Shuttle Safely Returns to Cape Canaveral

CAPE CANAVERAL, Fla., July 17 — With a distinctive double sonic boom and a whooshing glide to the ground, the space shuttle Discovery landed safely today, ending a 13-day mission that paves the way for completion of the International Space Station.

“Welcome back, Discovery,” Stephen N. Frick, a NASA astronaut communicating with the shuttle from mission control in Houston, said to the shuttle commander, Col. Steven W. Lindsey, after the shuttle had come to a halt.

“This was a great mission, a really great mission,” Colonel Lindsey replied. “Enjoyed entry and landing.”

The shuttle began its descent about an hour earlier over the Indian Ocean near the coast of Sumatra, firing its jets for what is known as the de-orbit burn.

Then the shuttle, which had been circling the earth upside down with its engines facing forward, flipped to face its nose forward and its cockpit upward for landing.

As it entered the atmosphere, superheated gas known as plasma heated the outer surfaces of the craft to about 3,000 degrees Fahrenheit, and the shuttle executed a series of computer-controlled S-curves that helped it to slow to landing speed.

Those below heard a characteristic twin sonic boom generated by the nose and wings as the shuttle neared the Kennedy Space Center landing strip at supersonic speeds. As spectators stood near the landing strip, the shuttle broke through the cloud layer in the plummeting descent at an angle seven times steeper than commercial aircraft and nearly 20 times as fast.

After the landing, as he prepared to leave the shuttle, Colonel Lindsey radioed to mission controllers that “it was a fun entry — it was beautiful.” He described the colors of superheated plasma and the light of dawn, saying, “We could see the bright orange glow above, and I could see the earth moving below. It was spectacular. We could actually see the moon through the plasma.”

The astronauts emerged from the shuttle trailer at 10:45 and were greeted with handshakes and hugs by space agency senior managers, including the NASA administrator, Michael D. Griffin. Members of the crew walked under Discovery and examined it to see how the spacecraft had fared in its fiery descent.

Shortly after the inspection, the astronauts lined up in front of the vehicle for a statement from Colonel Lindsey. In his four shuttle flights, he said, “I’ve never seen a vehicle that looked as clean as this one did” upon landing. He thanked NASA’s crew on the ground and then his shuttle crew, who he said were “nearly perfect” in their performance.

“I actually had to throttle ‘em back and give them a little bit of time off,” he said. “It was a privilege for me to work with them. “

Because the shuttle comes back to earth as a glider, flying it is famously tricky. In a 2004 memorandum to shuttle workers, N. Wayne Hale, Jr., the manager of the shuttle program, wrote, “The orbiter flies like a brick, with handling qualities that would make a Mack truck proud.”

At dawn today at the Kennedy Space Center, there were thunderstorms about 40 miles to the north that threatened to scuttle landings for the day.

But just before 8, the message came from Houston that weather was not a concern, and the Discovery’s commander and pilot were given the green light to bring the 115th mission of the shuttle program back to earth.

“Discovery, Houston, good news,” Mr. Frick told Colonel Lindsey. “You’re go for the de-orbit burn.”“Roger that,” Colonel Lindsey replied. “Go for the de-orbit burn.”

The astronauts also prepared for landing by drinking between eight and 12 ounces of fluid every 15 minutes along with salt tablets, in order to increase the amount of fluid in their bodies.

The shuttle rose toward space on a column of fire and smoke on July 4, with seven astronauts aboard. The mission was to bring supplies to the half-finished space station, conduct repairs on it that would allow the resumption of construction during future shuttle flights, and carry up a new crew member, Thomas Reiter, a German astronaut from the European Space Agency. Mr. Reiter remained behind aboard the International Space Station, bringing its crew to three for the first time since the Columbia disaster.

The shuttle crew on this second return-to-flight mission was led by Colonel Lindsey, an Air Force officer making his fourth trip to space and his second as a commander. The pilot, Mark Kelly, was on his second shuttle mission, and is a commander in the Navy.

One of the two spacewalkers on the mission, Piers J. Sellers of England, flew one mission before this one, and walked in space three times; the three space walks on this mission brought his total to six.

The other members of the crew were taking their first shuttle flights. Michael E. Fossum performed the three spacewalks with Dr. Sellers. The flight engineer, Cmdr. Lisa M. Nowak of the Navy, operated the robot arm during their spacewalks. The transfer of tons of cargo between the two craft was supervised by Stephanie D. Wilson, who was born in Boston and got her undergraduate engineering degree from Harvard.

During the mission, crew members transferred thousands of pounds of supplies to the station and brought thousands of pounds of trash and discarded equipment back home with them. In the three spacewalks, Mr. Sellers and Mr. Fossum repaired a kind of rail car that is used to move equipment and which will be essential for adding modules to the space station.

They also installed new equipment outside of the station, tested technologies and techniques for repairing small areas of damage to the shuttle’s thermal protection system in orbit, and performed an experiment to see if an extension of the shuttle’s robot arm can be used as a work platform without too much sway or wobble.

Discovery is completing the second shuttle flight since the Columbia disaster three years ago. Columbia and its crew of seven were lost when returning from a mission because of damage done to the heat shield panels on its wing by debris from launching. Afterward, NASA spent more than $1 billion in an effort to reduce the debris hazard and improve inspection of shuttles in space.

NASA hopes to fly 16 more space shuttle missions, primarily for space station construction, before retiring the fleet in 2010. That will mean speeding the tempo of flights to about four each year, the program’s average before Columbia, with the next flight beginning as early as the end of next month.

But Colonel Lindsey told CBS News Sunday that returning to routine missions would not mean business as usual or neglecting the lessons of the Columbia’s loss.

“Just because we’re going to be back to flight doesn’t mean we’re going to change the way we’re operating,” he said. “We’re going to be very careful, very cautious, look at everything — and we’ll leave no stone unturned as we continue with this program.”

John M. Logsdon, the director of the space policy institute at George Washington University, said that by completing what NASA called the second test flight after the Columbia tragedy, the space agency is “back to work” to complete the international space station — but cautiously.

“This shows that with appropriate care and vigilance, the odds of operating the shuttle with acceptable risk are good,” he said.

But “It doesn’t mean the shuttle is safe,” he added. “The shuttle will remain a very risky vehicle, to be operated with extreme care.”