atmosphere of Earth and its unpredictable and often extreme weather. Not that this appears to be a problem, the current effort to fly a solar-powered aircraft around the world (Solar Impulse 2) has an entirely inflatable mobile hangar capable of withstanding 100km/h winds to protect a delicate aircraft with a wingspan larger than that of a Jumbo Jet.
The Solar Impulse team’s inflatable hangar surviving a thunderstorm in Myanmar.
Even more surprisingly, expandable space habitats offer improved radiation and ballistic protection than can currently be found on the longest in service human space habitat, the International Space Station. The non-metallic “vectran” skin won’t be excited by radiation from space and emit more radioactive particles, unlike its aluminium counterpart - reassuring for future astronauts. This double whammy of greater volume and increased protection is a sure-fire advantage in a cost-conscious industry.
US company Bigelow aerospace has big plans befitting of its name. BEAM the Bigelow Expandable Activity Module was recently viewed by NASA officials prior to its launch to the International Space Station on a SpaceX Falcon 9 rocket later this year where it’ll spend 2 years docked with the station. Once fully expanded and operational it will undergo a series of tests to determine if the technology, with its 0.46m walls, lives up to the bold claims of its designers and can successfully survive the challenging environment. Bigelow already have a promising track record with successful demonstrations of smaller scale versions of their technology with the Gemini 1 and 2 missions on 2006-7 and will be looking to secure future contracts to provide expandable modules to private investors.
It’s not just expandables that are paving the way for extra-terrestrial living environments however - 3D printing also has a place in space. Igloo like structures built out of the moon dust or “regolith” fired from a nozzle to form a structure with a similar design to that of a hollow bone, have been considered and even put to the test with promising results by an industrial team lead by the European Space Agency. This technology benefits from ISRU - In Situ Resource Utilisation - making innovative use of the surrounding environment instead of sending all the required raw materials from Earth. ISRU is a major buzz-acronym at NASA and other spacefaring organisations currently - and so it should be, if humanity is to spread beyond the confines of Earth then it is vital to learn how to exploit different natural environments advantageously. With this in mind, Moon igloos may be the answer to permanent lunar settlement rather than the shiny, glass and metal art-deco bases conjured by science-fiction.
It’s still going to be a long time before any real established space, lunar or martian based colonies succeed, however the growing interest in space based opportunities from established business leaders and entrepreneurs will help to push an already rapidly expanding industry forward and allow the proposed technologies develop and mature. It’s not a coincidence that many people often dream of gargantuan orbiting space hotels or sprawling martian bases and it does not seem too far-fetched that sometime soon, someone is going to tap into and successfully commercialise that desire. From what we’ve seen as the demonstrable benefits of expandable technology it’s inevitable that when they do, a blow-up hotel could well be the first thing on their mind.