Fuel glitch may not stop shuttle launch, says NASA

By Irene Klotz

CAPE CANAVERAL, Fla. (Reuters) – NASA is prepared to launch
its first space shuttle mission since the Columbia accident
2-1/2 years ago even if a technical glitch that grounded
Discovery on July 13 reoccurs, the U.S. space agency said on
Sunday.

The launch of Discovery is scheduled for 10:39 a.m. EDT
(1439 GMT) on Tuesday, and is under intense scrutiny because of
safety upgrades and other changes implemented after Columbia
fell apart over Texas in February 2003, killing seven
astronauts.

“I think what you want coming out of the Columbia accident,
the loss of Columbia and the soul-searching examination that
NASA has undertaken since then, what you want of NASA is that
we make the right technical decisions, that we do the right
thing to the extent that we can figure that out, which is
hard,” said NASA administrator Michael Griffin.

“We can’t restrict the range of our options to those things
which are going to present well necessarily,” he said.

NASA flight rules require all four of the shuttle’s
hydrogen fuel sensors to be working before liftoff.

The instruments would shut down the shuttle’s main engines
before they run out of hydrogen fuel to avoid a potentially
catastrophic explosion. The engine shutdown would occur if two
of the four sensors register an empty tank.

When one sensor failed a routine prelaunch test during
Discovery’s first launch attempt on July 13, managers canceled
the flight. Exhaustive tests, however, failed to reveal the
cause of the glitch.

Technicians did find and fix three subtle electrical
grounding issues with equipment that feeds the sensor data to
an electronics box in the shuttle’s aft engine compartment.

“It is possible that we have caused the problem to go
away,” shuttle deputy program manager Wayne Hale said.

Managers also swapped the suspect sensor’s connector with
another sensor so that if the problem reoccurs, engineers will
have more information about whether the sensor itself, the
wiring or the electronics box is at fault.

If the tests assure managers that the problem is isolated
to a single sensor, NASA plans to waive its flight rule and
launch the shuttle, provided all other systems and the weather
is acceptable for launch.

‘GHOSTS OF COLUMBIA’

“If it reoccurs we think we have a really good
understanding and really good plan to go forward with,” Hale
said.

“I wake up every day and I ask myself ‘Are we pushing too
hard? Are we doing this thoroughly? Have we done the right
technical things? Have we asked the right people? Have we built
the tests properly?’

“I think we are all still struggling a bit with the ghosts
of Columbia and therefore we want to make sure we do it right,”
Hale added.

Shuttle Columbia was destroyed during a landing attempt on
Feb. 1, 2003. A piece of foam that fell off the shuttle’s fuel
tank during launch had damaged the ship’s wing, and as it flew
through the atmosphere for landing, superheated gases blasted
into the hole.

NASA had long overlooked what effect debris could have on
the shuttle. Managers said they are not making the same mistake
by preparing to change a flight rule to launch Discovery.

“Our team is making a clear point that they are not
brushing away unexplained factors and saying they don’t
matter,” Griffin said.

“They are reducing the issue to a situation where there are
two or three unexplained and, at this point, unexplainable
possibilities that we simply won’t find until we tank up and
test,” he said.

(Additional reporting by Michael Christie)