Instead of bemoaning the fact that there are no viable methods on Earth for us to protect ourselves from an asteroid strike, some scientists are proposing to be a lot more proactive by building a "realistic" method for mitigating those potential threats.
A physicist from UC Santa Barbara, Philip M. Lubin, and a researcher from CalPoly San Luis Obispo, Gary B. Hughes, along with several undergrad students, are working on a project called DE-STAR, or "Directed Energy Solar Targeting of Asteroids and exploRation", which may develop into a space-based defense system for near-earth asteroids and comets.
Lubin, who has been working on the project for about a year, explains the rational behind it this way:
"We have to come to grips with discussing these issues in a logical and rational way. We need to be proactive rather than reactive in dealing with threats. Duck and cover is not an option. We can actually do something about it and it's credible to do something. So let's begin along this path. Let's start small and work our way up. There is no need to break the bank to start." - Philip M. Lubin
According to the project team, their proposed system would use "a massive phased array of laser beams" to destroy or deflect asteroids that would pose a threat to the planet. The DE-STAR is said to be capable of destroying an asteroid 10 times the size of the one that recently came close, 2012 DA14, with 100 gigawatts of laser power.
This system sounds like it belongs in the sci-fi or vaporware category of ideas, but one of the researchers says that DE-STAR is based on what is essentially current technology, and is really not that far off:
"All the components of this system pretty much exist today. Maybe not quite at the scale that we'd need –– scaling up would be the challenge –– but the basic elements are all there and ready to go. We just need to put them into a larger system to be effective, and once the system is there, it can do so many things." - Gary B. Hughes
The proposed system is said to be possible of being used as a giant orbiting power source, for assessing the mineral composition of asteroids, for planetary exploration, or even as a spacecraft propulsion system. While all of that may sound like it would take a miracle to develop, according to Hughes, the project's viability is based on "detailed analysis, through solid calculations", not just estimates and conjecture.