[meteorite-list] Space-Based Missile Defense Needed to Thwart Asteroid Attacks

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:54:04 2004
Message-ID: <200202141653.IAA07394_at_zagami.jpl.nasa.gov>

http://www.space.com/scienceastronomy/solarsystem/deflection_asteroids_020214.html

Space-Based Missile Defense Needed to Thwart Asteroid Attacks
space.com
By Robert Roy Britt
14 February 2002

Earth is little more than a sitting duck in a cosmic shooting gallery, the
scientists tell us. But that doesn't mean we can't shoot back. If an
asteroid is ever found to have our planet in its sights, a carefully aimed
missile can simply knock the rock off course.

There's one little problem. It's hard to deflect something that's coming
right at you.

Any boxer understands this. A slight bit of energy applied to a punch in the
right way can turn a roundhouse into a harmless glancing blow. But if you
try and stop an upper cut by driving your chin directly into it, you'll go
down for the count.

Claudio Maccone at the Center for Astrodynamics in Turin, Italy, has a
boxer's eye for asteroids, and he's developed what he claims is the best
plan for protecting Earth.

Put missiles in space, Maccone says, and hit the asteroids at an angle.

The targets

Some 587 large, potentially threatening asteroids have been found near
Earth. All are bigger than 1 kilometer (0.6 miles), the threshold for what
most researchers agree could cause global catastrophe. None of these rocks
is on course to hit Earth. But there are about 500 more that have yet to be
found, according to leading estimates.

Most of the remaining large asteroids should be detected by the end of the
decade, NASA experts say. If one is ever determined to be a serious threat,
chances are good there will be a decade or more to deal with it.

But thousands upon thousands of smaller rocks, each capable of destroying a
city or even a state, will likely take much longer to find. Warning time
might be just days or weeks. In one case last month, an asteroid that could
have caused significant damage, and which passed Earth just twice the
distance to the Moon, was first spotted barely a month before it flew by.

While a lot of energy and money goes into finding asteroids, almost no
resources have been devoted to developing a plan of action to deal with one
that could wipe out civilization.

Deft deflection

Maccone says the best defense is a set of five missile launchers. Each would
be located at a so-called Lagrangian point, spots where the gravity of Earth
and the Moon roughly balances out, allowing for a spacecraft to maintain a
nearly stable position.

By taking up posts at each of five Lagrangian points, any incoming asteroid
could be hit at a 90-degree angle, Maccone explains. Little energy would be
required, as when a boxer steps aside and deflects a punch with a deft flick
of the wrist.

Maccone's idea is detailed in the journal Acta Astronautica and was reported
yesterday by New Scientist magazine.

The weapons of choice would be nuclear, however, and Maccone worries in his
journal article that there would be significant political hurdles to getting
any plan approved.

Cold War attitude

"Many people's minds are still too much in the Cold War attitude," Maccone
writes. "Since nuclear weapons in space are forbidden by international
treatises, a proposal to locate missiles with possible nuclear warheads at
the Lagrangian points L3 and L1 would immediately be perceived as an attempt
to revive the Cold War."

Maccone thinks a new collective human conscience will need to emerge before
much will be done to face the threat of asteroids.

"Only when humans will stop planning and conducting big wars among
themselves, will the governments have more time to think about the new
danger coming from space," he said.

Terrorism's role

Regardless of any harmonious cooperation between the world's peoples,
serious plans to protect the planet are not likely to hatch soon. Unless we
get hit.

Benny Peiser, a researcher at Liverpool John Moores University in the UK,
monitors the social, political and scientific issues surrounding the
asteroid threat.

"I doubt whether there will be any international initiatives, let alone
consensus on planetary defense, until we have witnessed another
Tunguska-type cosmic disaster," Peiser told SPACE.com.

Tunguska is the name given to a 1908 explosion of a comet or asteroid about
five miles above the surface of Siberia. The event flattened hundreds of
thousands of forested acres. No one died, because no one lived there. A
similar event over a populated area could easily kill thousands of people.

Peiser figures that a plan like Maccone's would have to be led by the U.S.
Military, which already sees space as a necessary strategic outpost.

The current response to terrorism, Peiser said, "has led the U.S. to
significantly increase the budget for space-based defense paraphernalia
which inadvertently enhances the prospects for advanced planetary defense
technologies."
Received on Thu 14 Feb 2002 11:53:38 AM PST