Extinction by asteroid probably isn't something that keeps most of us up at night. But it does at the B612 Foundation, a nonprofit set up by several former Silicon Valley execs to track and deflect asteroids on a collision course with Earth.

The group is in the process of raising $200 million to build a telescope that will orbit the sun somewhere near Venus, scanning the solar system for Earth-bound asteroids.

If one is spotted, B612 will try to prevent an impact with our planet. But blowing it up Bruce Willis-style isn't a good idea, said Diane Murphy, a spokeswoman for the organization, as that could simply create smaller -- but still problematic -- asteroids. Instead, the group plans to tug it off course using a spacecraft that would fly alongside the rock and exert gravitational pull.

"It's the first deep space mission for the private sector," said Murphy.