The space capsule that took the first moonwalkers on their historic adventure is getting ready to take off on another trip — its first tour of the United States in more than 40 years.

The Apollo 11 command module is the spacecraft that Neil Armstrong, Buzz Aldrin and Michael Collins rode in to the moon and back in 1969. To celebrate the upcoming 50th anniversary of that achievement, the Smithsonian's National Air and Space Museum is sending the space capsule to four different museums around the country.

It's the first time the space capsule, called Columbia, will have left the museum since it opened to the public in 1976.

The traveling exhibit also will include objects such as the helmet and gloves that Aldrin wore during his moonwalk, a "rock box" that the astronauts used to bring back some of the first samples ever from a heavenly body and the watch that Collins wore during his lonely time orbiting the moon while Aldrin and Armstrong explored the lunar surface.

"This is the spacecraft that brought the three astronauts home from the first landing on the moon, so it's one of the Smithsonian's most important artifacts," says Michael Neufeld, a senior curator at the museum.

In 1970 and 1971, before it came to the Smithsonian, the capsule went on a 50-state tour. This time around, it will be going here:

Space Center Houston — Oct. 14, 2017–March 18, 2018
St. Louis Science Center — April 14–Sept. 3, 2018
Senator John Heinz History Center, Pittsburgh — Sept. 29, 2018–Feb. 18, 2019
The Museum of Flight, Seattle — March 16–Sept. 2, 2019
Those museums were picked for a variety of reasons, including the fact that they had the capacity to display such a large, heavy object.

"All of the venues actually had to submit engineering documentation to make sure that the floor load was one that could support not just the Columbia, but also the rest of the traveling exhibit," says Kathrin Halpern, a project director at the Smithsonian Institution Traveling Exhibition Service. "It's a very special artifact. And it does weigh a lot. The command module, on its traveling ring, is over 13,600 pounds."

She says this is likely a once-in-a-lifetime opportunity to see the command module outside of Washington, D.C. When it returns, Columbia will be the centerpiece of a new "Destination Moon" exhibit that will open in 2021 to tell the story of lunar exploration from ancient times to today.