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Dodging a Space Bullet


February 2004
A killer asteroid, the kind of space rock that did in the dinosaurs, is on a collision course with Earth. A fleet of nuclear-powered robots races to the rescue. Humanity's survival hangs in the balance.

By the second bag of popcorn, swarms of robotic MADMEN --- short for Modular Asteroid Deflection Mission Ejector Nodes --- are descending on the doomsday rock. They attack like hungry dragonflies, gouging out chunks and hurling them into space with such force that the asteroid is slowly nudged into a new trajectory. The shift averts the ultimate catastrophe. The human race survives.

Hollywood has been spinning out variations of the theme for years in films like "Armageddon," "Deep Impact," "Fire From the Sky," "Meteor" and "Asteroid." Now, in a gleaming glass office building near Atlanta's Perimeter Mall, a small technology company is taking some of the fiction out of science fiction and proving that, sometimes, science is even stranger than fiction.

Inconspicuous in a building occupied by corporate tenants like H&R Block, Starwood Hotels and Target Stores, a handful of real-life engineers is pondering the defense of Planet Earth. Under a $75,000 NASA contract --- less than a movie studio would pay for a good sci-fi script --- SpaceWorks Engineering Inc. is studying one way the world might someday avert astrophysical Armageddon.

No one at the firm, founded by Georgia Tech aerospace engineering professor John Olds and staffed entirely by Georgia Tech graduates, has illusions that hordes of their MADMEN robots are going to be racing to humanity's rescue anytime soon.

Their study is purely a conceptual exercise. Like an architect's preliminary renderings of a new building, it will provide a few pretty pictures, a paper report and food for thought. If feasible, a defense of the planet would require decades to develop and cost tens of billions of dollars.

But given the near certainty that an asteroid will strike the Earth at some time in the indefinite future, Olds says, it makes sense to think now about ways such a catastrophe might be prevented.

'It's like insurance'

The research is sponsored by the NASA Institute of Advanced Concepts, also based in Atlanta, which funds freethinking, often wildly innovative studies of future space ventures with the understanding that truly visionary ideas may not be practical for decades, if ever.

"When it comes to planetary defense, there are really two basic questions," Olds says. "Is something going to hit us? And what are we going to do about it? It's like insurance. If we wait until we answer the first question, it may be too late to do anything about it."

NASA is making progress on the first question. Over the last decade, ground-based telescopes have identified 2,672 "near-earth objects," whose orbits bring them in the general vicinity of Earth.

One of the latest found, minor planet 2004 CZ1, is a 150-foot-wide space rock that is due Tuesday to pass within 3.8 million miles of Earth --- a virtual hair's breadth in the vastness of space.

By 2008, the NASA-led international Space Guard Survey hopes to have identified the orbits of 90 percent of the largest objects --- a kilometer (0.6 mile) or more in diameter --- that could pose a threat. Any object that large that struck the Earth would cause a planetary catastrophe.

The chances of that happening are one in a half-million years, according to one NASA report. But astronomers say there may be a million smaller rocks careening around the solar system, sufficient to wipe out a large city. The chances of such an impact are estimated at one in 1,000 years.

"It can happen," says Olds. "Just look at Tunguska."

In 1908, what is believed to have been a meteorite or comet exploded three miles above the Tunguska River Valley in Siberia with the force of 1,000 Hiroshima atomic bombs. Because the area was so remote, populated primarily by reindeer herders, casualties are unknown. The blast leveled 800 square miles of forest, felling trees like toothpicks and knocking people down 40 miles away.

The blast wave from the explosion was detected by weather stations as far away as Berlin and the "salmon pink" glow of the fireball was visible in the night sky in London. The Tunguska object is thought to have been less than 200 feet in diameter. Scientists say a similar event on the U.S. East Coast today could kill 1 million people.

Other ideas floated

Over the years, in and out of Hollywood, a number of ideas for deflecting or destroying a doomsday asteroid have been proposed: blasting it into fragments or hitching up a massive engine that would divert it from a collision course with Earth.

The promise and pitfalls of a variety of schemes are on the agenda this month at the American Institute of Aeronautics and Astronautics' Planetary Defense Conference in Orange County, Calif. Scenarios to be considered include the threat of a 360-foot-wide asteroid destined to hit Europe, a comet aimed at the Mississippi Valley and a small asteroid headed for the Pacific Ocean 200 miles off the California coast.

Traditional concepts for intercepting and neutralizing the threat of an incoming asteroid or comet are fraught with problems.

Breaking up an asteroid without changing its trajectory would simply cause Earth to get smacked by smaller fragments. And changing the trajectory would require delivering and assembling an engine powerful enough to move a body the size of a football stadium --- impractical with today's technology.

A.C. Charania, SpaceWorks' "senior futurist," says one possible key to an effective planetary defense may lie in numbers, not in sheer might. The concept invokes Newton's Third Law of Motion --- "for every action, there is an equal and opposite reaction."

An astronaut standing on a doomsday asteroid could, in theory, deflect its path by a miniscule amount simply by throwing a chunk of it into space. Unless he threw a lot of pieces very fast, however, he wouldn't alter the asteroid's course by much.

But Charania says thousands of nuclear-powered robots, working like an army of futuristic tennis ball machines, could launch into space enough of the offending rock, piecemeal, to shift its course by thousands of miles.

Olds says the robotic mass ejectors would be manufactured and stored in space until a threatening asteroid appeared. Then, they would intercept it, land, drill into the surface and use a conveyor-type system to hurl chunks of the asteroid into space.

Building awareness

SpaceWorks engineers say the beauty of the concept is that the armada of robots could be produced anywhere in the world and launched by any country with access to space. The gradual buildup of the robotic defense force would spread the cost of the project --- undoubtedly hundreds of billions of dollars --- over many years.

The SpaceWorks team --- which has done consulting work for a half dozen NASA centers, the Air Force Research Lab, and the Pentagon's Defense Advanced Research Projects Agency --- has no illusions that the world is going to rush to embrace the notion of planetary defense. But the firm hopes to heighten public awareness of what Charania calls the "ultimate weapons of mass destruction in our cosmic neighborhood."

"Our hope is that projects such as ours can concretely lead to better detection systems and mitigation plans to show the extent of the threat and that something can be done against it," he says.

ATTACK OF THE MADMEN
There are so many chunks of debris in space that sooner or later, a collision is all but inevitable. Atlanta-based SpaceWorks Engineering Inc. is using a NASA grant to study one futuristic concept for planetary defense - an armada of robotic spacecraft called MADMEN, for Modular Asteroid Deflection Mission Ejector Nodes.
HOW IT WORKS:
1 - When a threatening asteroid is detected, hundreds to thousands of small spacecraft - stored at a staging area in space - would be dispatched, taking several years to reach their target.
2 - The spacecraft land and anchor on the target asteroid. Each unit would be independently controlled but coordinates its activity with the other MADMEN.
3 - A coring drill removes chunks of the asteroid and ejects pieces the size of golf balls. Over time, the force of the ejection would gradually change the asteroid's course away from Earth.
Illustration shows MADMEN leaving the Earth and approaching targeted asteroids. A second illustration labels the ejector tube, nuclear-powered mass driver system, telecommunications antenna, multidirectional thrusters, landing gear and coring drill, the various parts of a MADMEN. A third illustration compares the size of the 50-foot-tall MADMEN to an average sized minivan.
Sources: SpaceWorks Engineering Inc., NASA
/ TROY OXFORD / Staff

BRUSHES WITH SPACE DEBRIS
Asteroids are rocky objects that range in size from small boulders to bodies that are hundreds of miles in diameter. Most asteroids are concentrated in a belt between the planets Mars and Jupiter.
THE DANGER ZONE
Asteroids that stray from the belt and cross the Earths orbit are called near-earth asteroids. Although the annual probability of the planet being struck by a large asteroid are minute, the result of such a collision could cause a global climatic catastrophe.
A diagram showing Detected near-earth asteroids in 1999.
PROOF OF IMPACT
Craters on Earth are evidence of asteroid impacts. Meteor Crater near Winslow, Ariz., was formed about 50,000 years ago when an asteroid about 150 feet in diameter hit the planet. The crater is nearly a mile wide and 570 feet deep. An impact site off the coast of Mexico is believed to mark the event that led to the extinction of the dinosaurs 65 million years ago.
A diagram of the Earth with dots representing "where most of the impact craters are located."
Sources: NASA, Knight Ridder, staff research
/ TROY OXFORD / Staff

The Original Story from: http://www.space.com/businesstechnology/technology/higher_ground_040222.html


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