Space shuttle Discovery, crew of 7 back on Earth

[April 21, 2010]  CAPE CANAVERAL, Fla. (AP) -- Shuttle Discovery and its astronauts returned safely to Earth on Tuesday after making a rare flyover of America's heartland to wrap up their 15-day, 6 million-mile journey to the International Space Station.

The touchdown was delayed by rain and fog that dissipated as the sun rose, allowing Mission Control to take advantage of the morning's second landing opportunity.

Shuttle commander Alan Poindexter held a small U.S. flag as he stood in front of Discovery, two hours later, and described the "beautiful entry."

"We got the bonus of coming over the entire United States, and it was just absolutely gorgeous," said Poindexter, flanked by his six crewmates. "The entire entry track took us over the Rockies and over the Midwest and across the Mississippi Delta. It was just a fantastic entry."

Discovery swooped through a hazy sky before landing a day late because of rain. Within a few hours of completing what one NASA manager described as an "unbelievably successful mission," the space agency was announcing delays to its last two shuttle flights.

NASA almost certainly will need to keep the shuttles flying beyond the advertised September retirement date, said Mike Moses, a launch manager. He stressed the intention still is to wrap everything up by year's end. A final launch schedule is expected in the next few weeks.

No matter what, this was Discovery's next-to-last flight. Only one more mission remains for NASA's oldest surviving shuttle. Once removed from the runway, it was going to start undergoing preparations for a fall launch.

Until this week, Discovery was scheduled to make the last shuttle flight in September. But following touchdown, NASA reported a major delay for its next-to-last mission, a space station trip by Endeavour to deliver a particle physics detector. Science teams in Europe want to replace the magnet in the Alpha Magnetic Spectrometer so it can operate longer in orbit. Doing so means the instrument will not be ready for a late July liftoff, as initially planned.

Moses said all options are being explored, including swapping the order of the last two flights or changing which shuttle flies what.

For days, NASA had promised a spectacular show, weather permitting, for early risers along Discovery's flight path. The 1 1/2-hour delay Tuesday morning may have made it more difficult to spot the descending shuttle, Moses said.

Discovery zoomed over the North Pacific on its way home before crossing into North America over Vancouver, British Columbia. Then it headed toward the southeast, flying over northeastern Washington, Helena, Mont.; Wyoming; southwestern Nebraska; northeastern Colorado; southwestern Kansas; Oklahoma; Arkansas; Mississippi; Alabama; Georgia and finally Florida east of Gainesville.

A NASA research team captured infrared images of the shuttle zooming over Arkansas. In addition, NASA received reports of sonic booms being heard as far away as Tuskaloosa, Ala.

It was the first time since 2007 that a space shuttle descended over so much of the United States. With the shuttle program winding down, there aren't expected to be any more continental flyovers.

NASA typically prefers bringing a shuttle back 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 crossing.

Mission Control radioed congratulations as soon as Discovery touched down on the runway.

"It was a great mission. We enjoyed it," Poindexter said. "And we're glad that the International Space Station is stocked up again."

Before leaving the space station Saturday, Poindexter, a Navy captain, and his crew dropped off tons of supplies and equipment. Poindexter is the son of retired Navy Adm. John Poindexter, national security adviser under President Ronald Reagan.

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.

Discovery returned with a couple tons of trash and discarded space station equipment. Most of that was jammed into a cargo carrier that was launched April 5 with three times that in fresh supply weight. The Italian-built carrier will be outfitted, reflown and installed permanently at the orbiting outpost sometime this fall.

Only three shuttle missions remain for NASA before the fleet is retired 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 to Kennedy Space Center on 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.

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On the Net:

NASA:
http://www.nasa.gov/mission_pages/
shuttle/main/index.html

NASA:
http://spaceflight1.nasa.gov/realdata/sightings/

[Associated Press; By MARCIA DUNN]

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