Astronauts aboard the U.S. space shuttle Atlantis began a third day of landing preparations on Sunday, hoping to wrap up their extended 13-day mission to refurbish the Hubble Space Telescope with a Florida homecoming. The crew closed their spaceship's cargo bay doors early on Sunday, aiming for a 10:09 a.m. EDT (1409 GMT) touchdown at the Kennedy Space Center in Florida, Reuters reported. If poor weather precludes a landing, as it did on Friday and Saturday, NASA said it will divert the shuttle to the backup landing site at the Edwards Air Force Base in California's Mojave Desert. The first opportunity for a touchdown in California is at 11:40 a.m. EDT (1540 GMT). NASA kept the seven crew members in orbit an extra two days, hoping for a break in the clouds and rain that have socked in the Florida spaceport. "There's a glimmer of hope," mission commentator Kyle Herring said on Saturday after flight directors decided to make a third try on Sunday. The shuttle is returning from NASA's fifth and final servicing mission to Hubble before the shuttle fleet is retired next year. The observatory, launched in 1990, has provided key evidence of the existence of dark energy, a still-unexplained force that is expanding space at an increasingly faster rate, and the existence of galaxies far earlier than scientists thought possible.
