Friday, March 18, 2011

Nasa to shoot lasers at space junk around Earth to prevent collisions with satellites


  • Nasa fears ‘Kessler Syndrome’, where there is too much space junk for it to be safe to fly out, leaving us trapped on Earth
Nasa is considering using lasers to deflect space junk around Earth and stop it colliding with satellites.
Lasers similar to those used for welding in car factories would be fired through telescopes to ‘nudge’ piles of rubbish left in orbit.
The gentle movement would stop them from taking out communications satellites or hitting the International Space Station.
Crowded: An artist's impression of space junk in low-Earth orbit. Nasa is considering using lasers to deflect the debris and stop it colliding with satellites
Crowded: An artist's impression of space junk in low-Earth orbit. Nasa is considering using lasers to deflect the debris and stop it colliding with satellites
The process could also avoid what is known as ‘Kessler Syndrome’, where there is too much space junk flying around Earth for it to be safe to fly out, leaving us trapped on our own planet.
Such a situation has been predicted by Nasa for more than 30 years and a string of recent near-misses have added urgency to the need to find a solution.
 
Now a team led by Nasa space scientist James Mason have claimed that gently moving junk off course could be the answer.
The theory is that the photons in laser beams carry a tiny amount of momentum in them which, under the right circumstances, could nudge an object in space and slow it down by 0.04 inches per second.
By firing a laser at a piece of junk for a few hours it should be possible to alter it’s course by 650ft per day.

WHAT IS SPACE JUNK?

Australian farmer James Stirton stands next to a ball of twisted metal, purported to be fallen space junk, on his farm in Queensland, Australia
Since the first object, Sputnik One, was launched into space 53 years ago, mankind has created a swarm of perhaps tens of millions of items of debris.
The rubbish circling the planet comes from old rockets, abandoned satellites and missile shrapnel.
It is estimated that there are 370,000 pieces of space junk floating in Earth's orbit.
The picture above shows a ball of twisted metal, thought to be fallen space junk, on a farm in Queensland, Australia, in 2008.
While that won’t be enough to knock it out of orbit, it could be sufficient to avoid a collision with a space station or satellite.
The theory marks a change in approach from previous research which looked into using expensive military Star Wars-style lasers to destroy space junk.
The new project uses equipment that is available for just $800,000 (£500,000) with the final bill coming to just tens of millions of dollars.
Existing telescopes could even be modified, bringing the cost down further.
Nudging would also be more accurate and it is thought the process could divert up to half of all space junk.
Some 20,000 pieces of rubbish are currently being monitored in low-Earth orbit, the majority of which are discarded bits of spacecraft or debris from collisions.
Serious accidents in recent years included the 2009 smash between the Iridium 33 satellite and the Kosmos 2251 satellite.
The communications vessels collided at more than 3,000m per second - the first major smash between two operational satellites in Earth orbit.
Nasa engineer Creon Levit said it was imperative that something was done about space junk.
‘There’s not a lot of argument that this is going to screw us if we don’t do something’ he told Wired.
‘Right now it’s at the tipping point … and it just keeps getting worse.’