Space shuttle heads back to Florida launch pad

CAPE CANAVERAL, Florida - Space shuttle Discovery moved back to its Florida launch pad, a critical step in NASA's plan to return its shuttle fleet to flight next month after a hiatus of more than two years.

It was the second trip to the launch pad for Discovery, which had been scheduled for liftoff in May on the first flight since shuttle Columbia disintegrated on re-entry into Earth's atmosphere in February 2003. Instead of heading into orbit, Discovery was brought back to its hangar last month to be outfitted with an upgraded fuel tank.

NASA is aiming to launch Discovery between July 13 and July 31. 

The 4.2-mile trek from the Kennedy Space Center's assembly building to the seaside launch site took several hours longer than expected, due to four stops to check temperatures in a bearing on the shuttle's crawler-transporter, Kennedy Space Center spokeswoman Tracy Young said.

The Apollo-era crawler moves at a top speed of 1 mph (1.6 kph), though it averaged less than half that speed for the trip.

Managers still do not know if an extra heater installed near the top of the shuttle's fuel tank will be enough to dispel concerns that ice could form once the tank is fueled for liftoff. The ice could break off during launch and strike the shuttle.

Preventing impacts on the orbiter during launch has been NASA's primary safety focus since the loss of Columbia.

Columbia was fatally damaged by a piece of foam insulation that fell off the fuel tank and hit the shuttle's wing during launch. The damage triggered the ship's destruction and the deaths of seven crew members 16 days later as Columbia attempted to fly through the atmosphere for landing.

The final determination on whether the shuttle is ready to fly will be made by June 30. A review of debris-impact risks is scheduled to be presented to NASA managers on June 24.

"Until the (debris-impact) analysis is done completely we will not know exactly what the situation is for the next flight," said Joseph Cuzzupoli, a member of the task force assigned to oversee the US space agency's return-to-flight effort.

"We should probably have started the ice debris (analysis) earlier than we did," Cuzzupoli said last week. "Foam is understood now and ice isn't and we started maybe too late. But right now we're catching up."

- REUTERS