- In Space, No One Can Hear You
Daniel S. Burgess
HUNTSVILLE, Ala. -- Space is a mess. Thousands of satellites race above us, as do thousands of bits of junk. With the International Space Station up and running for at least the next 20 years, the threat of a catastrophic collision with space debris is very real. Thankfully, a laser-based system that promises to clean the cluttered skies is in the works.
Dubbed Project Orion, the system would use a laser to destabilize the orbits of the 150,000 debris objects that are 1 to 10 cm in diameter. "Basically, we're teasing the particle into a lower orbit so the atmosphere burns it up for us," explained project leader Jonathan W. Campbell, an advanced projects scientist at NASA's Marshall Space Flight Center.
Spacecraft can be -- and the space station is -- shielded against objects smaller than 1 cm in diameter. The US Space Command at Peterson Air Force Base, Colo., tracks space debris larger than 10 cm and can warn craft to take evasive action. There is no system to deal with the mediation trash, however.
"To put the threat in perspective," said Claude R. Phipps, Orion's creator, "with a typical relative collision velocity of 12 km/s, a penny delivers the kinetic energy of a Volkswagen hitting a brick wall at 50 mph." Phipps, president of Photonic Associates of Santa Fe, N.M., has worked with Campbell on several projects, including investigations into launching ultralight satellites with lasers.
Using adaptive optics to optimize the shape of the beam for atmospheric transmission, Orion would deliver 15-kJ pulses of near-infrared energy from a 2-Hz Nd:glass or iodine laser to these targets. Surface ablation should produce plasma jets with sufficient thrust to decay an object's orbit and cause it to burn up on re-entry.
Since Orion is a ground-based system based on existing lasers, including the Beamlet prototype developed for the National Ignition Facility in Livermore, Calif., deployment costs should be low. "For about $200 million you could remove all the debris from under 800 km in two years," said Campbell.
Who will buy?
Together, the US and Russia are responsible for more than 90 percent of the debris that Space Command tracks. Of the $60 billion or so in orbiting assets threatened by the hyperkinetic junkyard, however, a large share belongs to private companies. The question remains: Who will pay for the cleanup?
"I believe it is very important that Orion be built as an international cooperative enterprise," Phipps said, adding that the financial burden should fall to the US, European, Japanese and Russian space agencies. "Otherwise, it will be viewed as a wolf in sheep's clothing, a potential antisatellite weapon, and its construction could be destabilizing."
The technology exists to make the system a reality, he said. "What is missing so far is the will to put it all together."
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