Spacewalking astronaut repairs heat shield

By Jeff Franks

HOUSTON (Reuters) – Spacewalking astronaut Steve Robinson
plucked a couple of loose fiber strips from Discovery’s belly
on Wednesday in an unprecedented repair to the shuttle’s heat
shield.

“I’m grasping it and I’m pulling it and it’s coming out
very easily. Beautiful. Nice,” Robinson radioed as he pulled
the material out from between the heat resistant tiles on the
shuttle’s underside.

“It looks like this big patient is cured.”

With fellow spacewalker Soichi Noguchi watching from a
perch on the International Space Station, to which Discovery is
docked on the first shuttle flight since the 2003 Columbia
disaster, Robinson was lowered on the station’s robot arm to an
area below Discovery’s nose.

Moving deliberately, he used his gloved fingers to tug out
the two strips with surprisingly little effort. Robinson
carried a small hacksaw, scissors and forceps in case he could
not pull the strips out.

The strips, made of ceramic covered cloth, are thought to
have come loose from their adhesive bond and, though protruding
only an inch (2.5 cm), NASA engineers feared they could change
the aerodynamics enough during landing on Aug. 8 to cause
dangerous heat damage to the shuttle.

Robinson was the first astronaut in the 24-year shuttle
program to spacewalk to a shuttle’s underside and, once there,
the first to fix the heat shield during flight.

He did not appear to damage any of the shuttle’s fragile
tiles. The thin strips in question are each about six inches
long and are placed between the tiles to cushion them.

In a press conference from space on Tuesday, Discovery
astronauts said they initially had misgivings about Robinson’s
spacewalk because they were not convinced it was necessary.
But, they said, they supported it because it seemed an easy
thing to do.

NASA admitted it did not know if the protruding strips were
a danger to the shuttle, but after 2 1/2 years of work and $1
billion spent on safety upgrades since the Columbia disaster,
the agency was taking no chances it could lose another shuttle
to heat damage.

Agency officials said on Tuesday they are even considering
another spacewalk on Friday to fix a protrusion in an
insulating blanket outside the shuttle commander’s window.

Columbia broke apart while returning to Earth on Feb. 1,
2003, because superheated gases penetrated its structure
through a break in the wing heat shield. The seven astronauts
on board were killed.

Columbia’s wing had been struck by a briefcase-sized piece
of insulating foam that shook loose from the external tank at
launch.

Videos showed loose foam swirling from Discovery on its
Aug. 2 launch from Florida, which prompted NASA to ground the
shuttle fleet until the foam problem is finally fixed.

The loose strips on Discovery are not believed to have been
caused by impacts.

The landmark repair job came at the end of the third
spacewalk this mission by Robinson and Japan’s Noguchi. Before
the fix, they attached an external storage platform to the $95
billion space station.