Image: Asteroid strike
Don Davis  /  NASA
An artist's conception shows a huge asteroid striking Earth. Scientists say even a smaller asteroid — measuring, say, 100 yards across — could create havoc if it hit an urban area.
By Senior Space Writer
updated 2/24/2004 6:10:38 PM ET 2004-02-24T23:10:38

Authorities on defending Earth from a cosmic run-in with an asteroid or comet have gathered here to detail ways to thwart future impacts and deal with the calamity if our planet is struck.

An international group of scientists, engineers, space policy makers, and others are taking on the task of improving our ability to defend the planet from possible impact threats.

Attention is focused on four fictitious Defined Threat, or DEFT, scenarios that endanger the Earth. The approaching virtual asteroids include D’Artagnon, Athos, Aramis and a long-period comet called Porthos. At this time, none of these names is assigned to a real asteroid or comet.

The DEFT scenarios — which include various trajectories and time-to-impact assumptions — are meant to spur designs of rendezvous, intercept and deflection missions and spark discussion of how the world community might prepare for mitigation efforts or a possible disaster from the perspectives of policy and public education.

No known comets or asteroids are presently on a collision course with Earth, but scientists say a regionally devastating impact — perhaps within a hundred years, more likely not for a thousand or more — is inevitable. Yet there are no governmental plans to deal with diverting or destroying an asteroid, managing regional evacuations or dealing with the chaos that might ensue from a collision.

"Planetary Defense Conference: Protecting Earth from Asteroids," held here Monday through Thursday, is sponsored by The Aerospace Corporation and the American Institute of Aeronautics and Astronautics.

Process of being prepared
"We’re looking at the entire issue … from the hazard itself through the political and policy issues, as well as disaster mitigation," said William Ailor of The Aerospace Corporation, general chair of the conference.

Interactive: Below the belt Ailor told Space.com that the meeting will take place every four years. "That way we can assess changes that have, hopefully, increased our abilities to deal with these kinds of threats … and assess current political realities," he said.

"We’ve got the capability to do something about a threat now — at least we may have," Ailor said. "Certainly we could, over a period of time, develop some expertise that would allow us to mitigate a reasonably sized threat.

"But if we don’t start thinking about this, it’s not going to happen. So that’s the purpose here … to start the process of being prepared."

A session chair at the conference is Rusty Schweickart, former NASA astronaut and now director of the B612 Foundation, a nonprofit group dedicated to developing and demonstrating the capability to sidetrack asteroids that might smack into Earth.

"The fact is that a devastating asteroid impact with Earth is a low-probability event, it is not zero. It has happened before. If we do not prevent such an occurrence when we have the capability to do so, it would be the greatest crime in human history," Schweickart said.

Reality strikes
Planetary defense advocates don’t need to dig too far into history to make their case for being better-prepared.

For example, on the night of Jan. 13-14 of this year, the asteroid detection community faced an unprecedented real-world situation. Preliminary predictions of the trajectory of newly spotted asteroid AL00667 showed it on a course to possibly hit Earth within a few days.

The object was roughly 100 feet (30 meters) in diameter — big enough that ground damage, even public injury, could not be ruled out. The distinct possibility of AL00667 striking Earth remained uncertain for several hours.

Follow-up observations of where the asteroid should have been if it were on a heading to mess up Earth proved negative. The rock’s true orbit was found not to intersect with our planet.

A behind-the-scene drama played out among a tight group of asteroid experts and professional as well as amateur astronomers — all without the doom and gloom of scary newspaper headlines and TV reports that have plagued asteroid observations in past years.

The event, nonetheless, left a small group of experts arguing vehemently about what should and should not have been done with the initial observations of AL00667. In recent days, the scientists have traded barbs and accusations over how to evaluate and release data on space rocks that might be headed our way. Among their concerns is how the public might react to an impending threat, and how they might not react if scientists cry wolf too many times.

While a small asteroid like AL00667 could hit Earth with only a few days' notice, larger planet-rattlers would likely be spotted years or decades before impact.

Human aspects of the problem
Social scientists have been studying disasters for 50 years, but only recently has any of that knowledge been brought to bear on the problem posed by near-Earth objects.

While delving into the technical and operational details of deflecting or destroying threatening asteroids is critical, the "human aspects" of the problem are crucial too, said Dan Durda, a space scientist from the Southwest Research Institute in Boulder, Colo.

"How would responsible officials and the public actually react to the prospect of a major impact three or four decades in the future?" Durda wonders. "What would we do if we had very short notice of an impending, very small scale event? Is there enough redundancy in the critical programs that monitor the impact hazard and connect the network of observers and orbit calculators? These issues are as important, and perhaps even more difficult to deal with, as the technical ones involving the physical act of deflecting or destroying a threatening asteroid."

Durda said the recently announced White House space vision is redefining and refocusing NASA's space exploration and human spaceflight priorities.

"I believe that the near-Earth asteroids can and should play an important role in this process," Durda explained. "The same technologies and techniques that we will need to develop to routinely explore the moon and Mars and to extract resources from near-Earth asteroids are the same ones that we could one day need to employ to ward off an impending impact."

Durda added: "I'm sure we'll be doing the former long before we'll ever need to do the latter, but it'll sure be nice to have had the practice first!"

New opportunities
"I think this is the first [meeting] that promises to get the scientists and the engineers together in the first really meaningful way. And the social scientists and policy makers are here, too," said Clark Chapman, an asteroid expert from Southwest Research Institute. "I am personally hopeful that this will be a venue for really serious consideration of the B612 concept — and other equivalent or competing ideas — because the aerospace companies will be mixing with the rest of us."

Furthermore, Chapman said, there are new opportunities in the new environment at NASA after President Bush set a course in January to put humans back on the Moon. Those opportunities, he added, could go in the wrong direction as far as asteroid researchers are concerned.

"But at the moment there is reason for some optimism that this may be a better environment, from this parochial perspective," he said.

Chapman said that he hoped attention to the recent AL00667 incident "may finally nudge some people into seriously developing protocols for dealing with these mini-crises, which many scientists believe are bound to recur."

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