NASA's Jupiter Probe Ready for Launch

NASA's Juno spacecraft is getting ready to lift off on Friday, Aug. 5, 2011. On Aug. 4, at about 5 a.m. PDT (8 a.m. EDT), the Jupiter explorer will be rolled some 1,800 feet (about 550 meters) from the 286-foot-tall (87-meter) Vertical Integration Facility, where the Atlas V rocket and Juno were mated, to its launch pad at Space Launch Complex 41 at the Cape Canaveral Air Force Station in Florida.

"Our next move will be much farther - about 1,740 million miles [2,800 million kilometers] to Jupiter," said Jan Chodas, Juno project manager from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The rollout completes Juno's journey on Earth, and now we're excited to be taking our first step into space."

The launch period for Juno opens Aug. 5 and extends through Aug. 26. The spacecraft is expected to arrive at Jupiter in 2016. For an Aug. 5 liftoff, the launch window opens at 8:34 a.m. PDT (11:34 a.m. EDT) and remains open through 9:43 a.m. PDT (12:43 p.m. EDT).

At Cape Canaveral, Atlas V rockets are assembled vertically on a mobile launch platform in the Vertical Integration Facility south of the pad. The mobile platform, carrying Juno and its rocket, will be rolled out to the pad using four 250-ton (227,000-kilogram) rail cars.

When launched, Juno will take almost 11 minutes to reach its temporary orbit around Earth. About 30 minutes later, the Atlas rocket's second stage will perform a second, nine-minute burn, after which Juno will be on its five-year journey to the largest planet in the solar system.