The Rocket Was Ready. The Astronaut Was Not.
On the morning of May 5, 1961, Alan Shepard climbed into the Freedom 7 capsule at around 5:15 a.m. for a scheduled 7:20 a.m. liftoff. Clouds and technical glitches pushed the launch back to 9:34 a.m. That is four hours inside a sealed pressure suit, lying on your back, with no way out and no plan for what to do if nature called.
Shepard asked Mission Control for permission to urinate. Engineers refused at first: biosensor electrodes could short-circuit if the suit got wet. When it became clear there was no other option, they switched the sensors off. Lying supine with legs raised, the urine pooled against his lower back, soaked into his wool undergarment, and was gradually dried by circulating oxygen before liftoff. The man the world watched become the first American in space had spent part of his historic morning sitting in a puddle of his own making. NASA had simply assumed he could hold it for a fifteen-minute flight.
Why Simple Solutions Don’t Work
A spacesuit is a wearable pressure vessel that must stay airtight above the atmosphere, any modification letting fluid pass in or out is a potential failure point. Aviation had wrestled with this since the Lockheed U-2 began flying above 70,000 feet in August 1955. Early suits had no urine provision; later versions used an indwelling catheter. A 2010 survey of U-2 pilots at Beale Air Force Base found 60 percent reported problems including poor fit, leakage, and skin irritation. The CIA never passed this experience to NASA, so NASA started from scratch.
The Urine Collection Device
After Shepard’s flight, NASA hired James McBarron in June 1961 to solve the problem. Working with engineers Al Rochford and Joe Schmitt, McBarron’s team built the Urine Collection Device (UCD): a latex sleeve connected by rubber hose to a one-way valve and a polyethylene collection bag held against the body by an elasticized belt. The one-way valve was critical, without it, pressure fluctuations could drive fluid back the wrong way.
On February 20, 1962, John Glenn became the first American to orbit Earth and the first to use the standardized UCD, depositing approximately 756 ml. The average male bladder sends an urgent signal at around 400 ml and reaches capacity at roughly 600 ml. Glenn’s number was well past both, and that discrepancy was not a fluke.
What Microgravity Does to Your Bladder
On Earth, gravity pulls urine to the lowest point of the bladder, where nerve endings detect stretch and signal urgency when the organ is roughly two-thirds full. In microgravity, urine forms a sphere near the bladder’s center, pressing lightly and evenly on surrounding walls rather than pooling at the bottom. Stretch signals come much later, if at all, which is why Glenn produced 756 ml before feeling real urgency. In space, the bladder fills silently past its usual limit.
The Boot on the Moon
Apollo astronauts used a Urine Transfer System during orbital flight, venting most waste overboard. During moonwalks, the only option was a sealed polyethylene bag worn under the suit. Buzz Aldrin stepped onto the lunar surface on July 20, 1969, and has said he was the first person to urinate on the Moon, doing so on the ladder before touching down. The landing was unusually soft, Neil Armstrong set the module down so gently that the bottom rung sat higher than expected, and when Aldrin jumped, the jolt broke his UCD. For the remaining roughly two and a half hours of the moonwalk, urine collected in his boot.
Designing for Everyone
NASA admitted women to the astronaut corps in 1978, but the male UCD had no workable female equivalent. The solution was the Disposable Absorption Containment Trunk (DACT), a high-performance absorbent undergarment built for pressurized suits. It flew for the first time on April 4, 1983, aboard STS-6, with an entirely male crew, which reflects how NASA’s timeline worked. By 1988 the DACT had been succeeded by the Maximum Absorbency Garment, eventually adopted by astronauts of both sexes.
Setting the Record Straight
Two pieces of folklore are worth correcting. The claim that nurse Dee O’Hara improvised the original UCD from a condom and a girdle is inaccurate: according to research published by the American Physiological Society, Gus Grissom’s solution for his July 21, 1961 flight was two pairs of rubber incontinence pants layered over each other. The story that NASA officially renamed UCD sizes to “gigantic” and “humongous” to protect astronaut egos appears in a 2008 Science Channel documentary and in Michael Collins’ 1974 autobiography Carrying the Fire, but as an informal crew joke, not formal policy. Apollo 9 astronaut Russell Schweickart confirmed three sizes existed and that correct fit was genuinely important for the device to function.
What holds up is the basic picture: the most advanced engineering program in American history sent a man into space with no urine plan, then spent two decades building one from the ground up. Glenn’s UCD bag has been on display at the National Air and Space Museum ever since.