A new telescope specifically designed to find Earth-sized planets around other stars  has been scheduled for a June 2008 launch.

The Kepler telescope will observe slight dips in brightness that occur when a planet passes in front of its parent star. It will spend four years focusing on one region of the galaxy, and monitor the brightness of 100,000 stars. The telescope will be stationed behind the Earth in a heliocentric orbit. Gradually, it will drift farther behind the Earth, eventually reaching a distance of 75 million kilometers (about 47 million miles).

Kepler's main mirror was made by an Pittsburgh optics company L-3 Communications Brashear. At a diameter of four and a half feet (1.5 meters), it is the largest mirror ever built for a space mission traveling beyond Earth orbit. It has been delivered to Ball Aerospace the Boulder, Colorado company responsible for the spacecraft's assembly.