[meteorite-list] Could An Asteroid Be Deflected?

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:00:09 2004
Message-ID: <200207241813.LAA28702_at_zagami.jpl.nasa.gov>

http://news.bbc.co.uk/2/hi/science/nature/2148924.stm

Could an asteroid be deflected?
           
Near miss or impact? It is too early to tell
By Ivan Noble
BBC News
July 24, 2002

It will take weeks or even months before astronomers will be able to
confirm their suspicion that asteroid 2002 NT7 will pass very close
to but not hit the Earth early in 2019.

"As further observations accrue, we'll probably find that what is
currently a possible hit will become a near miss," Professor Mark
Bailey, director of the Armagh Observatory in Northern Ireland, told
BBC News Online.

In the very unlikely event that 2002 NT7 did turn out to
be on a direct collision course, astronomers would
have plenty of time to make accurate predictions about
the time and location of the impact, and, with luck, to
come up with a plan to deflect it.

"It's not like dealing with space debris, where the
object may be irregularly shaped and tumbling and
where even hours before impact you don't know
exactly when and where it's going to come down," said
Professor Bailey.

"With an asteroid impact, it's more like when
Shoemaker-Levy 9 hit Jupiter.

"There we were able to calculate the exact time of
impact almost to the second," he said.

Asteroid rendezvous

In the most unlikely event that it were on collision
course, there would be no more important project than
to try to deflect it, he added.

"It orbits roughly every 2.2 years, so there would be
several opportunities to rendezvous with it.

"There'd be opportunity to assess what it's made of,
find out whether it's made of rock and ice, or iron,
whether it's a rubble pile or a solid body.

"It would make sense to put a beacon on it so that
you'd then have a very precise knowledge of its orbit,"
Professor Bailey said.

No-one has yet seriously tried to come up with a plan
to deflect an incoming asteroid, but given years of
warning and an asteroid which orbits relatively
frequently, giving it a small nudge early on might do the
trick.

"Relatively benign deviations imparted years ahead are
magnified each time the asteroid goes around the Sun
and would hopefully be enough to turn a projected
impact into a near miss.

Solar option

"One could even imagine landing on it and firing a
rocket engine.

"People have talked about some kind of a mass driver,
where pieces of rock would somehow be broken off the
asteroid and cast off into space.

"Even a solar sail might be a possibility," Professor
Bailey told BBC News Online.

Such a device might catch the solar wind - a constant
stream of particles emanating from the Sun - and use
the small but significant energy they carry to cause a
tiny deflection in the asteroid's path.
Received on Wed 24 Jul 2002 02:13:42 PM PDT