Solar-Powered Lasers Could Protect Us from an Asteroid Collision
Scientists have discovered that there's a chance that the Apophis asteroid that crosses the Earth's orbit could hit us in 2036 or 2037. We won't know for sure how large that chance is until closer to that time, but scientists at the University of Strathclyde in Scotland haven't wasted any time coming up with a plan to deflect the Apophis or any other asteroids that threaten to hit.
Massimiliano Vasile and Christie Maddock have designed a spacecraft outfitted with solar-powered lasers that would ablate the surface of the asteroid and turn it away from the Earth.
MIT's Technology Review reports:
The basic idea is that the material vaporized from the asteroid's surface, pushes it like rocket exhaust, generating thrust. Until now, space scientists had always thought that a job this size required a megawatt class laser, which would need to be powered by a nuclear reactor.
That introduces a host of challenges, not least of which is launching such a device safely and then dealing with the huge amount of heat it produces.
But Vasile and Maddock say that instead of a single large laser, a better option is to use lots of small ones--kilowatt-class lasers, which could each be powered by the Sun.
The design has a few advantages over other schemes that have been proposed. The solar-powered lasers wouldn't require any on-board fuel and would be safe to launch and the deployment of many small spacecraft armed with them would mean that a few could fail at their mission and there would be others there to get the job done. Another advantage is that the laser beams can be aimed from far away, so there's no risk of vaporized rock coating the spacecraft and creating a host of problems like in other ablation schemes that require the spacecraft to be right alongside the asteroid.
Even if Vasile and Maddock's solar-powered laser idea isn't needed in a couple of decades to guard us against an asteroid, it could be used now to help clean up the large amount of space junk that has amassed in orbit. We've hit a point where the huge amount of debris could start causing a domino-effect of collisions in space. The lasers could be shot at the debris help to lower their orbit. The junk would eventually slow enough to fall toward Earth where it would either burn up in the atmosphere or fall into the ocean.
Dr. Vasile said, “A major advantage of using our technique is that the laser does not have to be fired from the ground. Obviously there are severe restrictions with that process as it has to travel through the atmosphere, has a constrained range of action and can hit the debris only for short arcs.”
We write a lot about solar technologies that will help to protect the planet over the long-term by supplying us with a clean supply of energy, but it's pretty cool to see solar technology that could protect the Earth from a specific, short-term disaster, too, especially when it involves lasers.