/ 30 December 2009

Russia’s plan to save Earth from collision with asteroid

Space scientists in Russia are preparing to boldly go where no man has gone before, except for the actor Bruce Willis.

The head of the Russian space agency said on Thursday that it was considering a Hollywood-style mission to send a spacecraft to bump a large asteroid from a possible collision course with Earth.

Anatoly Perminov told the Russian radio station Golos Rossii: “People’s lives are at stake. We should pay several hundred million dollars and build a system that would allow us to prevent a collision, rather than sit and wait for it to happen and kill hundreds of thousands of people.”

The mission would be aimed at an asteroid called Apophis, he said, which is expected to pass close to the Earth in 2029 and again in 2036. “Calculations show that it’s possible to create a special-purpose spacecraft within the time we have, which would help avoid the collision. The threat of collision can be averted.”

The Hollywood action films Deep Impact and Armageddon both featured space missions scrambling to avert catastrophic collisions, the latter led by Willis.

But the creation of a system to deflect asteroids has long been the subject of scientific debate. Some experts have proposed sending a probe to circle around a dangerous asteroid and gradually change its trajectory. Others suggested sending a spacecraft to collide with it and alter its momentum, or using nuclear weapons.

Perminov said details of the project still needed to be worked out. But he said the agency would invite Nasa, the European Space Agency and others to participate.

When Apophis was discovered in 2004, astronomers made headlines when they said there was a one in 37 chance that the 350-metre-wide rock would collide with Earth in 2029. Further studies ruled out such an impact, but there remains a one in 250 000 chance it could strike in 2036.

Perminov said he had heard from a scientist that Apophis is getting closer and may hit the planet. “I don’t remember exactly, but it seems to me it could hit the Earth by 2032,” he said.

Nasa has estimated that if the asteroid hit the Earth, it would release more than 100 000 times the energy released in the nuclear blast over Hiroshima. Thousands of square kilometres would be directly affected by the blast but the whole of the Earth would see the effects of the dust released into the atmosphere.

Nasa experts have already discussed the option of landing an astronaut on an asteroid to test whether it could develop techniques to deflect a doomsday rock.

Breaking it up with an atomic warhead could generate thousands of smaller objects on a similar course, which could have time to re-form. Scientists agree the best approach, given enough time, would be to nudge the object into a safer orbit.

Matt Genge, a space researcher at Imperial College London, has calculated that something with the mass, acceleration and thrust of a small car could push an asteroid weighing a billion tonnes out of the path of Earth in just 75 days.

Perminov said: “We will soon hold a closed meeting of our collegium, the science-technical council, to look at what can be done. “There won’t be any nuclear explosions. Everything will be done according to the laws of physics.”

Mirrors, lights and even paint could change the way the object absorbed light and heat enough to shift its direction over 20 years or so. With less notice, mankind could be forced to take more drastic measures, such as setting off a massive explosion on or near the object to change its course. – guardian.co.uk