NASA halts shuttle flights over tank foam problem

By Irene Klotz

HOUSTON (Reuters) – NASA grounded its space shuttle fleet
on Wednesday after learning that large chunks of insulating
foam broke off Discovery’s external fuel tank during launch, an
echo of the problem that doomed sister ship Columbia and its
crew 2 1/2 years ago.

The seven Discovery astronauts were not in danger and the
falling debris does not appear to have hit or damaged their
ship, which took off on Tuesday on a 12-day mission to the
International Space Station, deputy shuttle program manager
Wayne Hale said.

But NASA said it would launch no more shuttles until it
resolves the recurring problem of debris falling off during
blastoff.

“Until we fix this, we’re not ready to go fly again,”
shuttle program manager Bill Parsons said. “I don’t know how
long that is right now. We have a lot of work in front of us to
figure that out and we’re going to go do that.”

Images of the shuttle’s tank, which was jettisoned as
planned just before Discovery slipped into orbit, show at least
three areas where large chunks of insulation foam came off,
Hale and Parsons said.

The finding was troubling because a 1.67-pound (0.75-kg)
piece of foam insulation broke off Columbia’s external tank
during its launch on Jan. 16, 2003, and gouged a hole in the
ship’s wing.

As Columbia attempted to fly through the Earth’s atmosphere
for landing 16 days later, superheated gases blasted into the
breach and tore the ship apart, killing the seven astronauts on
board.

NASA has since spent more than $1 billion improving the
tank and adding other safety upgrades. Discovery’s flight was
the space agency’s first manned mission since the Columbia
accident and was to be the first of two to test the new gear.

“We thought we were safe to fly as is,” Parsons said.
“Obviously we were wrong.”

The largest of the three missing chunks of foam was about
the same size as the one that hit Columbia, but “the video
clearly shows that it fell away and did not strike the
orbiter,” Parsons said.

Engineers were also looking at two areas on the shuttle’s
belly where pieces of the ship’s heat-resistant tile were
missing.

Discovery was on schedule to dock at the International
Space Station on Thursday to deliver critical supplies and
practice heat shield repair techniques during a series of
spacewalks.

The Discovery astronauts spent Wednesday inspecting their
ship with the shuttle’s new laser-scanning boom and will be
asked to have another look at the suspect areas on Thursday.

Members of the space station crew were to take additional
pictures of Discovery during a specially designed flip maneuver
prior to docking.

Preliminary assessments are that Discovery will be safe to
land on Aug. 7, Hale said. He and Parsons said that unlike
during Columbia’s ill-fated mission, NASA has a team of 200
engineers assessing the shuttle’s condition and more
inspections on tap.

Atlantis had been scheduled to launch on the next shuttle
mission in September to resume construction of the
International Space Station before the shuttle fleet is retired
at the end of 2010.