Kepler Lifts Off To Find Life In Our Galaxy

Kepler is the world's first mission with the ability to find true Earth-like planets orbiting stars in the "habitable zone."

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 a slight dimming in the stars as planets pass between the stars and Kepler. The observatory's place in space will allow it to watch the same stars constantly throughout its mission, something observatories such as NASA's Hubble Space Telescope cannot do.

Kepler's Mission

The centuries-old quest for other worlds like our Earth has been rejuvenated by the intense excitement and popular interest surrounding the discovery of hundreds of planets orbiting other stars. The Kepler Mission is specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-size and smaller planet and determine the fraction of the hundreds of billions of stars in our galaxy that might have such planets.

The second stage also uses liquid propellants to fuel its engine. The third stage is powered by solid fuel in which the propellants are mixed into a thick substance and ignited.

Kepler will be released on its own after the third stage burns out and separates. The spacecraft will begin its orbit 950 miles above Earth. From that height, it will follow the Earth and slowly drift father away from the planet, basically establishing itself in its own orbit around the sun.

Although the orbital mechanics are extremely technical, scientists are shooting for an orbit that keeps Earth from obstructing the view of Kepler’s telescope as it keeps a steady eye on about 100,000 stars in the Milky Way.

Five Things About Kepler

Here are some quick facts about the Kepler mission, scheduled to launch March 6, 2009:

-- Kepler is the world's first mission with the ability to find true Earth analogs -- planets that orbit stars like our sun in the "habitable zone." The habitable zone is the region around a star where the temperature is just right for water -- an essential ingredient for life as we know it -- to pool on a planet's surface.

-- By the end of Kepler's three-and-one-half-year mission, it will give us a good idea of how common or rare other Earths are in our Milky Way galaxy. This will be an important step in answering the age-old question: Are we alone?

-- Kepler detects planets by looking for periodic dips in the brightness of stars. Some planets pass in front of their stars as seen from our point of view on Earth; when they do, they cause their stars to dim slightly, an event Kepler can see.

-- Kepler has the largest camera ever launched into space, a 95-megapixel array of charge-coupled devices, or CCDs, like those in everyday digital cameras.

-- Kepler's telescope is so powerful that, from its view up in space, it could detect one person in a small town turning off a porch light at night.

Based on NASA provided information.