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.
Kennedy Space Center, Florida (CNN) -- This month will mark an end to a glorious, sometimes tragic, chapter in U.S. space history.
After 30 years of soaring into space, the shuttle program is preparing to launch into retirement.
Space Shuttle Atlantis will embark on the last flight, scheduled for Friday morning, weather permitting.
Since 1981, the fleet of space planes served the nation as a celestial service vehicle. The shuttles deployed and fixed satellites, performed scientific studies and ferried materials and people to international space station Alpha, a football field-sized construction project in orbit.
"I don't think we'll see another vehicle like it, for decades perhaps," Atlantis commander Chris Ferguson told CNN. "I mean, just the technology involved in flying back from space. It's an amazing vehicle, and its legacy will live on."
"The international space station is the crowning jewel of the shuttle program," said NASA Administrator Charles Bolden.
"It's the perfect ending for the shuttle program. We would never have been able to build the international space station without the space shuttle."
A hopeful beginning
After the Apollo space program in the 1960s -- which put a man on the moon in 1969 -- President Richard Nixon commissioned the space shuttle program in 1972. The first shuttle, Columbia, blasted off in April 1981.
Unlike Apollo, the space shuttle never ventured beyond Earth's orbit.
The shuttles, as big as DC-9 airplanes, were billed as a spacecraft that could launch and land 25 times a year.
They never did.
The shuttle proved to be an expensive, complex vehicle needing thousands of workers to get it ready for flight, and it did not have the same majesty, or sense of exploration, that was created during the Apollo era.
"Once you've been to the moon, staying home is not good enough," said Apollo astronaut Gene Cernan, who once walked on the moon.
"I'm an exploration guy. I want to go where man has never gone before. I want to see things that have never been seen with human eyes before."
The shuttle program wasn't without its critics, who took issue with the program's focus on scientific studies rather than exploration.
"I think, at times, and I hate to use the cliche, but it's sometimes has been the Rodney Dangerfield of the space program over the years," said Atlantis pilot Doug Hurley.
"But, the amount of payload it can take to orbit, and the amount of payload that it can bring back. Seven people on top of that. Where else have we seen that in the space program?
"And, my guess is we won't see that again anytime soon with a future vehicle," he added.
The program also had its tragedies: 14 astronauts died in the Challenger and Columbia accidents, in 1986 and 2003.
"We should never take it for granted," said Stephanie Stilson, NASA's flow director for the Space Shuttle Discovery.
"In order to pay tribute to the crews that we lost, and to the vehicles that we lost, we really need to keep using those experiences to remind ourselves not to take anything for granted in anything that we do," she said.
Lack of funding, political support
Today, as the federal budget tightens, NASA says there isn't enough money to continue flying shuttles.
"It has to be realized NASA has a funding problem," says Norm Augustine, chairman of President Barack Obama's panel on human space flight.
"There's just not enough money in NASA to continue the existing program and start a new program at the same time."
So, the three remaining space shuttles will be sent to museums, while the United States pays Russia $63 million per astronaut to hitch a ride to the space station.
NASA is banking on the rise of commercial space companies to build rockets and space capsules to take cargo and astronauts to the space station.
Critics say the United States is ceding space leadership and denying itself access to the very same space station that was primarily paid for by the United States.
"This is the first time in a half a century we're gonna be sitting on our hands and watching the other guys, and not being able to get into space," says Apollo 17 commander Cernan.
"Keeping a shuttle in the garage, warm and fueled and ready to go would not only be an advantageous thing but be a tremendous signal to the rest of the world that we're still in the ball game."
Space exploration must be made a national priority to secure the funding for big, lofty and risky deep space ventures, the NASA administrator says.
"The problem is that we, NASA, we the public, Congress, the nation was not very disciplined in developing the replacement for shuttle, so that we wouldn't find ourselves where we are right now," said Bolden.
Getting back into space
As the shuttle program ends, NASA still has plans to return to space exploration.
A new spacecraft, known as the Multi-Purpose Crew Vehicle, or MPCV, is a return to yesteryear, with its space capsule design.
NASA says it will carry four astronauts but not until at least 2016.
"We hope to have test flights in this decade," says Douglas Cooke, NASA's associate administrator for Exploration Systems Mission.
"It will be a mission beyond low Earth orbit."
The MPCV, built by Lockheed Martin, will be similar to the Apollo spacecraft that went to the moon and splashed down in the Pacific Ocean.
NASA says it will be 10 times safer to launch and land than the shuttle.
"We would have an abort system, all the way from sitting on the pad, to flying up, up and away," Cooke said. "The space shuttle has never had that capability."
NASA has also set its sights on returning to the moon, a trip to Mars or even a trek to an asteroid. Some of that early planning is taking place in the Florida Keys, where techniques on how to rendezvous with the asteroid are being tested.
"That asteroid can be moving. It can be spinning, and it could be spinning quite rapidly," said Bill Todd, project manager for NASA's Extreme Environment Mission Operations, or NEEMO.
"You have to get down to the surface, but once you get down to the surface ... it may just be dust," he said.
Another part of this project is taking place in Houston, where former astronaut Mike Gernhardt is developing a rover-type vehicle that can travel into deep space with a one-size-fits-all mentality.
"Rather than designing some solution for one destination ... this approach can be used on the moon, it can be used on Mars, it can be used on an asteroid, or a moon of Mars," he told CNN.
"All of that is going to save us money in the long run because we get to use it for multiple destinations," he said.
NASA's future is uncertain, but officials say they aren't worrying about it until Atlantis comes home.
"There are going to be tears of joy that Atlantis had landed," Bolden said.
"We will have done what I wanted to do ... safely flown out the shuttle."