NASA’s planet-hunting space telescope Kepler is slated to launch the night of March 6 from Kennedy Space Center in Cape Canaveral, Florida, on a mission to find Earth-sized planets that could have liquid water at the surface and potentially harbor life.

"It’s not just another science mission. This one has historical significance built into it," said Ed Weiler of the Science Mission Directorate at NASA headquarters. "It very possibly could tell us that earths are very, very common, that we’ve got lots of neighbors out there. Or it could tell us that Earths are really, really, really rare."

For a deeper dive into how Kepler works, check out our mission preview. For live updates on the launch — which is tentatively scheduled for 10:49 pm Eastern, March 6 — follow @NASAKepler on Twitter.

Scientists have found more than 300 planets circling other stars, but none of them look like our pale blue dot. Most of them are gas giants like Jupiter. Others are small but very close to their stars and likely too hot to support life. Current telescopes can’t see with quite enough resolution or sensitivity to detect the tiny change in a star’s brightness that would indicate the presence of an Earth in an orbit in what is known as the habitable zone.

Kepler will change all that.

"We won’t find E.T." said Bill Borucki, the Kepler mission’s principal investigator. "but we might find E.T.’s home looking at all these stars."

Speaking at a press conference, Borucki seemed to want tamp down overheated expectations. He noted that it would be three years before the scientists will be able to say with certainty how common Earths really are.

"But at the the end of that 3 years we’ll get the answer," Borucki said. "Are there other worlds like ours or are we alone?"

Following the failure of the Orbiting Carbon Observatory to reach orbit, NASA officials said this mission did not seem likely to meet a similar fate.

"We learned our lessons from OCO," said Jon Morse, NASA’s astrophysics division director. "The launch services program has done an amazing job since last week pulling together an analysis of any commonality with the previous launch. They’ve given a clean bill of health."

Kepler is going up on a Delta 2 rocket, not the Taurus that OCO used, and doesn’t share many common parts with the failed mission, said Omar Baez, NASA launch director and launch manager at Kennedy Space Center.

"We’re not concerned," he said.

5:22 pm: Updated to correct Taurus/Delta 2 mixup. Also added links for both rocket types.

See Also:

WiSci 2.0: Alexis Madrigal’s Twitter , Google Reader feed, and project site, Inventing Green: the lost history of American clean tech; Wired Science on Facebook.