To combat a space-based threat, try a space-based solution. Within the next six years, the B612 Foundation plans to launch the Sentinel Mission – a dedicated infrared telescope that will be on the lookout for killer asteroids.

The project will be the first privately funded deep space mission and will greatly expand the catalog of known near-Earth objects. The foundation estimates it will cost several hundred million dollars to build the telescope and hopes it will be ready to go by 2017.

While large comets and asteroids strike the Earth infrequently – the last major one killed the dinosaurs 65 million years ago – they are a potential hazard. An object larger than half a mile across could cause global climate shifts and mass extinctions. Smaller rocks around 200 feet in diameter could easily level a city.

Several ground-based telescopes and projects, such NASA’s Near-Earth Object program, have eyes on the sky to search for potentially hazardous space rocks under the aegis of the Spaceguard Survey. Collectively, they have detected nearly 10,000 objects and an estimated 90 percent of near-Earth asteroids larger than a half mile.

Near Earth, there still lurk about half a million asteroid larger than the one that cause the 1908 Tunkusga event, when a large object from space exploded over Siberia, destroying a zone roughly equal to the San Francisco Bay Area.

“That’s the urgency of this,” said Ed Lu, a chairman of the B612 Foundation and former space shuttle astronaut. “If there is an asteroid out there that may strike in the next 10 or 20 years, then time’s a wastin'.”

The company currently plans to launch their telescope on a SpaceX Falcon 9 rocket, sending the spacecraft toward the inner solar system into a gravity assist slingshot around Venus. The roughly 25-foot telescope will orbit the sun from between 0.6 and 0.8 times the Earth-sun distance and is planned to have a 5.5-year initial mission to find 90 percent of asteroids larger than 500 feet. It also intends to map out a significant number of 100-foot-diameter asteroids.

After launch, the telescope will immediately begin to search for near-Earth objects and calculate their orbits, making sure that none of them intersect with Earth’s. Being a dedicated asteroid-finding mission and working from space will give it a tremendous advantage over ground-based telescopes. Within a month, Lu calculates that the telescope will find 16,000 objects, more than doubling the known catalog. Ultimately, he hopes to expand the number of known asteroids by a hundred-fold.

The project will release asteroid trajectories publicly through an existing network that includes the Minor Planet Center in Cambridge, Massachusetts. Many researchers are eager to get their hands on such data. At a conference the B612 Foundation held last year, roughly 50 interested scientists gathered to discuss near-Earth asteroid threats.

Though such a project has been suggested in the past, NASA has never seriously considered a dedicated asteroid-hunting space telescope, and this is not likely to change in the current tight budget climate. Lu said that developments in processing speed and hardware over the last 10 years, as well as the emergence of private spaceflight companies, have made it possible for a private non-profit to step in and take the project on.

He compared the estimated hundreds of millions of dollars they need to the amount necessary to build a metropolitan museum or performing arts center. While the project is ambitious, it doesn't require the potentially billions in funding and decades of development needed for the risky asteroid mining venture recently proposed by Planetary Resources, Inc.

If a potentially dangerous asteroid is ever detected, there could be an international effort from space agencies to deflect it by slamming a large counterweight into it, using a gravity tug, or roping it with giant lasso.

A major component of the Sentinel Mission will be public education and outreach, said Lu. The foundation hopes to work with schools and museums to involve students and members of the public – perhaps through some sort of citizen science project – and help inspire future generations to get into science and engineering. They hope to show people that such a project is possible with the technology at hand.

In addition, data from the telescope will map out the near-Earth environ, potentially aiding in future exploration, robotic or manned.

“That’s why this isn’t a fear-mongering message,” said Lu, “It’s an empowering message – let’s just go it.”

Images: 1) The proposed orbit of the B612 Foundation's Sentinel telescope, which will search for hazardous near-Earth asteroids. 2) Mock up of the telescope's design. B612 Foundation