Atlantis' journey to the International Space Station will be NASA's 135th and final mission in the space shuttle program, which began 30 years ago. Tune in to CNN's live coverage of the launch Friday, starting at 10 a.m. ET on CNN, CNN.com/Live and the CNN mobile apps. Then check out "CNN Presents: Beyond Atlantis" Friday at 10 p.m. ET.
Houston, Texas (CNN) -- It wasn't like any other flight. The first one never is -- especially when your trip takes you away from the planet.
But the first space shuttle orbiter, Columbia, equipped with ejection seats, did exactly what it was supposed to do. It showed that this new winged spacecraft could safely launch, fly and return to Earth.
"They had trained us for just about everything you could think of," first shuttle pilot Bob Crippen said.
"We were ready for lots of emergencies, and thank goodness we didn't have any," he told CNN's John Zarrella.
Crippen, a Navy pilot, was making his first spaceflight.
The commander was space veteran John Young, and Columbia was Young's fifth trip into space. In 1972, he commanded Apollo 16 and became one of only 12 men to walk on the moon.
The shuttle flight would put the U.S. back in the manned spaceflight business after the Apollo program ended in 1975.
Crippen and Young spoke exclusively to CNN about their historic first flight, the 30-year-old Space Shuttle Program and the future of spaceflight.
Young and Crippen blasted off from Kennedy Space Center in Florida on April 12, 1981.
But it was the manned flight that almost wasn't. There had been serious debate at NASA about whether this first flight would be manned or unmanned.
"I guess they could have made it all automatic, but it would have taken a big redesign of the whole control system," Young said. "That would have been a lot of money and a lot of delay."
Then, there were issues with the shuttle's thermal protection system; the tiles that encompass the orbiter's belly kept falling off.
"It's why we had ejection seats in the first one," Young said. "If things really went south, we could jump out, and we had parachutes."
Crippen said he knew there were risks.
"But I wouldn't have gone to fly it if I didn't think I would be able to get back down," he added.
After the technological kinks were worked out, the vehicle was ready to fly in 1981.
"It was only once we got inside of a minute [to launch] that I looked at John and said, 'I think we're actually going to do it,' " Crippen said. "That's when my heart rate went up."
Young wasn't as excited.
"I was bored to tears," he said.
Crippen added, with a laugh, that his main concern was: "Don't let me screw up."
Young and Crippen piloted Columbia around Earth 37 times. Their flight -- essentially a test flight verifying that flight systems worked well -- lasted two days, six hours and 20 minutes.
"We were testing stuff out and making sure the payload bay doors worked right and checking to make sure the radiator deployed and stuff like that to make sure we'd operate OK on orbit," Young said. Then he added: "Everything worked, that was the amazing part ... especially on re-entry when we didn't get burned up."
Columbia landed in the California desert at Edwards Air Force Base.
Sixteen thermal tiles, which had been a nagging problem before the flight, were missing, and 148 were damaged. Engineers determined that the damage was caused by a pressure wave created by the solid rocket boosters at liftoff.
Both astronauts say it's hard to believe the Space Shuttle Program is more than 30 years old, and both agree it still has value.
"I think we ought to keep on going. I think we ought to keep on flying. That's a great vehicle. No sense quitting while it's still working," Young said.
Both men agree that NASA's future is cloudy. With talk of going to the moon, to Mars, or even to an asteroid, the agency's wishes are tied to the funding that Congress provides. So ending the Space Shuttle Program is the only way for NASA to pay for expensive deep-space exploration.
"I think it's a lot of money, but it would be worth every penny if you industrialize Mars and live and work on the moon and spread people out ... your kids and grandkids," Young said. "We'll be better off in the long haul. Bad things can happen on the Earth. Super volcanoes and asteroid impacts can wipe out a lot of folks. I think we ought to spread out a little bit."
But in the meantime, they believe the space shuttle should keep flying.
"The vehicle needs a lot of tender love and care, but it is capable of flying safely," Crippen said. "It's always going to be a risk, and if we become too risk averse, we'll never do what John and I want us to do, which is to go back to the moon and to Mars."