Repairs and Need for Rescue Craft Pushed Back Shuttle Timetable

NY Times ^ | February 21, 2004 | WARREN E. LEARY

[neverdem]

WASHINGTON, Feb. 20 — NASA pushed back the time for resuming shuttle flights to next spring because more time was needed to prepare a potential rescue shuttle and to resolve persistent technical problems, like preventing the fuel tank from shedding foam insulation, agency officials said Friday.

William Readdy, NASA's associate administrator for space flight, said engineers had only recently pinpointed why foam fell from the tank of the shuttle Columbia at its launching last year, leading to the shuttle's disintegration upon re-entry on Feb. 1, 2003. The shuttle fleet has been grounded since the accident.

Engineers also discovered a new holdup, a problem in the tail rudder, Mr. Readdy said.

Senior space flight officials therefore decided Thursday to aim for a launching window of March 6 to April 18, 2005, to give the National Aeronautics and Space Administration more time to modify the three-shuttle fleet and to have a backup ship ready in case a rescue is needed for the first crew.

Mr. Readdy said that understanding and resolving the foam problem on the big external tank had taken longer than expected, but that engineers believed extensive testing and computer simulations had pinpointed the trouble.

"Return to flight has always been driven by fixing the tank," he said in a telephone news conference.

Before the Columbia accident, Mr. Readdy said, engineers believed that most foam coming off the tank peeled away and dropped away from the shuttle. Now, NASA engineers have learned how air or nitrogen liquefied by the supercold fuel in the tank can seep into cracks in the foam or collect around nuts and bolts beneath the insulation. This trapped gas expands with enough speed when heated by friction during liftoff that it shoots pieces of foam into the path of the shuttle, which hit it at high speed, causing damage.

"That is really the root cause that we've been able to discover here," Mr. Readdy said.

The tank is being redesigned to change the position of bolts and close areas where liquid air or nitrogen can collect, he said. Engineers are also working on ways to apply the foam to eliminate air pockets and are developing ways to test the foam for flaws after application, he said.

A new holdup is a problem discovered in the tail rudder, which also serves as a speed brake. An inspection of the shuttle Discovery found corrosion on an actuator that operates the brake, Mr. Readdy said, and faulty gear installation turned up on another unit.

NASA decided to remove and inspect the actuators in all three shuttles. Because this work was further along on the Discovery, he said, the agency decided to use that craft on the first flight instead of the Atlantis.

The agency decided not to aim for a January launching for resuming flights because of the brake work and because there would not have been time to have a backup shuttle ready, Mr. Readdy said.

If a shuttle is damaged and its crew has to take refuge in the International Space Station, agency officials said Thursday, they want a second orbiter ready to retrieve the crew in 45 to 90 days.

Mr. Readdy said Thursday that a rescue mission could be launched in as few as 35 days. In this instance, a crew of three or four would pilot the second shuttle to the station and bring back the stranded astronauts. To bring back seven crewmen, some of whom might be injured, NASA may have to design a new floor plate for the shuttle's second deck to accommodate seven reclining seats, he said.

[Interesting Times]

Every single writer at the NY Times would do a full gainer into boiling oil before admitting in print that using "environmentally correct" foam was a major factor in the loss of Columbia.

[neverdem]

Ping, if the title still looks like a URL the story is about NASA's plan for emergency rescue of Space Shuttles in the future. My computer is screwy lately.

[George from New England]

using "environmentally correct" foam was a major factor in the loss of Columbia.

THIS HAS TO BE SAID LOUDER...

IT WAS THE USE OF "ENVIRONMENTALLY CORRECT FOAM THAT WAS THE MAJOR FACTOR IN THE LOSS OF THE COLUMBIA.

There I feel better.

[norraad]

Thank you.

One more time ...

r134a based foam is bad!

r12 based foam is good!