Cape Canaveral, Fla ? NASA skipped the customary post-launch party Tuesday. The celebrating will have to wait until Discovery and its seven astronauts are safely home.

After all, Columbia looked as if it was home free until it shattered on its return to Earth in 2003.

“The first thing you learn as a student pilot is that the flight’s not over until the engine is shut off and the airplane’s tied down,” NASA Administrator Michael Griffin said after Discovery lifted off on the first shuttle flight since the disaster 2 1/2 years ago. “Twelve more days, plus, before we achieve that state, and that’s when we’ll know that this was a safe flight.”

With American pride and the future of space exploration itself hanging in the balance, Discovery rose from its pad at 9:39 a.m. CDT into a hazy blue sky, skirted two decks of clouds and headed out over the ocean in the most scrutinized launch in NASA history.

Two chase planes and more than 100 cameras documented the ascent from every possible angle to capture any sign of flying debris of the sort that doomed Columbia, and well after the shuttle had settled into orbit, NASA officials said that an object believed to be a 1 1/2-inch piece of thermal tile appeared to break off from the Discovery’s belly during liftoff. It hit near a particularly vulnerable spot, near the compartment that contains the nose landing gear.

The space shuttle Discovery lifts off at Kennedy Space Center in Cape Canaveral, Fla. Tuesday's launch, the 114th of the shuttle program, returned the U.S. to space nearly 2 1/2 years after the Columbia disaster.

Also, a large object – perhaps a piece of foam insulation – seemed to fly off from the giant external fuel tank but did not hit the shuttle itself, NASA flight operations manager John Shannon said.

“The big question is, what is that?” Shannon said. He said it was too early to say whether the two incidents posed any danger to the shuttle. Among other things, it is not yet known how deep the gouge in the tile is.

Shannon said the cameras have provided the space agency with more detailed images than it has ever seen before, and it not clear whether the debris is anything out of the ordinary. Also, the tiles on NASA’s shuttle fleet have sustained thousands of dings over the years.

Also, Shannon disclosed that the nose cone of the fuel tank hit a bird during the liftoff.

NASA promptly notified Discovery commander Eileen Collins of the debris and said the agency’s image-analysis experts were looking at the pictures frame by frame and would have more information this morning.

In addition, the astronauts will use a new 50-foot boom to inspect their ship today, and the crew of the international space station will photograph all sides of Discovery before Thursday’s linkup between the two.

NASA managers said they would take several days to make a full judgment of any damage to the shuttle and decide how to deal with it.

Celebrated return

Rachael Wilson, center, of Jacksonville, Fla., takes a picture with her cell phone while using binoculars to watch the launch of the space shuttle Discovery. A crowd gathered at a vantage point at Space View Park in Titusville, Fla., cheered Tuesday's launch.

During the 12-day mission, Collins and her crew will deliver supplies to the space station and test new techniques for inspecting and patching the shuttle in orbit.

The baffling fuel gauge problem that thwarted a launch attempt two weeks ago did not recur this time, and the countdown was remarkably smooth. If the sensor had acted up during the countdown, NASA had been prepared to bend its safety rules to get the shuttle flying.

Space program employees and relatives of both the Discovery and Columbia crews looked on nervously as the shuttle lifted off.

“On behalf of the many millions of people who believe so deeply in what we do, good luck, Godspeed – and have a little fun up there,” launch director Mike Leinbach told Collins and her crew just before liftoff.

At the Kennedy Space Center, about 2,500 NASA guests, including first lady Laura Bush and brother-in-law Gov. Jeb Bush, cheered, whistled and clapped as the shuttle lifted off, watching through sunglasses as it soared out over the Atlantic. The spectators included members of Congress as well as relatives of the 14 fallen Columbia and Challenger astronauts.

In this photo provided by the White House, President Bush watches the launch of the Space Shuttle Discovery on Tuesday from the Oval Office's Private Dining Room at the White House.

Across the country, Americans watched the liftoff, cheering and applauding in New York’s Times Square as the Discovery roared away from the launch pad. In the hometown of Japanese astronaut Soichi Noguchi, the pop of firecrackers and congratulatory cheers of “Banzai!” rang out.

From Washington, the president wished the crew a safe and successful mission.

“Our space program is a source of great national pride,” he said in a statement, “and this flight is an essential step toward our goal of continuing to lead the world in space science, human spaceflight and space exploration.”

Tribute to the fallen

Hours after Discovery had settled into orbit, Collins paid tribute to “the great ship Columbia and her inspiring crew” and said of the fallen astronauts: “We miss them and we are continuing their mission. God bless them tonight and God bless their families.”

Images taken from NASA TV show a bird being hit by the nose cone Tuesday during launch of shuttle Discovery at Kennedy Space Center in Cape Canaveral, Fla. The illustration was shown during an afternoon news conference.

Griffin, NASA’s chief, urged everyone “to take note of what you saw here today: the power and the majesty of the launch, of course, but also the competence and the professionalism, the sheer gall, the pluckiness, the grittiness of this team that pulled this program out of the depths of despair 2 1/2 years ago and made it fly,”

The liftoff was a relatively solemn affair. NASA did not hold a post-launch party, but the launch control team ate cornbread and beans in what has been a long post-liftoff tradition.

“There won’t be any real sighs of relief – at least from me or from the collective – probably until the crew is walking around the vehicle on the runway in Florida after the mission is over,” flight director LeRoy Cain said from Houston.

In all, nearly 50 safety improvements were made to the shuttle in the wake of Columbia tragedy. The fuel tank was extensively redesigned, with less foam insulation than before but extra heaters to prevent a dangerous buildup of ice once it is filled with super-cold liquid propellant. NASA feared falling ice could be as lethal as chunks of foam.

Also, dozens of motion and temperature sensors were embedded in the wings to detect any blows from debris.

At the same time, the space agency revamped the way it makes decisions and listens to dissenting views, especially from lower-level employees. Columbia accident investigators blamed the catastrophe in part on a broken safety culture, or a tendency to downplay risks and discourage engineers from speaking up.

While in orbit, the astronauts will try out repair kits on deliberately broken samples of thermal tiles and panels. They will practice working with goo and other patching materials and different types of brushes, putty knives and a caulking gun.

In addition to Collins and Noguchi, the crew members are pilot James Kelly; Stephen Robinson; Andrew Thomas; Wendy Lawrence; and Charles Camarda.