February 20, 2009

Experts Seek Solution For Space Debris Orbiting Earth

Experts gathered in Vienna, Austria this week to discuss solutions to deal with vast amount of space junk that is clogging up the Earth's orbit.

With a recent satellite collision still fresh on their minds, some suggested that a massive cosmic cleanup is the best way to solve the problem, while others argued that improving information sharing is a better way to address the issue.

The informal talks, which arose from concerns about the February 10 collision of a derelict Russian spacecraft and a U.S. Iridium commercial satellite, took place on the sidelines of a meeting of the U.N. Committee on the Peaceful Uses of Outer Space, which began Feb. 9 and ends Friday.

The collision, which is still under investigation, generated space debris that could orbit the Earth and threaten other satellites for the next 10,000 years.

Nicholas L. Johnson, NASA's chief scientist for orbital debris, told the Associated Press time would be better spent on minimizing the likelihood of future collisions by that roughly 19,000 objects exist in the low and high orbit around the Earth, including about 900 satellites, but a majority of it is just plain space junk.

Johnson estimated that about a thousand objects larger than 4 inches were created by last week's satellite collision, in addition to many smaller ones.   If more debris accumulates, the chances of similar collisions, which are currently very rare, will increase by 2050, he said.

Johnson, who co-leads an International Academy of Astronautics study exploring ways of extracting space debris from Earth's orbit, said he believes the "true solution" is to either retrieve the junk or push it to a higher altitude before it collides with anything else.

"Today's environment is all right but the environment is going to get worse, therefore I need to start thinking about the future and how can I clean up sometime in the future," he told the Associated Press.

Some of the suggestions at the Vienna meeting sounded somewhat farfetched.   For instance, one idea consisted of attaching balloons to pieces of debris to increase their atmospheric drag, ultimately forcing them back to Earth.  Another proposal, Johnson said, suggested attaching a 10-mile electrodynamic tether to debris that would generate a current, which would enable technicians on the ground to remotely force the debris back to Earth.

But other scientists are skeptical about the plausibility of a cleanup.
Richard Crowther, an expert on space debris and so-called Near Earth Objects, said that extracting debris from space was expensive, and risked causing more collisions or explosions that, in turn, would generate even more space junk.

Crowther, the top British delegate to the meeting, suggested it was vital to improve information-sharing regarding the location of orbiting objects in order to minimize future collision since each crash generates more debris, further congesting Earth orbit.

"The information to a large extent is out there, but the owners of the data tend to keep the information to themselves," Crowther told the Associated Press, adding that the United States had been "very good" about making its data publicly available.

Brian Weeden, technical consultant at the nonprofit Secure World Foundation, said the ideal solution would involve the creation of a global network that would gather data on the whereabouts of space debris into a clearinghouse accessible to all.

"The vision we have is a network where a number of different countries "” each of which has a sensor or radar "” contributes data from that sensor or radar to a central location," Weeden told the AP.

The European Space Agency (ESA) has started a new program that seeks to meet that goal by tracking space debris and establishing uniform standards to prevent future collisions.  Launched in January, the $64 million initiative, known as Space Situational Awareness, aims to increase information about the estimated 13,000 satellites and other man-made structures orbiting the Earth.

However, a global system is not likely to be a reality any time soon, since no state has pledged official support.  However, Weeden said that the U.S., France and others have expressed interest.  


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