NASA calls off Wednesday’s shuttle launch

By Deborah Zabarenko and Irene Klotz

CAPE CANAVERAL, Fla. (Reuters) – NASA on Wednesday delayed
the launch of its first space shuttle mission since the 2003
Columbia disaster after discovering a problem with one of
Discovery’s fuel sensors, NASA’s launch commentator said.

“We will not be able to fly today,” said commentator George
Diller.

Discovery was fueled and ready to launch as planned at 3:51
p.m. EDT (1951 GMT) when the problem with the liquid hydrogen
fuel sensor occurred at 1:32 p.m. (1732 GMT). The sensor is one
of four that detects fuel levels when the tank is nearly empty.

Discovery’s astronauts had just been strapped into their
spaceship when mission controllers called off the launch.

“There are a lot of long faces in the control room,” said
Diller.

NASA did not immediately say how long the delay was likely
to be but called a news briefing for later on Wednesday.

NASA has until July 31 to launch Discovery. After that it
will have to delay until Sept. 9, when the International Space
Station again comes into the right position for a shuttle
rendezvous after a daylight liftoff.

Discovery’s mission is the first shuttle flight since the
Feb. 1, 2003, Columbia disaster, when seven astronauts died as
their shuttle disintegrated over Texas.

COMPLEX SYSTEM

“It is a complex system. Every little part counts,” said
astronaut David Wolf during Wednesday’s broadcast mission
commentary. NASA had problems with the fuel sensors during a
fueling test in April.

The problem was the third technical issue to crop up as the
countdown clock ticked off the hours to liftoff.

A faulty heater delayed the fueling of the external tank
with liquid hydrogen and liquid oxygen by more than an hour on
Wednesday, and on Tuesday, a falling window cover damaged two
heat-resistant tiles near the shuttle’s tail.

The weather on Wednesday had also threatened to prevent the
launch, said NASA weather officer 1st Lt. Mindy Chavez, because
of a 60 percent chance that thunderstorms would occur nearby.

In February, 2003, falling foam knocked a hole in
Columbia’s wing at liftoff, and superheated gases ate into the
breach 16 days later when the spacecraft re-entered Earth’s
atmosphere for landing, causing the craft to disintegrate.

In addition to testing new safety measures introduced after
the Columbia accident, Discovery will deliver much-needed
supplies and equipment to the space station.

The station’s construction has been stalled since the
remaining three-shuttle fleet was grounded after Columbia broke
apart.

Discovery’s flight also heralds the last chapter for the
shuttle fleet, which is set to be retired in 2010 after about
20 construction flights to the station.

NASA’s new administrator, Michael Griffin, said the
shuttles will be succeeded by a new generation of spacecraft
and there is no thought of extending the shuttle fleet’s
service after that. (Additional reporting by Michael Christie)