Fifty three years ago on May 5, 1961, NASA astronaut Alan Shepard blasted off in a Freedom 7 capsule atop a Mercury-Redstone rocket to become the first American in space.

Though his sub-orbital flight only lasted 15 minutes, it was a historical moment in the Space Race against the Soviet Union.

However, a little known fact about this flight is what took place before it. Shepard sat in the rocket for five hours because of delays, and the astronaut really had to use the restroom.

"Man, I got to pee," Shepard said to launch control.

That really wasn't an option for Shepard, who was already strapped in tight and ready for launch. And NASA wasn't prepared either because officials figured the mission would be short enough to avoid a scenario like this. Shepard, who donned a shiny silver spacesuit and was covered in wired medical sensors, couldn't just pee on himself.

Image: NASA

However, NASA didn't have a choice — Shepard, who had been in the spacecraft for a total of eight hours, really had to go.

So, on that first flight to space, Shepard went into orbit wearing a wet spacesuit.

And NASA also learned a lesson: Never send someone to space without a "plan pee." Shortly after that first flight, the agency hired James McBarron to oversee the company that designed the spacesuit and add a urinary collection device.

Mercury-Redstone rocket that transported Alan Shepard into space being launched on May 5, 1961. Image: AP Photo/Associated Press