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'Space Junk' illustrates the growing danger in Low Earth Orbit

This article first appeared in the St. Louis Beacon, Jan 13, 2012 - The OMNIMAX movie "Space Junk" explores the growing problem of man-made debris orbiting the earth at super speeds. The film, which will have its world premiere this weekend, Jan. 14, at the St. Louis Science Center, is designed to raise public awareness of the situation and its impact on satellite communication and space travel.

"It's an honor for the Science Center to launch this movie," Jackie Mollet, senior director of theater, retail and exhibitions, said in a statement. "St. Louis has a long history of leadership in the exploration of space. We hope the film inspires young minds to find solutions to the growing problems that man has created in earth's extended environment."

The scientific space community has long been aware that, as the Low Earth Orbit (between 60 and 600 miles up) fills with space garbage such as spent rocket stages, the likelihood of collisions would become ever more likely. In a 1978 paper, Don Kessler, who later became head of NASA's Orbital Debris Office, predicted that by 2000 collisions would produce debris more dangerous than natural meteoroids in spaces. Collisions would cut big objects into small ones. The little objects -- marble size and smaller -- pose the danger, says Kessler. And at 600 miles up, debris takes about 1,000 years to decay.

Each of these little pieces of debris whizzes around in its own orbit at a speed of about 6 miles a second -- more than six times faster than a speeding bullet. The kinetic energy at that speed is about 36 times that of an equivalent mass of TNT.

The Low Earth Orbit, where the space station and the Iridium satellite band operate, is the crowded part of space. By the 1990s, scientists at NASA realized that man-made environmental hazards in that shell already exceeded meteoroid hazards. They gave the space station a shield to protect it from collisions with these marble-sized missiles.

The prediction of a major collision came true in February 2009 when a defunct Russian Cosmos satellite collided with a working American Iridium satellite at about 500 miles up. That incident created 1.5 tons of shrapnel. These include approximately 100,000 fragments of 1 millimeter or greater, which are large enough to be dangerous, and about 2,000 that are at least baseball size. Each is whizzing around at six miles a second, or 21,600 miles a hour. The debris clouds now engulf the Earth.

Similar damage came from a Chinese anti-satellite test in 2007. That event was unexpected, because China had signed on to an agreement with Inter-Agency Space Debris Coordination Committee, an international consortium of the world's space agencies. With the exception of that incident, however, countries have adhered to the provisions of the agreement such as dumping all fuel to prevent explosions. Even with strict adherence, however, the number of new particles has continued to grow.

If no new satellites or rocket pieces were added to the Low Earth Orbit, it's too late. The tipping point has passed. The pieces already present will continue to generate fragments by collision.

In other words, space must be cleaned up. The film discusses some of the many ideas for performing that Herculean test.

None of the ideas for a space cleanup has been tested because of funding constraints. One possibility is using lasers, but that possibility brings with it the fear of weaponizing space. Another idea would use tethers with nets to scoop up the debris. Launching and retrieving such tethers would be an expensive proposition. And the removal of any large piece of debris must have the permission of the country that put it there or it would be an act of war.

"It's like any other environmental issue," says Kessler. "It always looks like we have plenty of time -- until we don't. The problem grows during the period of inaction until it becomes non-reversible."

Kessler retired from NASA 16 years ago, but has come out of retirement to work on raising public awareness of the implications of space debris.

Kessler and the film's producers, Melissa Butts and Kimberly Rowe, are hoping that their story, told in spectacular computer visualizations, will direct attention to the situation and inspire some young viewers to work on improving it. The film emphasizes that the same natural forces that formed the solar system are behind what is going on in near outer space.

The movie's trailer can be seen on the St. Louis Science Center's website.

Kessler, Butts, and Rowe will be on hand for the members-only preview on Friday, Jan. 13. For regular showtimes, call 314-289-4424 or go to www.slsc.org.

Jo Seltzer is a freelance writer with more than 30 years on the research faculty at the Washington University School of Medicine and seven years teaching technical writing at WU's engineering school