- WASHINGTON (Reuters) - Baby boomers, breathe easy. Your retirement will
not be ruined by an asteroid collision with the Earth, and your grandchildren
will be safe. But researchers say even if 1997 XF11 had been headed toward
Earth, it would have been easy to deflect. The International Astronomical
Union (IAU), which keeps track of such objects, said late Wednesday that
an asteroid would pass very close to the Earth in the year 2028 and might
conceivably hit it. But NASA said its calculations showed it would miss
the planet by 600,000 miles. Experts say a large bomb could probably be
used to deflect any asteroid heading toward Earth. Don Yeomans, a senior
researcher at NASA's Jet Propulsion Laboratory, said the technology to
do that existed now. ``We would send out a spacecraft with a nuclear weapon
probably,'' Yeomans, who helped decide that XF11 was not going to hit Earth,
said.
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- ``We would set it off one asteroid radius
from the surface. It would slow the asteroid just enough so that in 30
years it would miss the Earth.'' 1997 XF11 would have been a perfect asteroid
to try this on, since scientists had 30 years' notice. ``It is easy to
do if you do it years in advance,'' Yeomans said in a telephone interview.
``If you wait till it's a month away, it would not be possible. A change
of one centimeter per second over 30 years builds up. If you try to slow
it down 30 (centimeters) a second a month before, it doesn't work so well.''
The United States has thought of this in the past. In 1994 the tiny spacecraft
Clementine was due to fly-by the asteroid Geographos after taking pictures
of the Moon, but the mission was scrapped after a mishap sent it out of
control. Last October, President Bill Clinton used his line-item veto to
cut several projects, including ``Clementine II'', which would have sent
spacecraft out to three asteroids. On Thursday Wisconsin Representative
James Sensenbrenner issued a statement calling on Clinton to reinstate
the program. ``This project would have been a low-cost proof of concept
for any future attempt to protect our planet from an asteroid collision,''
Sensenbrenner, who chairs the House Committee on Science, said.
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- Yeomans, who helped the Department of
Defense identify the three target asteroids, agrees, and hopes Clementine
will be resurrected. It would, he said, be a perfect test of how to deflect
a killer asteroid. ``We were going to fly by a couple of asteroids and
smack them with a couple of miniature probes,'' Yeomans said. The probes,
which he described as ``kinetic kill vehicles'', would fly from a mother
ship. ``They would be little mini-spacecraft with cameras on board and
thrusters on board to let them hit,'' Yeomans said. There are other reasons
to fly out to asteroids. Jim Benson, who chairs SpaceDev, based in Steamboat
Springs, Colorado, sees business opportunities. ``Any asteroid a mile or
more in diameter such as XF11, even a stony asteroid (the most deficient
in valuable minerals), contains natural resources that if found on earth
would have a value of more than a trillion dollars,'' Benson said in a
statement.
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- Benson is planning to launch the Near
Earth Asteroid Prospector (NEAP) in 1999 or 2000. It will carry three of
its own instruments to analyze the asteroid's size, and determine its composition
and value. The company is also advertising space for additional experiments.
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