These are the continuing voyages...

On this day in 2011, the Space Shuttle Atlantis launched on the last mission of the Shuttle program, bringing a close to 30 years of Shuttle flights. Atlantis is pictured here at liftoff from Pad 39A during the STS-135 mission.

While the Mercury, Gemini, and Apollo programs only lasted a few short years, the Shuttle was part of our lives for decades.

Project Mercury went from 1958-1963, Gemini lasted from 1965 to 1966, and the Apollo program's glorious existence was from the first uncrewed flight in 1966 to the final Moon landing in 1972. After Apollo, there were the Skylab missions and the last flight of Apollo-era hardware during the Apollo-Soyuz mission in 1975.

The Space Shuttles were part of my life from the time I was born until I was in college. They were companions that gave ordinary Americans a front-row seat in space exploration for three decades.

It's easy to romanticize the missions from the early days of NASA's history, the rapid progress, the giant leaps, they were incredible achievements. The Shuttle Program wasn't as glamorous as those first missions, but it's still an important part of our space history.

STS-135 was one of the smaller crewed missions, with only 4 astronauts traveling to the International Space Station during this mission. Astronauts Christopher Ferguson, Doug Hurley, Sandra Magnus, and Rex Walheim spent 8 days at the ISS, delivering supplies and equipment.

Also pictured here, the SpaceX Falcon 9 rocket launching the Dragon capsule Endeavour and astronauts Doug Hurley and Bob Behnken to the International Space Station for the SpaceX Demo-2 mission.

Nearly nine years passed between the final Shuttle flight and the recent SpaceX Commercial Crew launch. Both missions launched from the historic Pad 39A at Kennedy Space Center. SpaceX has modified the pad to support Falcon 9 and Falcon Heavy, so the Rotating Service Structure pictured in the first picture has been dismantled as its no longer used. Here's to more exciting decades of space exploration and research!

Picture credit- NASA/SpaceX