NASA's just declared its Kepler spacecraft "ready to launch." In case you're not already in the know on this one, the Kepler's mission will be to jaunt out into space, then watch a massive patch of it for 3.5 years to see if there are any signs of habitable planets similar to Earth. The craft will be looking mostly for planets that revolve around stars similar to the Sun, and it will be able to watch about 100,000 of them continuously, unlike the beleaguered but awesome Hubble telescope. The Kepler has a 0.95-meter diameter telescope, and the project has been in the works for about 25 years. It will finally launch tonight, on a Delta 2 rocket. Check out a few images of the Kepler after the break, hit up NASA's Kepler site for the full details of the mission.

[Thanks, Matthew]