Shuttles 'ready to go fly'

[Guest Glenn]

Source: Reuters

 

June 26, 2005

 

CAPE CANAVERAL: NASA is proceeding with plans to launch Discovery next month on the first shuttle mission since the Columbia accident after examining the risk that falling ice could damage the spacecraft.

 

"I believe our concerns are put to bed and we're ready to go fly," said John Muratore, manager of the space shuttle engineering and integration office.

 

The decision followed a meeting at the Kennedy Space Centre to review engineering analysis of the potential implications of ice falling off the external fuel tank and striking the shuttle during launch.

 

More than 150 engineers and managers, including NASA Administrator Michael Griffin, attended the meeting, NASA spokesman Bruce Buckingham said.

 

Columbia and its crew of seven were lost in February 2003 because a piece of foam insulation fell off the fuel tank during liftoff and damaged the ship's wing.

 

As the shuttle attempted to return to Earth 16 days later, Columbia was torn apart in the upper atmosphere.

 

After the accident, NASA honed in on problems with the tank's insulating foam and changed how and where it was applied. As the agency prepared to return the fleet to flight in May, as originally expected, concerns ice could be just as damaging as foam began to surface.

 

"We started out thinking that debris impact was debris impact," Muratore said.

 

But tens of millions of computer simulations showed ice impacts create deep, narrow cavities and foam creates shallow, wide craters, he said.

 

The danger of either impact affecting the shuttle depended on dozens of factors, including where the shuttle was hit and on environmental conditions, Muratore said.

 

Ice can build up on the outside of the tank once it is filled with supercold liquid oxygen and liquid hydrogen - the propellants used by the shuttle's three main engines. The tank is fuelled about six hours before launch.

 

Before NASA clears the shuttle for flight, officials measure the ice buildup. Since the Columbia accident, NASA has tightened the criteria it uses to determine how much ice buildup is acceptable, shuttle program manager Bill Parsons said.

 

Managers decided in April to delay Discovery's liftoff to add an extra heater to a particularly vulnerable area near the top of its tank. The heater is intended to prevent ice formation in the liquid oxygen feedline bellows. Following the meeting, managers decided no other changes would be necessary.

 

Parsons said he saw no major technical issues that would prevent Discovery's launch as planned between July 13 and 31.

 

An oversight panel monitoring NASA's compliance with the recommendations of the Columbia Accident Investigation Board for the shuttle's safe return to flight is scheduled to meet in Washington on Monday for a final review.

 

NASA managers are to spend two days next week reviewing all of Discovery's flight preparations and set a launch date.