A SpaceX Falcon 9 rocket gently touched down in the Atlantic Ocean on Wednesday, after an attempted landing at Kennedy Air Force Base in Florida went awry.

The reason for the “water landing,” in the words of SpaceX engineers, was due to a failed hydraulic pump that controls the grid fin, a large directional fin used to guide the rocket into an upright landing on Earth after its reentry into the atmosphere.

A video camera mounted on the rocket’s first stage caught the spin-out while it descended toward Florida. In the seconds between the reentry and landing burns, the Falcon 9 began to spin and hit transonic speed.

This was the video from the rocket’s point-of-view in that moment:

And this is video from a camera that Musk shared on Twitter. It’s unclear where the camera was positioned, but you can see plant life in the lower-right-hand corner:

The crowd of SpaceX engineers who watch the landings live from its Hawthorne, California, headquarters can be heard collectively gasping. Then, a video producer at SpaceX cut away from the footage. Watch:

SpaceX CEO Elon Musk posted the grid fin explanation on his Twitter account a few moments later and said the rocket appeared undamaged and was transmitting data. A recovery ship had been sent to retrieve it.

A SpaceX Falcon 9 grid fin.
A SpaceX Falcon 9 grid fin.

Musk also posted on Twitter that there was no back-up system in place because landing the rocket wasn’t mission-critical. “Given this event, we will likely add a backup pump & lines,” replied Musk to a Twitter user.

Musk also said the video cut-away was a mistake. “We will show all footage, good or bad,” he posted on Twitter. He added that the rocket may be re-used for an “internal SpaceX mission.” Musk posted the full splashy video — watch it above — on his Twitter at 2:29 p.m. Eastern Wednesday.

The mission, named CRS-16, was the 20th for SpaceX in 2018, and all missions up to this one had gone off without a hitch. It was also the 16th time SpaceX has sent cargo to the International Space Station.

The rocket had been used once before: On February 19, 2017 (654 days ago if you’re keeping score at home), it took off from Florida and landed back at LZ-1, where it was scheduled to return today. That first mission was also one that went to the ISS, the CRS-10 mission.

The Dragon Cargo capsule, filled with 5,600 pounds of science experiments and supplies, is on its way to the ISS, scheduled to arrive on Saturday.