CAPE
CANAVERAL, Fla. - For the second
time in two weeks, the seven-astronaut crew of the space shuttle Discovery flew
into NASA's Florida spaceport Friday as they prepare for a July 26 launch.
"This would
be a great day for a launch," veteran
astronaut Eileen Collins, commander of Discovery's STS-114 mission, told reporters here at Kennedy Space Center's Shuttle Landing
Facility. "We're hoping that this
weather holds through next week."
Collins eased her
T-38 jet to a stop on the tarmac at about 11:45 a.m. EDT (1545 GMT). At the same time, Discovery pilot
James Kelly halted his own T-38 aircraft with mission specialist Charlie
Camarda in the back seat. STS-114 mission specialist Wendy Lawrence accompanied
Collins during the flight from Houston, Texas, where the astronaut conducted an
ascent/entry training simulation Thursday.
The arrival
of some STS-114 astronauts was delayed. NASA officials said that the T-38
aircraft carrying STS-114 mission specialists Andrew Thomas, Soichi Noguchi and
Stephen Robinson had to return to Ellington Air Force Base to switch planes after
they developed some in-flight problems.
"We had
some mechanical problems with a couple of the planes," Thomas said. "We always
have back ups with us and just swapped out."
Collins and
her fellow Discovery astronauts are slated to launch
spaceward at about 10:39 a.m. EDT (1439 GMT) on July 26. Their flight has been
delayed since July 13, when launch controllers scrubbed
the attempted space shot after a liquid hydrogen fuel sensor failed a standard
countdown test. Since then, engineers have worked around the clock to isolate
and fix the glitch, and are targeting two potential sources that include
electromagnetic interference from cameras, heaters or other hardware aboard
Discovery and its external tank, as well as a grounding issue with wiring
aboard the orbiter.
"We are
very proud of the work that the engineers, technicians and managers have done
to try and figure out this problem," Collins said, adding that she and her crew
have been listening in on technical briefings and following the troubleshooting
efforts.
Engineers
have been tracing
a glitch in the engine cut-off (ECO) sensor system inside the liquid hydrogen
compartment of Discovery's external tank. One of the four sensors failed to
properly report a 'dry' status - indicating the tank was empty of fuel - during
a countdown test. Under current flight rules, all four sensors are required to
perform properly since they ensure Discovery's three main engines shut down
before its fuel tanks run dry. If the engines continue firing once the tank is
empty, they could rip apart the shuttle.
The STS-114 astronauts are NASA's first slated to ride a shuttle into orbit since the 2003 Columbia disaster that claimed the lives of seven astronaut and destroyed one orbiter.
While the
engineering investigation has pushed Discovery's launch further into its flight
window - which closes on July 31 - Collins said that safety,
not scheduling, is paramount.
"The launch
date, to us, isn't that important...what's important to us is that we get through this process
and do it right," Collins said. "We're really excited about getting this launch off. We'll
be talking to you from space."
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