Perilous
Times
Asteroid headed for Earth? Give it the laser treatment�
A new study claims lasers would be more effective than bombs in
vaporising an unwanted asteroid
Guardian News and Media Limited
Engineers in Glasgow claim to have found an answer to the danger
posed by asteroids. Photograph:
It is a scenario that has formed the backbone of many a Hollywood
blockbuster. Astronomers spot an asteroid hurtling towards our
planet. Impact is imminent and guaranteed to be catastrophic. Only
Bruce Willis stands between humanity and disaster. Atom bombs,
flown on board space shuttles, are detonated, and at the last
minute the world is saved.
If only it was that simple. In fact, asteroids are poorly
understood objects and deflecting them from earthly impact will be
a lot more difficult than film-makers appreciate. For example, an
atom bomb blast is more likely to pour broken, radioactive pieces
of debris on to us rather than deflecting the object into space.
We will need to be more subtle in our attempts to deal with
encroaching asteroids, say scientists.
Of course, impacts in the near future are extremely unlikely, but
such would be the devastation from one that we need to be properly
prepared, it is argued. And engineers at Strathclyde University in
Glasgow believe they have found an answer to the danger posed by
asteroids. In a paper presented to the Planetary Society last
month, they argue that a swarm of relatively small satellites,
fitted with solar-powered lasers, flying over the surface of an
asteroid could vaporise it much more easily than a large unwieldy
spacecraft, carrying atomic bombs, could do.
"Our approach would involve small satellites, capable of flying in
formation with the asteroid, firing their lasers, targeting the
asteroid at close range," said Dr Massimiliano Vasile, of
Strathclyde's department of mechanical and aerospace engineering.
"We could reduce the threat posed by the potential collision with
small- to medium-sized objects using a flotilla of small, agile
spacecraft each equipped with a highly efficient laser. This is
more feasible than a single large spacecraft. Our system is also
scalable. A larger asteroid would be tackled by adding one or more
spacecraft to the flotilla. It would also have built-in
redundancy. If one spacecraft fails the others can continue."
The use of high-power lasers in space for civil and commercial
applications is still in its infancy, Vasile acknowledges, and
work still needs to be done in building devices that have high
power, high efficiency and high beam quality all at the same time.
Nevertheless, he is confident these issues can be overcome.
Other scientists have warned that zapping asteroids with lasers
would generate plumes of gas and dust that would block the laser
beam. But Vasile rejects the idea that this could be a problem.
"Our laboratory tests have proven that the level of contamination
is less than expected and the laser could continue to function for
longer than anticipated," he added.
Nor are asteroids the only objects that could be usefully blasted
in space, says Vasile. He is investigating the use of satellite
flotillas to remove space debris. The amount of junk � bolts,
spanners, spent rocket motors and other bits and pieces � now
orbiting Earth is growing at an alarming rate. But no one has yet
found an acceptable solution for its removal. Vasile believes the
Strathclyde flotilla could be the answer. "While there is
significant monitoring in place to keep track of these objects,
there is no specific system in place to remove them. Our research
could be a possible solution."