[meteorite-list] Space Rock Debate Rolls On

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:08:19 2004
Message-ID: <200209010523.WAA03662_at_zagami.jpl.nasa.gov>

http://www.floridatoday.com/news/space/stories/2002b/090102debate.htm

Space rock debate rolls on

Experts discuss options to protect Earth from hit

By John Kelly
FLORIDA TODAY
August 31, 2002

The dinosaurs didn't know what hit them.

Humans might know that a three-mile wide asteroid is heading right for
Earth. We might even know the date, years or decades before, when the big
rock will bore through our atmosphere and slam into Earth with enough force
to envelope the planet in dust, water, fire or some deadly combination.

Science and technology make it possible to spot near-Earth objects, track
their orbits and even predict where they might go. And advances in
spacecraft, propulsion and weaponry might make it possible for humans to do
something to divert or destroy a dangerous asteroid, comet or meteor.

More important than those advances, however, might be attitudes. Serious
minds in the science, space and defense communities once laughed off
investing time and money in systems designed to protect the planet from
the incredibly remote possibility of a devastating asteroid impact, but
dozens of experts in those fields will gather this week in Washington to
discuss those very questions.

For the next few days, people from prestigious universities, aerospace
companies, think tanks, NASA and the Air Force will hole up at a suburban
Virginia hotel for the NASA-sponsored "Workshop on Scientific Requirements
for Mitigation of Hazardous Comets and Asteroids."

The biggest question to be posed, according to University of Maryland
astronomy professor Michael A'Hearn, is: "What is it we need to know about
these bodies before we can intelligently decide what we need to do to
protect ourselves from them?"

With increasing frequency, astronomers are publicly reporting near-Earth
objects whizzing past the planet or making onerous predictions regarding
humongous asteroids which might -- or might not -- be on a collision course
with Earth.

It's not because there are more objects, but because the technology for
spotting such objects is better and more people are using it to watch the
sky. NASA is tracking near misses and potentially hazardous objects. Similar
operations, run by professional and amateur astronomers, are springing up
around the world. The U.S. Air Force may develop an early warning system. As
capability increases, more people in the science community are pushing
policy-makers to at least consider defense options.

"Our preparations are poor and undeveloped," said Clark Chapman, a
Colorado-based scientist with the Southwest Research Institute's space
studies department. "About all that we're doing is looking for asteroids
with some telescopes, and beyond that there is essentially no funded effort
to plan for this kind of unlikely event, although there are people who are
thinking about it, you know, evenings and weekends."

The odds of a globally devastating impact in the next 100 years are about 1
in 5,000. But while some use that to denounce planning any specific defense
system, Chapman said leaders need to continue research and discuss options
"so if we did need to do something we wouldn't have to start from scratch."

There is no shortage of ideas, including some you might have seen at the
local movie theater. Yes, there are proposals to follow the lead of Bruce
Willis in Armageddon and Robert Duvall in Deep Impact by using a
nuclear-type blast to deflect or destroy a potentially dangerous space rock.
Another suggestion is a complex network of laser-firing satellites. Yet
another calls for somehow nudging the object to change its orbital course a
few centimeters, enough to keep it safely away from the path to Earth.

But according to many people going to this week's conference, most of the
ideas are just ideas. Instead, the most important development this week will
be serious sharing of information between diverse groups of people and
organizations who will play a role in further research and who might someday
be called upon to assist in any effort to avert a real crisis.

"There has been a lot of discussion about mitigation, but this workshop is
probably the most serious and objective approach to the problem to date,"
said Dan Scheeres, a University of Michigan researcher devising ways to get
spacecraft close enough to a moving asteroid to monitor, test or even land
on it. "A lot of the good scientific work that touches on this issue has
been more focused on the hazard, which is questions like how big does it
have to be before you get a global effect."

But don't expect the conference to prompt a movement in the scientific
community to push for a multibillion-dollar defense system, said University
of Illinois professor Bruce Conway.

"What is going to come out is a call for a lot more exploration," Conway
said. "We don't know very much about these objects. We've only been to a
handful of asteroids. We've only landed on one. We don't have a very good
idea of what they are made of or how fragile they are. Some people think
they are a solid rock. Others think they are an accumulation of a lot of
smaller pieces that would fragment if we push them around."

That's why more asteroid-studying missions must be done before anyone can
know if defense systems are needed and what strategy would work best,
scientists said. Others are calling for further improvement of the
monitoring systems, or even some formalized cooperative warning system where
science, space and defense agencies in different countries could better
share information.

Alan Harris, of NASA's Jet Propulsion Laboratory in California, said
research should continue into all relevant areas because much of it has
other scientific value.

For example, better propulsion systems might be needed to travel to and work
in close proximity to asteroids and other near-Earth objects. But the value
of such development would be felt throughout the space industry too. That
research is a higher priority than investing what could be billions of
dollars in a single defense system for something that might not happen in
the next million years.

"The cost and/or risk of building a mitigation system in advance of need
outweighs the benefit of having it," Harris said. "However, if an asteroid
on an impact course were to be found, I'd be on the doorstep of the weapons
labs first thing in the morning to order up a remedy. But not before."
Received on Sun 01 Sep 2002 01:23:31 AM PDT