The final liftoff of the Atlantis on July 8 marked the closing chapter of America's space shuttle era. The 30-year program delivered some stunning scientific successes, but also some major disappointments, and the general sentiment among those looking back over the shuttle's history is bittersweet.

"I feel an overall sense of relief that [Atlantis's] launch went well and that the shuttle program is over," space policy and history expert John M. Logsdon told CBC News.

The Professor Emeritus of Political Science and International Affairs at George Washington University in Washington, D.C., believes the shuttle program should have ended years ago and been replaced with more modern spacecraft technology, but says it had to be extended so the International Space Station could be completed.

"The original plans were to fly each orbiter 100 times over a 10 year period," he said, "but it cost 20 times more than anticipated and never came close to fulfilling NASA's goals as far as cost or frequency."

Others were more emotional upon seeing the final launch.

"I got a bit choked up realizing it is the end of an era," University of British Columbia astronomy and astrophysics professor Jaymie Matthews said. "I was at the very first shuttle launch, so this is like a bookend in my life."

But Matthews agrees the shuttle program fell short of its original, lofty goals in many respects.

"You'd have to do a lot of searching to find a scientist who is a big booster of the shuttle program," he said.

According to Matthews, one of the contentious issues surrounding NASA's space program for the past several decades was that instead of using a more varied mix of manned and unmanned spacecraft, the Americans decided early on to make the shuttle their all-purpose "space truck."

One of the consequences was that while the shuttle had a relatively low accident rate for a space vehicle, every launch involved a crew. "People lost sight of the fact that [the Shuttle] was essentially setting off a giant roman candle with people in it," he said.

The loss of 14 lives and two shuttles over the course of the three-decade program meant the Challenger and Columbia disasters of 1986 and 2003 gave the world "a front-row seat" to the perils of space flight, Matthews said. That ultimately had an impact on the public image of the space program.

Shuttles were also expensive. The Endeavour, built to replace the Challenger, cost approximately $1.7 billion US, according to NASA. And the cost of an average launch was in the half-a-billion-dollar range. Critics said it would have been more efficient to have a selection of launch vehicles designed to accomplish specific jobs instead of a multi-purpose crewed vehicle.

"NASA's main mistake was putting too many eggs into one space travel basket," Matthews said. "It costs a lot more to send manned launch vehicles [into space]."

Important spinoffs

While costly, the shuttle program's 135 missions did drive advances in space-based research. They also opened up space travel to people from different countries and professions.

"Before the Shuttle, almost all the people sent on NASA missions were military test pilots," said Logsdon. "The shuttle program opened up the opportunity for scientists and engineers from other countries to go into space."

Canada seized on the chance to participate in the shuttle program early on, and was responsible for what some consider to be one of the most important technological spinoffs of the program. The Canadarm robotic arm first travelled aboard Columbia during the second space shuttle mission in 1981 and was used to move payloads off the spacecraft. The device's success led to much more active Canadian participation in the shuttle program, with Marc Garneau becoming Canada's first man in space in 1984.

The space shuttle Canadarms have been used to support astronauts on spacewalks, like this one to service the Hubble telescope in 1993. NASA photoThe Canadarm also played an essential role in repairing a faulty mirror and replacing components on the Hubble Space Telescope over the course of five servicing missions between 1993 and 2009. As a result of the repairs, the Hubble became a research powerhouse, helping change black holes from theory to fact, providing measurements that helped establish the size and age of the universe, and offering evidence that the universe is expanding.

Canada continued to contribute its robotic expertise to the program. By 2001, the Canadarm-2 was launched into orbit on the International Space Station. In 2008, the Canadian-designed and built Dextre robot was sent into orbit. The latter was designed to perform many tasks that would otherwise require risky spacewalks.

"Canadian robotic manipulator technology is the single most important contribution of the shuttle program to future space exploration," Matthews said. "It's the most tangible benefit, because we've learned how to build and repair things in space on a large scale."

"If you eventually want to mine Helium-3 on the moon, or precious metals on asteroids, it won't be people in spacesuits with pickaxes and shovels doing the digging," he added. "It's going to be future versions of Dextre, operated by people in spacesuits."

Looking ahead

The shuttle program has also had important technological spinoffs here on Earth. They range from the technology behind Lasik eye surgery, to implantable heart pumps, to more efficient home insulation, to memory foam, and even new golf club technology.

These types of space-program spinoff benefits for the general population may continue, but the question is whether they will be the result of research funded by government or private enterprise. The end of the shuttle program means that for the first time in 50 years, the United States will no longer have a vehicle of its own to send humans into orbit. The Obama administration is also shifting the responsibility to the private sector for designing and building the next generation of spacecraft .

"It's a completely different paradigm," Matthews said. "Space has always been the realm of government."

Still, some say the end of the shuttle program is a boon for space travel, because it will take the focus off orbital trips and set the world's sights further away again.

Logsdon, for example, believes there should be a focus on developing the potential of the International Space Station (ISS) for the next decade. However, he also hopes for something more ambitious than relying on private companies to send spacecraft into the Earth's lower orbit.

"It's time for us to go back to the moon. The last time we left orbit was December 1972," Logsdon said.

Matthews agrees that the post-shuttle decades promise to be a completely new frontier for human space travel, but he's not sure precisely where we'll go next.

"It's difficult for me to tell what will happen," he said. "I'm only a simple rocket scientist."