London: British scientists have designed
a spacecraft which they claim is capable of saving Earth from
a catastrophic asteroid collision.
A team at British space company EADS Astrium has made
the spacecraft, "gravity tractor", which will be deployed when
an orbiting rock is detected on a collision course with Earth
-- in fact, it will intercept the asteroid and position itself
to fly alongside it, just 160 feet from its surface.
And, from this position, the ten-tonne craft is able
to exert a small gravitational force on the rock, pulling the
asteroid towards it. By gradually modifying its course, over
several years, the gravity tractor is able to slowly shift the
asteroid's trajectory enough to ensure it misses the Earth.
According to the scientists, the spacecraft could
divert asteroids that are up to 430 yards across -- big enough
to release 100,000 times more energy than the nuclear bomb
dropped by the US on Hiroshima in 1945.
Dr Ralph Cordey of Astrium was quoted by 'The Daily
Telegraph' as saying: "Anything bigger than 30 metres across
is a real threat to the Earth. Unfortunately it is a matter of
when rather than if one of them hits us.
"The gravity tractor exploits the principals of very
basic physics -- every object with a mass has its own gravity
that affects objects around it. It can move fairly large
objects 300 metres to 400 metres across.
"These asteroids are hurtling around our solar system
at 10 km per second, so when you scale that up, you just need
a tiny nudge to send it off course."
The team has designed the gravity tractor and planned
details of the mission. The craft can be built in a relatively
short time, using existing technologies, if an asteroid was
detected on a collision course. But, it's likely that it would
require an international agreement to send a mission in space.
"We've designed the mission using the technology that
we currently have available, so it could be put into practice
at any time," Christian Trenkel, who has worked on the mission
First Published: Sunday, August 30, 2009, 12:46