Elon Musk showed childlike joy during the first historic landing of a Falcon 9 reusable rocket booster. (Image credit: National Geographic)

Billionaire entrepreneur Elon Musk typically displays such an incredibly calm demeanor that it’s hard to imagine him getting excited about anything.

But in a newly released video, Musk makes an uncharacteristic display of emotion, ranging from dread to unbridled joy as he watches a Falcon 9 reusable rocket booster make its historic first landing at Cape Canaveral, Florida, on Dec. 21, 2015.

The video, released by National Geographic as part of its “Mars” miniseries coverage, shows never-before-seen footage of Musk and members of the SpaceX team during the historic booster landing. In an uncommon display of emotion and energy, Musk is seen running toward the control room exclaiming, “It’s standing up!”

While most large rocket designs feature a first stage that is discarded after each launch, the Falcon 9 first stage is designed to be reusable. After kicking the payload skyward, Falcon 9’s first stage descends back toward Earth with the help of thrusters and lands upright on a landing pad. (This is sometimes located on a barge, moving with the swells of the ocean.) The Falcon 9 is the first orbital rocket to ever successfully land a reusable first stage booster after launch.

Multiple Falcon 9 first stage boosters boosters crashed as they attempted to touch down on the landing platform, before SpaceX made its first successful touchdown. So it’s understandable when, in the video, Musk looks panicked as he runs from the control room to a place outside where he can watch the booster descend toward the landing platform after it separates from the second stage and payload.

“OK, this is bad,” Musk says as he looks skyward, his face twisted into a strained look. “This is potentially bad.”

But then the booster’s thrusters kick on with a great burst of fire, and the large metal cylinder begins to lower its legs as it approaches the landing site. Then, in a moment that steals the breath of the SpaceX employees looking on, the booster touches down and remains upright. With childlike joy, Musk runs toward the control room, not quite yelling, “It’s standing up!”

“Holy smokes, man,” Musk almost whispers as he stares in awe at the video feed of the booster, sitting quietly on the landing pad.

SpaceX has had multiple successful booster landings since that first one. (The video is not explicitly dated, but the footage of the SpaceX employees watching the launch and the footage of the rocket itself are from the December 2015 landing. The footage of the booster landing shows the rocket touching down on a land-based landing pad rather than a barge, which took place on Dec. 21 of that year).

National Geographic included the Musk video in its six-part TV series (which concluded Monday, Dec. 19) that is part fictional drama and part documentary, exploring humanity’s pursuit of Mars. Musk announced plans earlier this year to eventually help colonize the Red Planet. You can learn more about National Geographic’s “Mars” project and the International Mars Science Foundation at their multimedia website: www.MakeMarsHome.com.