Engineers at the University of Strathclyde in Glasgow think they
have the perfect plan to deflect Earth-bound asteroids. They want to
build a flock of tiny satellites that can fly in formation and fire
solar-powered lasers at the giant rock.
So why not just send up one spacecraft carrying a gigantic laser
or a massive atomic bomb or Bruce Willis? Lead researcher Massimiliano Vasile says "our
system is scalable -- a larger asteroid would require adding one or
more spacecraft to the flotilla -- and intrinsically redundant --
if one spacecraft fails the others can continue."
That last point is important, because when the laser begins to
break down the surface of an object, the plume of gas and debris
can mess up the spacecraft and contaminate the laser. Though, Vasile does say that "our laboratory tests have
proven that the level of contamination is less than expected and
the laser could continue to function for longer than
The biggest problem -- which faces both a horde of tiny lasers
and a single multi-megawatt laser cannon -- is that high-powered
lasers in space are still in their infancy. "One of the main
challenges is to have high power, high efficiency and high beam
quality all at the same time," Vasile says.
He, and other researchers, have about two decades years to sort
that out. Asteroid 99942 Apophis
is to make an uncomfortably close call with Earth in 2029, then
swing back around for another flyby on 13 April 2036. Nasa has put
the odds of Apophis hitting Earth at 1 in 250,000.
The research at Strathclyde won't be wasted, though, if 99942
isn't on a collision course with our planet. The team is now
investigating the use of the same concept to remove space debris. The tiny laser flocks could chew up bits of junk,
shove others into safer orbits and generally reduce congestion in
"While there is significant monitoring in place to keep track of
these objects, there is no specific system in place to remove them
and our research could be a possible solution," says Vasile.
"more than 21,000 orbital debris larger than 10 cm are known to
exist. The estimated population of particles between 1 and 10 cm in
diameter is approximately 500,000. The number of particles smaller
than 1 cm exceeds 100 million."