Bigelow's inflatable space stations
Sen—Many people are familiar with the memory of a space shuttle blasting off the launchpad powered by gigantic solid rocket boosters and those fortunate to have been around in the 1960s will have been lucky enough to witness the mighty Saturn V moon rocket launch Neil Armstrong and his crew to the Moon. Memories aside, space travel is changing as commercial enterprise develops transport for both crew and cargo.
Many companies are now developing spacecraft that will serve the needs of government agencies, companies wishing to put satellites into orbit and individuals prepared to pay for their space adventure. NASA is one of the space agencies that is hiring the services of private enterprise to deliver cargo and eventually crew to the space station. Recently NASA announced further funding support for some of the US companines developing crewships - SpaceX, Sierra Nevada Corporation and Boeing.
Boeing is building its Crew Space Transportation (CST)-100 space capsule to take humans into orbit. As reported by Sen, the recent drop tests of Boeing's CST-100 were carried out with help from another commercial space business, Bigelow Aerospace. Bigelow Aerospace plans to use the CST-100 to ferry customers to and from its planned Bigelow Orbiting Space Complex, an inflatable space station.
Artist illustration of Boeing's CST-100 capsule approaching Bigelow's BA 330 complex. Credit: Boeing/Bigelow
Bigelow Aerospace's mission is “to provide affordable options for spaceflight to national space agencies and corporate clients” - and they plan to do it, not with multi-billion pound rockets but with large inflatable space stations!
Formed in 1999, Bigelow Aerospace was the brainchild of Robert T Bigelow who wanted to revolutionise space commerce with the development of affordable, reliable, and robust expandable space habitats. His dream became reality in July 2006 with the launch of Genesis I, the company’s prototype expandable space habitat. Its second prototype, Genesis II, was launched June 2007. Both still orbit Earth.
The idea of using inflatable technology is nothing new and goes back to the 1950s when the U.S. launched Echo 1 and Echo 2, the first passive communications satellites. They were huge balloons measuring 30.5 metres across and made from mylar 0.013mm thick (the same material used by amateur astronomers for solar filters) and were capable of reflecting signals around the world. Sadly, with the lack of suitable material to advance the idea further, the development of inflatable space vehicles ground to a halt.
After nearly 40 years of advances in material science, momentum picked up again and it was Kevlar that was the focus for space engineers. NASA started research into the technology again and in 1990 announced plans for 'TransHab', their Transit Habitat for a mission to Mars which was to be an inflatable craft. Sadly again, further development was thwarted in 2000 due to cost challenges within the space agency not helped by the International Space Station running at $4.8 billion over budget.
Robert Bigelow recognised the benefits though and took up the challenge, setting up Bigelow Aerospace in 1999. The company has become the sole commercialiser of a number of NASA’s inflatable technologies. Genesis 1, the first of their craft to be launched into orbit, measured 4.4 metres by 2.54 metres and boasts 11.5 cubic metres of useable space compared to around 800 cubic metres inside the International Space Station. This doesn't sound too impressive granted, but the cost per cubic metre of volume makes it significantly cheaper to launch/operate than the space station. Its primary purpose was to prove the technology worked, and worked it did, impressively so. Launched just a year later in June 2007 was Genesis 2 which was similar in size and appearance to Genesis 1 but had many more systems on board that were not tested by its predecessor. You can track the orbit of Genesis II on the Bigelow Aerospace web site. Along with its various test systems it hosted a rather fun project called 'Fly Your Stuff'. This innovative project allowed anyone, at a cost of US$300, to send their own small items or pictures into space.
Genesis II in orbit. Credit: Bigelow Aerospace
One of the greatest benefits of using inflatable habitats is the protection offered to its inhabitants from radiation. When spacecraft made from more conventional metal structures are exposed to radiation, from events such as a coronal mass ejection, a secondary radiation effect occurs. This can either be from scattering of the radiation, or the atoms in the structure itself can become excited and re-radiate. This doesn't happen with non-metallic materials used in inflatable craft outer skins thereby significantly reducing the risk to its inhabitants.
At the heart of the inflatable technology is a material called Vectran, twice as strong as Kevlar and present in several layers of the 15cm thick skin of the Genesis craft. The flexible nature of the material results in further added safety for potential station inhabitants, a benefit supported by laboratory tests. It was found that micrometeoroids that would puncture the rigid skin of the International Space Station only penetrated half way through the skin of the Genesis craft. Because of its success so far, NASA are in talks with Bigelow for a module to attach to the ISS, called the Bigelow Expandable Activity Module. If it gets the go ahead, it could mean the first step in a new wave of space modules and craft.
Not only is the company talking to NASA about modules for the ISS but they have their sights on their own space station comprised of inflatable modules including their new BA 330 module which will be larger than the Genesis prototypes. The BA 330 space station, with a volume of 330 cubic metres, will be capable of accommodating up to six humans. It has protection from space debris with its "Micrometeorite and Orbital Debris Shield". Hypervelocity tests conducted by Bigelow Aerospace have shown that this shield provides greater protection than a traditional aluminium can design. The BA 330 design includes four large UV coated windows to give the occupants amazing views as they orbit Earth. The inflatable space station would use solar power and batteries and have its own environmental controls and life support system.
The constant need for cost savings and the increasing pressure on governments for health, education and security sadly means the exploration of space takes a back seat on many occasions. The times are changing though and where it was once the government funded organisations like NASA and Russia's space agency who dominated space exploration, its now the commercial organisations like Bigelow Aerospace coming up on the rails who will lead us into a new and exciting era of space exploration.