NASA begins moving space shuttle Discovery to launch pad

NASA began moving Discovery to the launch pad Friday in preparation for only the second liftoff of a space shuttle since the Columbia disaster three years ago.

Discovery's trek of a little more than 4 miles (6.5 kilometers) was expected to take about seven hours aboard a crawler-transporter. The shuttle weighs about 4.5 million pounds (2 million kilograms).

Its move to the launch pad is a major step toward a liftoff sometime between July 1 and July 19, reports AP.

"It’s a fabulous feeling to see that we’re rolling Discovery back to the launch pad for our next launch attempt," NASA’s shuttle program manager Wayne Hale told reporters after riding with the orbiter as it left the VAB. "I think we’re on a really good path to make that July 1 window opening day."

Hale said that preliminary results of wind tunnel tests to check changes to Discovery’s external fuel tank – primarily the removal of a foam ramp to reduce debris hazards at launch– are positive, but won’t be final for about three weeks.

"We have to wait until we get to the bottom line," Hale said. "We could be smarter tomorrow and somebody could find out something we need to deal with."

The shuttle's payload – a cargo pod dubbed Leonardo, spare space station parts and other items – arrived at the launch pad Wednesday, NASA officials said, informs Space.

A successful flight will allow NASA to resume construction of the half-built International Space Station and possibly extend the life of the beloved Hubble Space Telescope, which has allowed humans to peer into far galaxies. But with the shuttle fleet due to retire in 2010, any serious problems during July's mission likely would bring a premature end to the shuttle program and disrupt NASA's plans to keep its skilled work force intact, while a replacement spacecraft is being developed, according to SABC News.