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.
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.
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