The co-star of CBS's sitcom "Two and a Half Men" hosted the induction of three men and a woman into the U.S. Astronaut Hall of Fame Saturday at NASA's Kennedy Space Center Visitor Complex in Florida.

Emmy award-winning actor Jon Cryer served as emcee for the induction ceremony that reunited more than 20 Hall of Fame astronauts to honor 2010 inductees Guy Bluford, Ken Bowersox, Frank Culbertson and Kathy Thornton.

"So why is TV's Jon Cryer here?" the acclaimed actor and director posed to the audience. "I'm actually here because I am a 'space geek' and I think I represent space geeks everywhere. I have been one all my life and to be standing here at the Kennedy Space Center is just a fanboy dream come true."

By comparison, there was no question as to why Bluford, Bowersox, Culbertson and Thornton were selected to be the ninth class of space shuttle astronauts to be inducted into the Hall. The first African-American in space, the two space station commanders-turned-commercial spaceflight leaders and the record-setting spacewalker were a natural fit among the Hall of Fame's 73 other astronauts, 22 of whom attended the ceremony.

"One of the things that is striking to me is that in addition to the professional prowess, they are probably four of the most spectacular, just down-right good human beings that I had the opportunity to get to know during my time in the astronaut office," said 1996 enshrinee and current NASA Administrator Charlie Bolden about the 2010 class.

Dreams and plans

"I decided to chase the dream," said Bluford of his path to becoming an aerospace engineer and then an astronaut in his remarks following his induction by fellow STS-39 crew member and Johnson Space Center director Mike Coats.

"When I go out and talk to kids all the time, I tell them to work hard, aim high and chase their dreams. That's what I did," said Bluford, who flew on the first shuttle mission to launch and land at night as well as the first Spacelab flight directed by the German space agency and a Department of Defense classified mission.

"Unlike Guy I really haven't had a life plan," said Thornton, who was inducted by Dan Brandenstein, the commander of her second flight, the maiden mission of space shuttle Endeavour. "My career has been somewhat of a random walk and I owe a lot of what I have done to opportunities that came along and people who made those opportunities possible."

Thornton's "walks" included three excursions outside the shuttle, including two spent repairing the Hubble Space Telescope. Until 2007, she held the world record for the longest spacewalk performed by a female astronaut.

Thornton thanked Brandenstein for giving her the chance to do to her first spacewalk on STS-49.

"That would have been an easier decision to give to someone who was less vertically-challenged than I, but he took a chance on me and I'll forever be grateful for that."

Though Culbertson joked that he was still surprised about having been selected an astronaut, let alone being a Hall of Fame astronaut, he said flying was always the plan.

"Unlike Kathy, I did have a plan. I had planned since I was 11 to be a Navy pilot, and since I was 12 to be a test pilot and since I was 13 to be an astronaut. That was a long wait between the time I actually got selected and a lot of potential side tracks and side trips, but I always wanted to do that," Culbertson said following his induction by Bolden.

"This is a tremendous honor for me. It is a real privilege to be a member of this club. I always felt privileged to serve the country and to be a member of both the military and the astronaut corps, but most of all to be a member of the NASA team," said Culbertson, a veteran of three space missions including the third expedition to the International Space Station, when he served as commander.

"There is nothing more important than moving the frontiers further and further out and this is the community that does it. This is the one that takes the risks, whether you fly in space, you make the decisions to fly in space or you put the wrench to the bolt and tighten it to the right amount," he said.

"It takes a lot of courage to do that and allow somebody, or help somebody, get into that seat and ride that rocket," said Culbertson.

Culbertson today manages human spaceflight projects for Orbital Sciences, one of two companies with contracts to build commercial cargo spacecraft for NASA. Culbertson's counterpart at the other company, Bowersox, saw the first test flight of SpaceX's rocket successfully reach orbit just the day before his induction.

"This is a great day for me," remarked Bowersox following his enshrinement by Dick Covey, the commander of his second shuttle flight. "Yesterday was a great day because we got to launch a new rocket for the first time."

"And today I get this really neat medal and I get to sit up here with folks who taught me everything I know about space exploration and folks who I didn't get to work with when I was in the astronaut office but who inspired me when I was a kid. Even if I never became an astronaut, which was something I always wanted to do, they helped me get to study science and technology in school and learn things that were very important to accomplishing my dreams," said Bowersox.

Continue reading at to learn actor Jon Cryer's impressions of the inductees and the space shuttle program.

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