The controllers of NASA flight have declared the final launching time for the NASA’s Kepler spacecraft and its Delta II rocket.

The controllers said that the Kepler space telescope will take off on Friday night at 10:49 p.m. EST from the Exploration Center at NASA Ames Research Center, Moffett Field, California.

The spacecraft, which is named after famed German astronomer Johannes Kepler (1571-1630), will be the National Aeronautics and Space Administration’s primary mission, which will discover earth-like habitable planets in the galaxy.

It will attempt to answer questions such as how many earth-size planets could be there in the galaxy and how many of them are at just the right distances from their suns to have liquid water on their surfaces.

The spacecraft will simultaneously measure the variations in the brightness of over 100,000 stars every 30 minutes, looking for the tiny winks in light output that occur when a planet passes opposite its star. The distance to the majority of the stars for which earth-size planets can be discovered by Kepler ranges between 600 to 3000 light years away.

According to NASA, “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.”