Tuesday, August 31, 2010

'Butterfly Net' to Collect Space Junk

    'Butterfly Net' to Collect Space Junk
  • DARPA is sponsoring a project to build a butterfly-net-like machine to capture space junk—the massive amount of material left over from rogue satellites, old spaceships and other defunct manmade objects.
  • DARPA is sponsoring a project to build a butterfly-net-like machine to capture space junk—the massive amount of material left over from rogue satellites, old spaceships and other defunct manmade objects.

    A team of scientists is rethinking the concept of the butterfly net on a much larger scale. They've devised a netlike machine to catch all of the dangerous trash that's swirling around our planet.

    Space junk includes all of the now-defunct manmade materials that orbit our planet. It can include anything from trashed rocket stages and obsolete satellites to fragments left over from explosions.

    A huge amount of manmade debris currently orbits Earth (source: NASA).

    While space junk might sound harmless, keep in mind it's whirling around at thousands of miles an hour. At that speed, even a tiny speck of dust can cause significant damage to spacecraft—an especially troublesome risk for solar panels and protective shielding, which guards a craft from space's extreme temperatures and radiation.

    A recent NASA study addressed just how hazardous space junk can be. "The greatest risk to space missions comes from non-trackable debris," says Nicholas Johnson, NASA chief scientist for orbital debris. Such declarations have led to increased research on solutions for preventing collisions with space junk, and collecting the rubbish.

    Star, a Mount Pleasant, S.C.-based technology company, is working on a machine called the ElectroDynamic Debris Eliminator (EDDE). The project, which is funded by U.S. Defense Advanced Research Project Agency (DARPA), aims to collect space junk in an efficient and complete manner.

    The EDDE vehicle is equipped with 200 nets that can collect garbage currently in low-Earth orbit. Jerome Pearson, president of Star, claims that, over seven years, just 12 of these vehicles could collect all 2,465 identified objects weighing over 2 kilograms that are floating around the planet.

    Even tiny bits of debris can cause substantial damage to spacecraft. Here, a large pit has been made in a space shuttle's window (source: NASA).

    Once a piece of debris has been collected, the EDDE has several disposal options. For example, the vehicle could send an object toward Earth, where it will land harmlessly in unpopulated regions of the South Pacific. It can also bring an object into a closer orbit, which will eventually cause most pieces of debris to burn up in the atmosphere.

    The most exciting disposal option, however, is the possibility of space recycling. The EDDE could salvage materials from debris and manufacture new, working parts. "So you'd be mining aluminum in orbit," Pearson states. According to Star, just four of the machines could collect enough material to build a structure as big as the Washington, D.C. Smithsonian Air and Space Museum—that's nearly 200,000 square feet.

    Despite these exciting possibilities, the project faces several challenges. First, having many EDDEs zooming around Earth would require more regulation for safety purposes. "We may need space traffic control," Pearson posits. The U.S. Federal Aviation Administration has already begun research on how it might standardize space flights. For example, vehicles like the EDDE might someday be required to file flight plans, just like airplanes do.

    Another noteworthy concern is that the vehicle could be used for military functions, such as disabling other countries' satellites. This possibility already has Chinese officials worried. To combat these concerns, Star hopes to move its project from the Department of Defense to NASA. Pearson even hopes that the machine might eventually be governed by the United Nations, which could regulate international space clean-up efforts.

    Star has already begun testing its vehicle, which should commence test flights in 2013. The company plans to start removing space junk by 2017.

    A simulation of how 12 EDDEs could effectively clean the space around Earth can be found here.

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