NASA’s Kepler space telescope, designed to find Earth-sized planets in the habitable zones of sun-like stars, has discovered its first five exoplanets, the U.S. space agency announced Jan. 4 at the American Astronomical Society meeting in Washington.

Launched in March 2009 from Cape Canaveral, Fla., aboard a Delta 2 rocket, the planet-hunting Kepler spacecraft began last May continuously observing a field of more than 150,000 stars looking for dips in brightness that occur when temporarily obscured by transiting planets.

The five newly discovered exoplanets, named Kepler 4b, Kepler 5b, Kepler 6b, Kepler 7b and Kepler 8b, range in size from similar to Neptune to larger than Jupiter, orbit their stars in 3.3 days to 4.9 days, and likely have temperatures between 1,500 degrees Celsius and 1,900 degrees Celsius, according to NASA. The discoveries are based on approximately six weeks’ worth of data collected since Kepler science operations began last spring.

Built by Boulder, Colo.-based Ball Aerospace & Technologies Corp. for NASA’s Jet Propulsion Laboratory and Ames Research Center, Kepler is expected to continue science operations until at least November 2012. Ames is responsible for Kepler’s mission operations and science data analysis.