DARPA invests in giant space nets to catch trash
Garbage threatens future space elevator plans
By Nancy Gohring | Published: 10:00, 16 August 2010
Forget reality for a minute and try to picture an elegant solution to the problem of space garbage. Imagine that each piece of trash floats in space like a butterfly that can be gently scooped up with a net, preventing collisions. Turns out, that's pretty close to reality. It's the concept behind the Electrodynamic Debris Eliminator, or EDDE, a space vehicle being developed by Star Inc with funding from the US Defense Advanced Research Project Agency.
Jerome Pearson, president of Star Inc, presented the idea for what he calls "a space garbage truck" on Friday at the annual Space Elevator conference. Pearson was an early proponent of the idea of building a space elevator, and a paper he wrote about it in 1975 inspired the description of a space elevator in Arthur C Clarke's science fiction book, The Fountains of Paradise, which popularised the idea.
Space garbage happens to be one of the biggest obstacles to building a space elevator. Pearson's proposed EDDE vehicle will come equipped with around 200 nets, like butterfly nets, that it extends to scoop up garbage in low-earth orbit. Over a period of seven years, 12 EDDE vehicles could capture all 2,465 identified objects over 2 kilograms floating in LEO, Pearson says.
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Once it captures the object, the EDDE can do several things with it. EDDE can fling the garbage such that it lands in the South Pacific, where it has little chance of dangerously landing on anything important. Or, the EDDE can deliver the object closer to Earth where it will orbit out of harm's way and eventually decay.
Better yet, it can be reused in space to build a variety of useful structures, Pearson said. "So you'd be mining aluminium in orbit mainly," he said. Four EDDEs could collect enough metal and other material to build a structure the size of the Smithsonian Air and Space Museum, which could be used to host crews or store equipment, he said.
Pearson acknowledges a number of challenges to the idea behind EDDE. For instance, with 12 or more EDDEs zipping around, "we may need space traffic control," he said. Just like the US Federal Aviation Administration regulates US airspace, that agency has already begun looking at ways it might monitor space, requiring vehicles like EDDEs to file flight plans, he said.
Another possibly significant issue is that while Pearson is proposing the use of EDDEs to clean up garbage, they could potentially be used for more sinister purposes, and that has already raised alarms in China. For instance, an EDDE could be used for military purposes to remove a satellite from orbit. Because of those concerns, Space Inc is working on shifting the project to NASA rather than DARPA, which is part of the US Department of Defence, Pearson said.
He envisions a time when EDDEs could operate under the United Nations, which could tax anyone or any country that launches objects into LEO in order to cover the clean-up of trash there.
Star Inc has already been doing some testing and expects to do a test flight in 2013. If all goes according to plan, a full phase removal of trash could begin by 2017, he said.
About 30 people are attending the Space Elevator conference on Friday, including Yuri Artsutanov, a Russian engineer born in 1929 who published a paper first describing a space elevator in 1960 that went unnoticed outside of Russia.
A space elevator would be a long rope made of nanomaterials, stretching from Earth to a counterweight at geosynchronous altitude, about 22,000 miles (35,406 kilometers) above Earth's surface. Shuttles, like elevator cars, would travel up and down the cable, ferrying people and objects into space.
Two years ago, a speaker at the conference caused a stir when he pointed to the major problem of space garbage, noting that at some point every piece of debris and every satellite would crash into the elevator. "Every one, with no exception," said Ivan Bekey, a former NASA scientist currently with Bekey Designs, at the time.