KENNEDY SPACE CENTER, Fla., Aug. 21 — The space shuttle Endeavour glided to a safe landing here Tuesday afternoon, apparently not much worse for wear.

A look at the underside of the Endeavour appeared to validate the decision by mission managers not to try to repair a small but deep gouge, caused by a falling piece of foam, in two heat tiles on the underside of the right wing. The ultrahot gases streaming past the wing surface on re-entry burned a slightly larger scoop out of the gouged tiles, but the additional damage to the craft appeared to be limited.

At a news conference with the astronauts after the landing, Cmdr. Scott J. Kelly of the Navy, the Endeavour’s commander, said the damage the gouge could have cause on re-entry “crossed my mind for a moment, because I knew I was going to be asked about it.”

But really, Commander Kelly said, “I didn’t worry about it at all.”

And when he finally saw the damage after landing, he said, “I was a little underwhelmed by the size of the gouge.”

Michael D. Griffin, NASA’s administrator, who greeted the returning astronauts on the runway and also examined the damage close-up, said he saw some signs of heating and some erosion. “But over all, you’d be hard put to tell it went through a re-entry,” Dr. Griffin said at the news conference.

Tiles in that area will be removed for examination of the underlying aluminum structure.

The Endeavour returned “in outstanding condition” over all, said Michael D. Leinbach, the shuttle launching director at the Kennedy Space Center. “Very few dings otherwise.”

Also returning to Earth was Barbara R. Morgan, the former teacher who was the backup to Christa McAuliffe to be NASA’s first teacher-in-space. After the Challenger broke up on launching in 1986, killing Ms. McAuliffe and the other six astronauts aboard, Ms. Morgan returned to teaching before changing careers to become a full-time astronaut.

At the news conference five hours after landing, Ms. Morgan, wearing her blue astronaut uniform and a red baseball cap, walked woozily to her seat. Asked about her future plans, she answered, “My first plan is to get rid of the room spinning.”

Ms. Morgan, who in her educator role during the mission held video chats with schoolchildren, said she would look for opportunities to use her experience in space to inspire students. She also said she would not take back comments she made before the mission that teaching was more challenging than being an astronaut.

The landing concluded a successful mission that lasted 12 days, 17 hours and 55 minutes and covered nearly 5.3 million miles in 201 orbits. During the visit to the International Space Station, Endeavour astronauts conducted four spacewalks to perform construction on the space station, which is now about 60 percent complete.

While the falling foam had, in the end, little effect on the Endeavour, it may have repercussions for later flights. Engineers are analyzing whether modifications should be made to brackets that hold a fuel line on the external fuel tank. Ice that formed on the brackets after the tank was filled with ultracold liquid hydrogen and oxygen is believed to have caused a small piece of foam, about one-third of an ounce, to come loose 58 seconds into flight.

NASA has delayed attaching the solid rocket boosters to the external fuel tank for its next mission, with the shuttle Discovery, until a decision is made on what to do with the brackets. Mr. Leinbach said that there was a cushion of several days in the schedule of preparations for the launching of the Discovery, and that modifications like reducing the amount of foam on the brackets would take at most a couple of days.

“We’re still pointed to Oct. 23 for our launch,” Mr. Leinbach said.

Perhaps more likely to be affected is the subsequent mission, the launching of the Atlantis in early December, because the final preparations of attaching the orbiter to the external fuel tank cannot take place in NASA’s giant Vehicle Assembly Building until the Discovery is moved out of the building to the launching pad.

Dr. Griffin said he and William H. Gerstenmaier, the associate administrator for space operations, were inclined not to make changes, because the foam on the brackets was small and it was unclear whether changes would improve or worsen the situation.

NASA is also looking at possible changes to its countdown schedule. Following the loss of the Columbia in 2003 because of damage caused by falling foam, a one-hour “hold” was added to the countdown to allow inspectors to look for ice buildup. But the extra time may also allow more ice to form.

The primary mission on Tuesday was the Endeavour’s safe return. At 11:05 a.m. Eastern time, Christopher J. Ferguson, an astronaut at the mission control center in Houston, radioed to the Endeavour crew, “You are go for the de-orbit burn.”

At 11:25, over the Indian Ocean, the Endeavour fired its maneuvering thrusters for 3 minutes and 35 seconds. For the next hour, it dropped out of orbit toward Earth’s atmosphere. The craft cruised over Costa Rica and Cuba, then over southern Florida, where the skies were blue with broken clouds and a steady breeze.

Two quick, loud sonic booms thundered across the space center as the shuttle passed to the east. It then made a U-turn for its final approach from the north. In a picture-perfect landing, its rear tires touched the runway at 12:32 p.m., and the nose gently swiveled to the ground 13 seconds later. Slowed by a drag chute, it rolled to a stop about a minute later.

“Congratulations, welcome home,” Mr. Ferguson said to the Endeavour crew. “You’ve given a new meaning to ‘higher’ education.”