After U.S. Flyover, Discovery Lands in Florida

The space shuttle Discovery lands on Kennedy Space Center's Runway 33 Tuesday, April 20, 2010, in Cape Canaveral, Fla. (AP Photo/NASA,Bill Ingalls) ** MANDATORY CREDIT **
AP Photo/NASA,Bill Ingalls
Last Updated 9:15 a.m. ET

The space shuttle Discovery and its astronauts arrived back on Earth Tuesday, wrapping up a 15-day, 6 million-mile journey to the International Space Station, taking a rare flight path that carried them over America's heartland.

Discovery commander Alan Poindexter and pilot James Dutton guided the craft, landing on Runway 33 at Kennedy Space Center around 9:08 a.m. ET.

The sky over NASA's Florida landing strip cleared enough at daybreak to give Mission Control the confidence to bring the seven astronauts home. An hour before the scheduled 9:08 a.m. touchdown, commander Poindexter and his co-pilot fired the braking rockets and began their descent.

It was Discovery's next-to-last flight.

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Earlier, rain and worries about fog prompted the flight director to skip the morning's first landing attempt. Rain also thwarted Monday's tries.

The unusual flight path had Discovery crossing over America's interior. Weather permitting, the shuttle was expected to be visible as it streaked over Vancouver, British Columbia; Helena, Mont.; Wyoming; southwestern Nebraska; northeastern Colorado; southwestern Kansas; Oklahoma; Arkansas; Mississippi; Alabama; Georgia and finally Florida east of Gainesville.

NASA anticipated sonic booms might be heard as far north as Kansas.

Mission Control described to the astronauts the route they would be taking to Cape Canaveral as Discovery headed home on its next-to-last flight. "Sounds like a great ground track," Poindexter observed.

It would be the first time since 2007 that a space shuttle has descended over so much of the United States.

NASA typically prefers bringing a shuttle home from the southwest, up over the South Pacific, Central America and the Gulf of Mexico. That way, there's minimal flying over heavily populated areas. In 2003, space shuttle Columbia shattered over Texas during re-entry, but no one on the ground was injured by the falling wreckage.

NASA wanted to maximize the crew's work time in orbit, while minimizing fatigue. That resulted in this North American flyover, the last one expected as the space shuttle program draws to a close.

Before leaving the space station Saturday, Poindexter and his crew dropped off tons of supplies and equipment. The main delivery was a tank full of ammonia coolant, which took three spacewalks to hook up.

A nitrogen pressure valve refused to open after the tank was installed, and for a day, NASA considered sending the shuttle astronauts out on a fourth spacewalk to fix the problem. But engineers concluded it was not an emergency and that the space station crew or future shuttle fliers could deal with it.

History, meanwhile, was made with the presence of four women in space: three on the shuttle and one at the station.

Only three shuttle missions remain for NASA before the fleet is retired this fall after nearly 30 years of operation. Atlantis will carry up a small Russian lab and other equipment next month.

The same bad weather that prevented Discovery from returning home Monday also stalled Atlantis' trip to the launch pad. The three-mile move from the hangar has been rescheduled for Tuesday night. Liftoff is targeted for May 14.