The Kepler spacecraft and its Delta II rocket have been cleared to launch into space late Friday night following a thorough review by launch managers Monday.

Liftoff is scheduled for 10:49 p.m. EST. The Launch Services Program was joined by officials and engineers from the United Launch Alliance, the Kepler program and others to examine all aspects of the observatory and the launcher.

Press Conference/Science Briefing

NASA officials and members of the Kepler launch team will discuss Kepler's mission and launch readiness during a press conference beginning at 1 p.m. Thursday. Ed Weiler, NASA's associate administrator for the Science Mission Directorate, heads the panel that also includes Launch Director Omar Baez. A science briefing by the researchers who will analyze the Kepler's findings will follow the press conference. Both events will be televised on NASA TV.

› Watch Pre-launch Press Conference on NASA TV (Thursday @ 1 p.m. EST)

› Multimedia for Feb. 19 Press conference
› Launch Processing Images

The Kepler spacecraft will watch a patch of space for 3.5 years or more for signs of Earth-sized planets moving around stars similar to the sun. The patch that Kepler will watch contains about 100,000 stars like the sun. Using special detectors similar to those used in digital cameras, Kepler will look for slight dimming in the stars as planets pass between the star and Kepler. The Kepler's place in space will allow it to watch the same stars constantly throughout its mission, something observatories like Hubble cannot do.