Scientists have designed a "gravity tractor" to save the Earth from an asteroid collision.
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.
Nasa, the US space agency, is so concerned that it has established an expensive monitoring programme to track every object in the sky that might come close to the planet.
It estimates there are more than 100,000 asteroids orbiting near the Earth that are large enough to destroy a city. So far the agency has only been able to identify and track 6,363 of them.
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.”
ust one football pitch-sized asteroid would be capable of obliterating a large city and could cause widespread destruction by also throwing flaming material into the atmosphere and triggering tidal waves.
In 1908, a meteor of this size exploded above Lake Tunguska in Siberia, destroying 770 square miles of forest. Such collisions hit the Earth every 100 years.
To avoid such a disaster, engineers at space company EADS Astrium, which designs and builds spacecraft for Nasa and the European Space Agency, have designed the gravity tractor.
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.
In 2004 an asteroid known as Apophis caused concern after it was calculated to pass alarmingly close to the Earth.
Projections of its path around the sun predicted it had a one in 37 chance of hitting the planet in 2029 – the highest threat in recorded history.
The threat of a 2029 collision was later ruled out but scientists fear that the asteroid could still pass through a key point in space known as a “keyhole” that would put it on course to collide with the Earth in 2036.
“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 plans, said
Kevin Yates, project manager for the UK Near Earth Object Information Centre which is responsible for warning UK ministers of risks from asteroids and comets, said: “Gravity tractors are a solution that are growing in popularity.
“There does need to be international agreements on how to tackle a threat from an asteroid.
“There are all sorts of political difficulties if, for example, a mission only managed to move the point of collision on the Earth from one country to another.”
