Astronauts may need to take the unprecedented step of temporarily abandoning the International Space Station if last week's Russian launch accident prevents new crews from flying there this fall.

Until officials figure out what went wrong with Russia's essential Soyuz rockets, there will be no way to launch any more astronauts before the current residents have to leave in mid-November.

The unsettling predicament comes just weeks after NASA's final space shuttle flight.

"We have plenty of options," NASA's space station program manager, Mike Suffredini, assured reporters Monday. "We'll focus on crew safety as we always do."

Abandoning the space station, even for a short period, would be an unpleasant last resort for the world's five space agencies that have spent decades working on the project. Astronauts have been living aboard the space station since 2000, and the goal is to keep it going until 2020.

NASA satellite data from the years 2000 through 2011 show the Earth's atmosphere is allowing far more heat to be released into space than alarmist computer models have predicted, reports a new study in the peer-reviewed science journal Remote Sensing. The study indicates far less future global warming will occur than United Nations computer models have predicted, and supports prior studies indicating increases in atmospheric carbon dioxide trap far less heat than alarmists have claimed.

Study co-author Dr. Roy Spencer, a principal research scientist at the University of Alabama in Huntsville and U.S. Science Team Leader for the Advanced Microwave Scanning Radiometer flying on NASA's Aqua satellite, reports that real-world data from NASA's Terra satellite contradict multiple assumptions fed into alarmist computer models.

Now that space shuttle Atlantis has returned home safely, America's human spaceflight program faces a period of retrenchment and doubt.

Atlantis' landing early Thursday morning marked the end of NASA's 30-year space shuttle program and the beginning of layoffs for the space agency. On Friday, 1,500 shuttle workers are scheduled to get their pink slips. By the time all the layoff notices are handed out, a total of 8,000 workers will have been cut.

At its peak, the shuttle program had about 11,000 people working for it.

NASA's space program, however, is hardly over. Astronauts will continue to live for months at a time on the International Space Station until at least 2020. Eventually, the Obama administration proposes they go explore a passing asteroid and ultimately land on Mars.

Atlantis made the perfect landing as dawn broke this morning, gliding down on to the tarmac at Kennedy Space Center, Cape Canaveral, to bring to an end 30 years of shuttle missions.

It the 135th mission for the fleet, which has covered an astonishing 542million miles and circled Earth 21,150 times.

And considering this accomplishment, none of the record 2,000 gathered by the landing strip to witness the historic spectacle was complaining that Atlantis was precisely one minute late.

The five shuttles have carried 355 people from 16 countries - and here were the last four astronauts safely home to cheers and tears.

As Commander Christopher Ferguson eased Atlantis on to the runway, he radioed: 'Mission complete, Houston'.

'Job well done, America,' replied Mission Control.

A space shuttle has pulled up for the last time at a space station.

Emotions were running high Sunday, in orbit and on Earth, as Atlantis arrived at the International Space Station.

It's the final docking to a space station ever by a NASA shuttle. Atlantis is being retired after this flight, the last of the 30-year shuttle program.

Mission Control's lead flight director declared "this is it" as he gave the OK for the historic linkup.

Atlantis is delivering four tons of food, clothes and other space station provisions. That represents a year's worth of supplies, providing a safety net for station crews in the looming post-shuttle era.

The 10 orbiting astronauts will spend the next week unloading everything.

Atlantis has blasted off on NASA's last space shuttle launch.

The historic liftoff occurred Friday morning, 30 years and three months after the very first shuttle flight.

Four astronauts are riding Atlantis to orbit. The shuttle is bound for the International Space Station, making one final supply run.

Hundreds of thousands of spectators jammed Cape Canaveral and surrounding towns for the farewell. Kennedy Space Center itself was packed with shuttle workers, astronauts and 45,000 invited guests, the maximum allowed.

The flight will last 12 days. Weather permitting, Atlantis will return to Kennedy, where it will end up on permanent display.

NASA fueled space shuttle Atlantis on Wednesday, but it was only a test leading up to the last flight of the 30-year program.

Liftoff isn't until July 8. Shuttle managers want to make sure that repairs to the external fuel tank are good and that no cracks pop up in any of the support brackets.

That very problem kept shuttle Discovery grounded late last year. The same kind of patches—applied to the aluminum struts in the center portion of the tank—were used for Atlantis.

The struts, or brackets, are located in an area where there is no fuel, only instruments. The brackets were made from an aluminum alloy that was more brittle and that, combined with assembly issues, led to the cracking on Discovery's tank. Technicians will X-ray the brackets on Atlantis' tank beginning this weekend.

Space shuttle Endeavour and its six astronauts returned to Earth early Wednesday, closing out the next-to-last mission in NASA's 30-year program with a safe middle-of-the-night landing.

Endeavour glided down onto the runway one final time under the cover of darkness, just as Atlantis, the last shuttle bound for space, arrived at the launch pad for the grand finale in five weeks.

Commander Mark Kelly - whose wife, wounded Rep. Gabrielle Giffords, remained behind at her rehab center in Houston - brought Endeavour to a stop before hundreds of onlookers that included the four Atlantis astronauts who will take flight in July. He waited hours before calling her, so he wouldn't wake her up.

NASA does all kinds of stuff. They build space robots. They send up satellites. They study the oceans.

But come on - who're we kidding? When most people think of NASA, they think of manned space flight. The space shuttle.

But after 30 years, and 135 flights, NASA has decided to close down the space shuttle program.

The Shuttle is an amazing machine. It takes off like a rocket, but lands like a plane, so it's re-usable. It's had some spectacular successes. It carried the Hubble Space Telescope into orbit, letting us see millions of times farther into space than we ever could before.

And the shuttle built the International Space Station, hunk by hunk, made possible by its huge cargo bay, its airlock, and its robotic arm.

It launched the first American female astronaut into space, and the first black astronauts.