[meteorite-list] Planetary Defense: Planning with Phantom Asteroids

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:31:27 2004
Message-ID: <200402241715.JAA16135_at_zagami.jpl.nasa.gov>

http://space.com/scienceastronomy/asteroid_defense_040224.html

Planetary Defense: Planning with Phantom Asteroids
By Leonard David
space.com
24 February 2004

GARDEN GROVE, CALIF. - Authorities in defending the 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 successfully
defend our planet from possible impact threats.

Attention is focused on four fictitious Defined Threat (DEFT) scenarios that
endanger the Earth. The approaching virtual asteroids have been dubbed
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 possible disaster from policy, public
education, and other perspectives.

No known comets or asteroids are presently on a collision course with Earth,
but scientists say an regionally devastating impact -- perhaps in within a
hundred years, more likely not for a thousand or more -- is eventually
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.

The Planetary Defense Conference: Protecting Earth from Asteroids held here
Feb. 23-26 is sponsored by the Aerospace Corporation and the American
Institute of Aeronautics and Astronautics (AIAA).

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 Aerospace Corporation and general chair of the conference.

Ailor told SPACE.com the meeting will recur 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 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 was 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 properly 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 NEO problem.

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, Colorado.

"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.
Received on Tue 24 Feb 2004 12:15:50 PM PST