CAPE
CANAVERAL, Fla. - With the space shuttle Discovery back on Earth and its astronaut
crew safe and sound, NASA is commending the successful spaceflight--the space
agency's first since the Columbia accident--while admitting that more work
remains to be done.
"Obviously,
we're real pleased," NASA chief Michael Griffin told reporters in a
post-landing briefing. "This is the first step back [into] our return to flight
sequence."
Discovery
and its STS-114 crew, commanded by veteran astronaut Eileen Collins, landed
Tuesday at 8:11:22 a.m. EDT (1211:22 GMT), rolling to a stop on a concrete
runway at Edwards Air Force Base in California. At 10:14 a.m. EDT (1414 GMT),
Collins and her crewmates cracked Discovery's outer hatch and stepped back onto
terra firma.
"We have
had a fantastic mission," Collins said from the tarmac of Edwards' Runway 22
after Discovery's landing. "We are so glad to come back and be able to say it's
a success."
But Griffin said that shuttle engineers and managers will take their time analyzing the data from
Discovery's STS-114 mission, such as launch images and video depicting large pieces
of insulation foam popping of the orbiter's external tank.
"We don't
like that," Griffin said. "That's the only thing that went wrong with this
mission in any significant way."
The foam
debris--which brought back memories of the lost Columbia mission--clouded a
spaceflight in which the STS-114 astronauts performed flawlessly, Griffin added.
Launched
on July 26, Discovery's STS-114 mission was NASA's first shuttle flight since
the 2003 Columbia
disaster, which destroyed one orbiter and killed seven astronauts. Columbia
broke apart while reentering the Earth's atmosphere on Feb. 1, 2003. Its
STS-107 astronaut crew did not survive.
Investigators
later traced the accident's cause to a 1.67-pound piece of external tank foam
that fell from Columbia's external tank during launch and struck the orbiter's
left wing. The impact pierced Columbia's heat shield, leaving the spacecraft
vulnerable to the searing heat of reentry and hot gases that entered the wing
and ultimately destroyed the shuttle.
"I'll never
forget where I was when we lost Columbia," Griffin said, adding that the
memories of lost astronauts were strong today. "I will never be able to forget
where I was when we lost Challenger; I had a couple of friends on that flight."
STS-114 was
tagged as NASA's first of two test flights to evaluate new tools and techniques
to enhance shuttle flight safety and prevent another Columbia-type accident.
The 14-day spaceflight, lauded by astronauts and mission managers as wildly
successful, delivered tons of vital supplies and equipment to the International
Space Station (ISS), as well as tested three heat shield repair methods,
installed new space station hardware and included the first-ever orbital repair
of a shuttle's tile-covered belly by an astronaut.
"Eileen
made it look like a cakewalk," NASA's space operations associate administrator
William Readdy said of the conclusion of STS-114.
Readdy
added that NASA's second return to flight mission, STS-121 aboard Atlantis,
will pick up where Discovery left off.
"It's going
to be really hard to top this mission," Griffin said.
A
problem resurfaces
Marring the
apparently spotless record of Discovery's successful STS-114 flight is the foam
debris loss seen during the shuttle's launch.
NASA guided
much of its return to flight effort and about $200 million to reduce foam
shedding during launches to harmless proportions. What was missing was a flight
test, Griffin said, which engineers now have from Discovery's launch.
Imagery and
video from new cameras aboard Discovery's external tank, the orbiter itself and
ISS crew photography found evidence of at least five instances of unacceptably
large foam pieces separating from the tank, NASA officials said.
"I think
that now it's clear what it is that we need to go work on," said Bill Parsons,
NASA's space shuttle program manager. "Today we honored the Columbia crew;
we've brought the Discovery crew home safe."
Some of the
foam debris seen in Discovery's launch fell from ramp largely coated in
hand-applied foam, a region that engineers had questions but ultimately
believed was safe. Griffin has assigned a "tiger team" to study the issue, but
whether the foam debris problem can be solved in time to mean the Sept. 22
opening of Atlantis' current launch window is in doubt and shuttle officials
have pledged to address the problem before the next orbiter lifts off, NASA
officials said.
"We're
going to try as hard as we can to get back in space this year because we have a
big construction project we're working on, and we need the shuttle to do it,"
Griffin said, referring to the need to complete the ISS before the shuttles are
retired in 2010. "We're not going to go until we're ready to go."
Despite the
apparent success of Discovery and the STS-114 crew, more return to flight work
is slated for the STS-121 astronauts before NASA can resume major construction
of the ISS.
"It's more
like a relay race and the torch is now passed to Atlantis and the STS-121
crew," Readdy said. "Now we have some data to work with, and for the first time
in the shuttle era, we've got a very solid place to start."
An initial
report on NASA's STS-114 foam debris investigation is expected to be presented
to ISS program manager William Gerstenmaier--tapped by Griffin to oversee the
study--later Tuesday, NASA officials said.
Smooth
landing
Despite two
weather wave-offs from KSC landings, Discovery's return to Earth went
relatively smoothly, flight controllers said. Discovery's clean bill of health--gained
through orbital
photography and in-flight heat shield
inspections--and a favorable weather outlook at Edwards made the decision
relatively simple, they added.
"It was
pretty straightforward," said LeRoy Cain, ascent/entry flight director for
STS-114, of the decision. "It was a great landing and I'm sure Eileen [Collins]
will be happy with it."
Cain said
there were some technical anomalies, such as an instrumentation glitch with
part of an orbiter auxiliary power unit system, burnt out landing strip lights
and a ground-based microwave beam, but they were only minor hitches and all had
redundancies.
During the
shuttle's descent, Collins handed the controls over to STS-114 pilot James
Kelly for about 20 seconds to give him experience at the helm, he added.
After
Discovery rolled to a stop and the hatch opened, Collins and her crew walked
around their spacecraft for a brief inspection before speaking with reporters.
"We brought
Discovery back in great shape," Collins said. "The crew was very anxious to
walk around and see what the outside looks like and it looks fantastic."
After
nearly 14 days in space - mission elapse time stopped at 13 days, 21 hours, 33
minutes and 38 seconds--Discovery's landing what as an exciting and successful
flight, she said.
"This is a
wonderful moment for all of us to experience," Collins said.
advertisement
