An inflatable shell for satellites that would allow people to enter and make repairs has been patented. The patent description also points out that radar stealth technology could be built into the shell, suggesting possible military applications.
The patent was awarded to Bigelow Aerospace in November 2005. The company is based in Las Vegas, Nevada, US, and is best known for its plans to build orbiting hotels for space tourists. It launched a one-third scale prototype called Genesis I in July, which is still in orbit (see Inflatable spacecraft releases new images).
The inflatable satellite shell design looks similar to the Genesis I spacecraft, which is basically a watermelon-shaped balloon. But instead of housing people, it would contain satellite components, such as communications antennae. There is an airlock at one end and enough space inside for a person to go in and repair or replace components.
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The patent also mentions ideas for endowing the inflatable shell with 鈥渞adar stealth capabilities鈥�. These include using radar-absorbing materials and designing the shell with a shape that deflects radio waves away from potential detectors, which is how stealth planes work.
Hiding place
The shell would also block the view of any overly curious satellites nearby, by shielding most of the satellite鈥檚 working parts. 鈥淭here would not be any visible way to determine the type of equipment housed in the craft,鈥� the patent notes. The colour of the shell could also be chosen to make the whole structure difficult to spot, the patent says.
These characteristics seem to have been chosen to attract interest and development funds from the US military, says Dan King, a former US air force engineer who now heads King Space Research in Albuquerque, New Mexico, US.
鈥淭his hits on two of the buzz areas that I know DARPA and the Department of Defense have been looking at,鈥� he says. 鈥淭he DoD has talked about modular satellites, where you can go in and do maintenance.鈥� Instead of sending up a new satellite, an old one could be refurbished to improve its capabilities. The US military has also expressed an interest in ways to hide satellites from enemies, he says.
鈥淚t鈥檚 intriguing but it hasn鈥檛 proven out yet,鈥� he says of the satellite shell idea. 鈥淚 could give you tons of projects where people spent millions or billions of dollars but it never went anywhere.鈥�
Eric Haakonstad, who manages Bigelow Aerospace鈥檚 Genesis programme, says the company is not pursuing military applications, despite the patent鈥檚 mention of stealth technology. 鈥淭hat鈥檚 not an avenue we鈥檙e exploring,鈥� he says. 鈥淎ll we鈥檙e doing is sticking satellite communications into a module that has life support. That鈥檚 essentially all the International Space Station is.鈥�
A satellite with life support would allow humans to enter without a spacesuit and do repairs, he says. Whether this would be cheaper than simply sending up a replacement satellite would depend on how expensive the satellite鈥檚 equipment is, he adds.
