Despite lingering concerns about insulating foam falling from the shuttle's external fuel tank, NASA set off the biggest fireworks display of all Tuesday, successfully launching Discovery and its seven astronauts on a mission to the International Space Station.
"I can't think of a better place to be on the Fourth of July," shuttle Cmdr. Steven Lindsey said minutes before launch. "We hope to give you an up close and personal look at the rocket's red glare."
Discovery blasted off at 11:38 a.m. PDT, propelled into space on a bright cone of fire that competed with the summer sun.
The shuttle's 149-foot-long solid rocket boosters and its three main engines drove the 4.5-million-pound craft into orbit in a little more than eight minutes.
The mission is the second and final test flight of the shuttle as the space agency recovers from the Columbia disaster in 2003. A falling piece of foam was blamed for damaging the craft, which broke up on reentry, killing all seven of its crew members.
After an initial look at images taken during the launch, shuttle program manager N. Wayne Hale Jr. said that the fuel tank "performed very well indeed."
"Nothing gives us any concern about the health of the vehicle," he said.
Although he emphasized that the imagery team would not be able to clear Discovery for reentry into the atmosphere until completing a fuller analysis of its heat shield, Hale said very little foam came off the tank.
He said there were five events in which debris came off the tank beginning 173 seconds after launch, when five small pieces of foam flaked off.
The tank continued to lose foam for the next three minutes, including one piece at nearly five minutes into the launch that appeared to have hit the underside of the craft.
Space shuttle managers said the pieces did not pose a threat to Discovery. The first incident occurred when the shuttle was 240,00 feet above Earth, where the air is so thin it would not be capable of accelerating debris to a damaging speed.
The crew also reported seeing something about 6 to 8 feet long drift away from Discovery. They thought it might be a thermal blanket used on the side of the craft. The material has come off in the past, but that amount would be highly unusual.
Hale confirmed late Tuesday that the debris was actually ice that sloughed off Discovery's main engines as it reached the freezing upper atmosphere. Video images showed the 8-foot-long string of ice falling off.
Hale said the evidence, so far, did not point to trouble. "What we've seen so far is very encouraging," he said.
He said it would be at least three days before the analysis of all the data and camera images was complete, at which time NASA would be able to determine whether there was any danger in bringing Discovery home after its 12-day mission.
The feeling among NASA management was celebratory after the launch.
"We had a great day," said John Shannon, chairman of the shuttle mission management team, which gave the go-ahead for launch Tuesday, after several days of bad weather, along with several technical problems that threatened the mission.
Discovery is carrying 2 tons of provisions for the space station and an equally heavy load of expectations and anxieties.
The hopes were that with a problem-free flight, the wounded American space program could get back on the fast track of space exploration.
"Now is the time to pick up the normal ... tempo and get about our business," said NASA Administrator Michael D. Griffin.
That business includes completing construction of the International Space Station, which remains half-built and in limbo since the Columbia accident. Plans call for 16 more shuttle missions before the fleet is mothballed.
Still, there are persistent worries about the shuttle's foam problems. The external fuel tank has been extensively modified over the last year -- the most since the shuttle began flying in 1981.
Last year's first post-Columbia shuttle flight was troubled from the start, when a 1-pound piece of foam flaked off during launch. Griffin grounded the fleet and ordered a redesign of the fuel tank, which led to the removal of more than 30 pounds of foam.
But the problems have not been completely solved.
This mission had been on the drawing board for months but became controversial when Griffin overruled two of his top safety officers in approving a launch.
The dissenters believed the space agency should redesign a portion of the fuel tank called the ice frost ramps before attempting another launch. The fear was that foam could come off those ramps and damage the craft.
In fact, some of the debris spotted Tuesday during the launch appeared to come from the area of the ice frost ramps, which protect brackets alongside the fuel tank's main liquid oxygen feed-line.
Griffin approved the launch anyway, reasoning that no foam large enough to be harmful had ever come off the ice frost ramps. He also said he wanted to see how the other design changes worked out before embarking on more modifications.
Asked whether he felt vindicated after Discovery's launch Tuesday, Griffin said no.
"The decision we made was obvious on the numbers," said Griffin, an engineer who takes pride in his unemotional, pragmatic approach to his job. "We keep coming back to feelings. I'll have time for feelings after I'm dead."
Discovery's cargo hold carries food and water, along with a back-up oxygen generator that will allow the space station to eventually support a crew of six.
A Discovery crew member, European Space Agency astronaut Thomas Reiter, will remain at the station, the first time it will have a three-person crew since before the Columbia accident.
The first day of Discovery's mission was devoted to reaching a good orbit from which to approach the space station. The crew also deployed a communications antenna and took pictures of the orbiter to find potential damage. The shuttle is scheduled to dock with the space station on Thursday.
If no serious problems crop up during Discovery's mission, NASA may try to launch the shuttle Atlantis in August and possibly a third in December.
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The primary goals of Discovery's 12-day mission are to test safety improvement to the shuttle and ferry more than 28,000 pounds of supplies and equipment to the International Space Station.
Shuttle commander, 45, is an Air Force colonel and a veteran of three previous shuttle flights. He was also the mission commander of shuttle mission STS-104 in 2001. He served as pilot on his two other missions in 1997 and 1998. He was born in Arcadia.
Shuttle pilot, 41, is a Navy commander. He is a 10-year veteran of the astronaut corps and has been on one previous shuttle mission. He served as the pilot on STS-108 in 2001.
Mission specialist, 47, is an astronaut from the European Space Agency. He spent 179 days aboard the Mir space station in 1995. He will stay aboard the International Space Station for several months.
Mission specialist, 39, is an engineer who formerly worked at the Jet Propulsion Laboratory in La Canada Flintridge. She has been an astronaut for 10 years. This is her first spaceflight.
Mission specialist, 48, is a colonel in the Air Force Reserve. Before becoming an astronaut, he was a systems engineer for NASA. This is his first spaceflight.
Mission specialist, 50, is a scientist whose specialty is studying climate systems. He has been an astronaut for 10 years and has been on one previous shuttle mission, STS-112 in 2002.
Mission specialist, 42, is a Navy commander and has been an astronaut for 10 years. This is her first spaceflight.