Former Astronaut, Engineers Hope to Deflect Asteroid
http://enews.voanews.com/t?ctl=A7C951:2F72C9DAsteroid could one day strike earth with devastating results,
scientists say
Asteroid 253 Mathilde - Courtesy: NASAHollywood films have dramatized
an event that scientists say could one day happen. An asteroid
approaches the earth, threatening the planet, and a team of daring
astronauts travels to space to stop it. Some scientists and engineers
say the films were not realistic, but that the threat is real.
In the 1998 film Armageddon, Bruce Willis and his team landed on an
asteroid and used a nuclear weapon to destroy it. Scientists say the
movie was not accurate in its science, but that its central premise
was authentic. An asteroid could one day strike the earth with
devastating results.
Trees lay strewn across the Siberian countryside 45 years after a
meteorite struck the Earth near Tunguska, RussiaIn the past 600
million years, collisions with space objects have caused five mass
extinctions. The best-known collision, 65 million years ago, helped
kill off the dinosaurs. But the worst, nearly 200 million years before
that, eliminated more than 90 percent of life on the planet. More
recently, the 1908 explosion of an asteroid over Siberia flattened
2,000 square kilometers of forest.
Two years ago, a group of scientists, engineers, and astronauts
created an organization to prevent another cosmic collision. Called
the B612 foundation, it takes its name from the asteroid that was home
to the fictional Little Prince in the story by French writer Antoine
de Saint-Exupery.
Rusty SchweickartVOA Photo - M. O'SullivanFormer astronaut Rusty
Schweickart, chairman of the foundation, spoke about its goal at the
Planetary Society in Pasadena, California. "To deflect an asteroid in
a controlled manner by 2015. And we're not saying to write a paper
about it, to think about it, to talk about it. We're saying our goal
is to deflect an asteroid, that is, to move an asteroid, to change its
orbit, by 2015," he says.
Mr. Schweickart was the lunar module pilot on the Apollo Nine mission
in 1969, and he is urging the U.S. space agency, NASA, to support the
deflection project.
He says it could be incorporated into an existing NASA program called
Prometheus, which will send a nuclear-powered spacecraft to explore
three of Jupiter's icy moons, and has a scheduled launch date of 2011
or later.
Scientists believe there are more than 1,000 near-earth asteroids at
least one kilometer in size, but the likelihood is low that one that
big will hit earth in the near future. So Mr. Schweickart wants the
demonstration done on a smaller asteroid. "The smaller they are, the
more frequent, therefore we pick not the crowd-killer of a one
kilometer or something like that. It's only going to come once every
million or two million or 10 million years. Instead, we wanted to pick
something that was relatively frequent, a 200 meter object," he says.
A collision of an object of that size with the earth would cause a
blast equivalent to hundreds of megatons of explosives.
Advocates of the project say an asteroid can be deflected to a safer
trajectory with a tiny nudge of less than one centimeter per second,
if the mission is undertaken at least a decade before the projected
collision.
An Asteroid impact destroys Paris in the 1998 film Armageddon -
Courtesy: Touchstone PicturesIn the movie Armageddon, the astronauts
used a nuclear bomb to destroy the approaching asteroid, but that,
says Mr. Schweickart, is not a good idea. Most 200 meter asteroids are
piles of rubble, and one or more of the pieces could hit the planet.
Moreover, says Dan Durda, senior scientist with the Southwest Research
Institute, asteroids are rich in minerals and offer opportunities for
extraterrestrial mining. "You can't mine an asteroid by nuking it. The
same technologies that we're going to be demonstrating or hope to
demonstrate in this particular case to move or deflect an asteroid to
protect the planet, are exactly the same technologies and capabilities
and techniques that we're going to be using to move an asteroid around
the solar system to mine them and utilize them for their resources,"
he says.
It is not likely a large asteroid will collide with earth soon, but
Mr. Schweickart and his colleagues say it is only a matter of time
before one hits us. They add that for the first time in our planet's
history, we have the technology to prevent it.