Updated

It was a mission-critical element: the size of NASA astronauts' manhood. Seriously. The Houston Chronicle resurrects the fascinating historical tidbit by way of the Science Channel's Moon Machines documentary series, in which engineer Donald Rethke explained the very precise nature of early space diapers.

The Maximum Absorbency Garment system, donned by Gemini and Apollo astronauts, featured one very specific element: a sleeve likened to a condom with a hole at the tip that enabled the men to urinate into a pouch with a one-way valve in their suits.

Three sleeve sizes were available, small, medium, and large. And astronauts couldn't fib, explains Rethke. If they decided to order the next size up, the sheath wouldn't fit snugly, and liquid could potentially leak out, causing damage.

To make the process a little less embarrassing, the sizes were later renamed: large, gigantic, and humongous. Motherboard notes that the urination issue was first brought to the fore by Alan Shepard, who spent hours in the Freedom 7 capsule in advance of a quick 15-minute "suborbital hop." Denied permission to leave the capsule, he opted to pee in his suit—forcing Mission Control to turn off his biomedical sensors until the flow of oxygen in the suit dried the pee, allowing the sensors to be switched on.

Today's astronauts enjoy actual restrooms, though MAG systems are provided to astronauts who are operating outside space vehicles. (Other unusual NASA history: A scientist "stole" a satellite from the agency in 1983—and is ready to give it back.)

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