KENNEDY SPACE CENTER, Fla. - With the thunderous roar of 7.5 million pounds of thrust, equivalent to the power of a small nuclear device, America re-launched its era of space flight yesterday, sending seven astronauts into orbit aboard the space shuttle Discovery.

The exuberance surrounding the launch was tempered, however, when NASA engineers discovered three events that occurred during the 8.5-minute ride into space that raised concerns about the shuttle's heat shields, the critical system that was at fault in the Columbia accident 30 months ago.

NASA officials said they would begin a detailed analysis of launch photography and a thorough in-orbit inspection of the craft using its robotic arm.

NASA cameras and radar found that a 1.5-inch section of heat-resistant tile sheared off from the nose landing-gear door, damage they could not fully assess without more detailed inspection, said John Shannon, flight operations and integration manager.

The cameras also detected an object floating away from the shuttle just after the solid rocket boosters had separated two minutes after launch. And the shuttle's external tank hit a bird seconds after launch, he said.

So far, the experts cannot say whether the events jeopardize safety, Shannon said.

"It's way premature to say there is a serious problem," said Shannon. But he added, "I'm not going to sit in here and sugar-coat anything."

Tens of thousands packed highways near the launch site and millions watched on television as Discovery's engines painted the morning sky a brilliant gold and shook Florida's eastern coastline at 10:39 a.m. The spacecraft quickly disappeared into low clouds.

NASA managers, emerging from one of the darkest periods in the four-decade history of the space program after the loss of Columbia, heaved sighs and slapped each other on the back in celebration.

"Take note of what you saw here today," NASA Administrator Michael D. Griffin said in a news conference shortly after the launch. "The power and majesty of the launch, but also the competence and professionalism, the sheer gall and pluckiness of this team that pulled this program out of the depths of despair 2 1/2 years ago and made it fly."

NASA had been sorely tested in the wake of the Feb. 1, 2003, Columbia tragedy, with outside critics and even many individuals within the agency openly questioning whether America's vaunted space jockeys had lost the can-do engineering skills that put men on the moon in less than a decade and won the space race against the former Soviet Union.

The answer to that question could be read in the faces of top managers gathered at the 140,000-acre launch site under thickly humid, sunny skies.

"It's a great day, with America back in flight in an American vehicle," said Wayne Hale, the deputy shuttle program manager.

First lady Laura Bush, watching from a grandstand filled with 2,500 close-up observers, said it was "pretty terrific" that the first flight after Columbia was commanded by a woman, Eileen Collins.

During the 13-day mission, the seven-member crew plans to dock with the International Space Station, replace a failed gyroscope and perform three space walks, one of which will test shuttle repair techniques developed after Columbia.

It will take three days for the shuttle to maneuver to the higher-flying station.

After another test mission with the shuttle in September, NASA hopes to resume assembly of the space station, a job that was put on hold after the Columbia accident. In the past two years, plans for the station have been scaled back and now NASA hopes to end its involvement in the program not long after the agency finishes building it.

The shuttle took 8.5 minutes to reach orbit. After the main engines shut off, Collins took the control stick and flipped the orbiter over so the crew could photograph the external tank as it drifted away.

The photos will be downloaded to NASA engineers, who will analyze whether any foam insulation fell off the tank and potentially damaged the orbiter.

Shannon said the tile damage occurred in a sensitive area near a seal on the nose landing-gear door. A laser inspection tool will be used today to determine the depth of the gouge, which is critical to determining whether it is a safety hazard.

The object floating away from the shuttle after solid rocket booster separation is of concern because, so far, NASA has not been able to estimate its size, whether it caused any damage or even where it came from.

NASA managers said they would begin scanning images of the launch last night. It will take up to six days to analyze all the evidence.

The Los Angeles Times is a Tribune Publishing newspaper.