SpaceX founder Elon Musk is not exactly known for being an emotionally expressive guy.

Musk, when he appears in public, has a pretty laid-back demeanor, but that calm exterior goes out the window in a newly released clip from National Geographic. The nearly four minute video shows Musk watching the first stage of a Falcon 9 rocket land back in Florida.

The landing, which happened almost exactly one year ago on Dec. 21, 2015, marked the first time the private spaceflight company has landed a rocket stage back on solid ground.

It was an exciting moment for space nerds everywhere, but Musk in particular can be seen gasping, grimacing and basically just freaking out as he waits to learn the fate of his rocket in the new footage.

In December, Musk said that he initially thought the rocket exploded as it was coming back down to the ground. He mistook the sonic boom of the rocket's re-entry for the sound of an actual explosion.

The new video bears this out.

Musk looks up and says something to the effect of "this is bad" as he watches the rocket coming back in for its (ultimately smooth) landing.

After watching the booster come down to its pad, Musk runs back inside to check out a video feed showing the booster upright back at the Cape.

"What? Holy smokes, man," Musk said in the video.

While SpaceX made many attempts before, the December landing was the first time the company managed to land the boost stage of its Falcon 9 back on Earth after launching to space. Previous attempts centered on landing stages on a drone ship floating in the ocean, but none were successful.

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Since that first, historic landing, SpaceX has has safely brought back six boosters to Earth after delivering payloads to space.

The company lands these rocket stages in order to develop a fleet of reusable launchers that could greatly reduce the cost of spaceflight in the future.

At the moment, however, the company is in a tight spot.

One of SpaceX's Falcon 9 rockets exploded on its pad ahead of an engine test in September, destroying the satellite it was expected to carry to orbit.

SpaceX's launch schedule is currently on hold as the company gets to the root of the issue that caused the major accident. At the moment, SpaceX is planning to launch again sometime in January.