Kepler Earth Sized planet Hunter Launches Today

The Kepler Planet Hunting mission launches today. H/T Sander Olson.

The Kepler spacecraft will stare at a patch of sky – the same 100,000 stars near the northern constellation Cygnus, all at once – for at least 3-1/2 years. The goal is to detect Earth-like planets orbiting their host stars at distances thought to be sweet spots for life.

If all goes well, Kepler’s journey will start with the launch from Cape Canaveral in Florida at around 10:49 p.m. Eastern time.

The one-ton Kepler observatory boasts a 1.4-meter (4-1/2 foot) diameter mirror and a push-the-envelope camera, according to James Fanson, project manager for the Kepler mission at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. A typical digital camera has roughly eight million to 10 million individual picture elements, or pixels, on its light detector. Kepler’s camera boasts 95 million pixels.

The camera won’t take pictures of the stars it monitors, however. Instead, it will measure changes in starlight as an orbiting planet slips in front of its host star.

Picking the targets, 100,000 sun-like stars, was no cake walk. Astronomers spent five years methodically measuring traits of 4.5 million stars in Kepler’s planned field of view.

Out of the resulting 100,000-star catalog, Kepler scientists estimate that perhaps only 10 percent have planets with orbital periods short enough to allow for repeated detections within Kepler’s 3-1/2 year primary mission length. Some 0.5 percent of the 100,000 stars are expected to reveal planets orbiting at Earth-like distances.

That still means there is potential to find hundreds of Earth-like planets orbiting in that sweet spot. The solar systems range in distance from around 50 light-years away to some 3,000 light-years or more.

Wired has live video feed of the Kepler Launch