WASHINGTON (AFP) - NASA on Monday launched its Wide-field Infrared Survey Explorer satellite on a mission to orbit Earth and scan the sky in infrared light to photograph the glow of hundreds of millions of objects. The launch, which had been delayed from Friday after problems were discovered in a rocket booster steering engine, went ahead on schedule and flawlessly at 6:09 am (1409 GMT) from Vandenberg Air Force Base in California. WISE will orbit 300 miles (500 kilometers) above Earths surface for six months. It will survey the sky at infrared wavelengths, cataloguing hundreds of millions of objects as it gathers and sends back to Earth information about the solar system, the Milky Way and the universe. By the end of its mission, WISE will have taken nearly 1,500,000 pictures covering the entire sky, NASA said.