NASA astronaut Rex Walheim signs an autograph at the welcome home ceremony for the astronauts of the final shuttle mission Friday, July 22, 2011, in Houston. (AP Photo/Pat Sullivan)

(AP) -- It may have been the final big official event of the last space shuttle mission, but a welcome-home and thank-you party for the crew of Atlantis Friday wasn't dwelling on any sad ending.

Despite pending layoffs and triple-digit temperatures, it was a hopeful attitude that filled an airplane hangar with no air conditioning for the traditional welcome home for the shuttle crew. What wasn't traditional was the size of the crowd - in the thousands - and that this was the last shuttle crew, a team that calls themselves The Final Four. But no one talked of an end of exploring space, rather that it was the start of something new.

"This is living proof that the dream is still alive and will remain alive in this little period of lay off," Atlantis Commander Christopher Ferguson told a cheering, flag-waving crowd of thousands.

Speaking in front of a 15-foot tall American flag, Atlantis astronaut Rex Walheim agreed.

"This is a celebration," Walheim said, telling people not to concentrate on the end of space shuttle flights "but smile because it happened. We're going to have another program coming down the line that we're going to be just as proud of."

Eleven-year-old Brandon Pitts is counting on it.

"I always wanted to be an astronaut," he said, while straining against a rope line. He clutched an Atlantis jigsaw puzzle, trying to get a good view.

Some people may have lost interest in space, but once NASA starts and stays focused on its next big mission, that attention will return, Ferguson said.

"If we build it, they will come," Ferguson said.

The decision to cease was made seven years ago, barely a year after the Columbia tragedy. President nixed President George W. Bush's lunar goals, however, opting instead for astronaut expeditions to an asteroid and Mars.

Last-ditch appeals to keep shuttles flying by such NASA legends as Apollo 11's and Mission Control founder Christopher Kraft landed flat. NASA is retiring the shuttles, according to the program manager, so it can get out of low-Earth orbit and get to points beyond. The first stop under Obama's plan is an asteroid by 2025; next comes Mars in the mid-2030s.

They came by the thousands to Houston's Ellington Field to see the crew, get autographs and space memorabilia. The crowd mobbed the crew - including pilot Douglas Hurley and Sandra Magnus - who were tired from their 13-day flight to resupply the International Space Station, so officials had to ask them to step back a bit in the push for autographs.

Justin Tesno, 10, came out of the throng with Ferguson's autograph on his hand-held fan, saying "It was worth it."

The event was also a pep rally for the city of Houston, which houses Mission Control at Johnson Space Center. Ferguson said "Houston has taken it on the chin a little bit," and unveiled a thank you poster that flew on that final mission.

The poster said: "Houston. Always the first word in space. Thank you!"

But this wasn't just a Houston thank you.

Teresa Santana and her family were on vacation from Mexico, and decided they had to come to the Atlantis welcome-home party. She didn't think this was near the end of Americans in .

"It's historic," Santana said, adding: "They're going to keep working on more."

More information: NASA's Johnson Space Center: http://www.nasa.gov/centers/johnson/home/index.html