To Boldly Go: The Science Behind Pooping in Space


What Mike Mullane remembers most clearly about having his first bowel movement in space is the blast of cold air greeting his exposed rectum. Over the course of three week-long NASA shuttle missions in the 1980s—two for Discovery, one for Atlantis—Mullane was forced to answer nature's call six or seven times in zero gravity. Each time, he would have to strip naked, close a flimsy curtain around a titanium commode, position his buttocks to form a perfect seal around a 4-inch opening, and then follow a checklist posted nearby to make sure no fecal particles escaped into the deck—all while his sphincter insisted on clamping shut to escape the freezing temperatures.

"It was a complex operation," Mullane tells Mental Floss. "On Earth, I'm fast. My wife is amazed I can be in and out of the bathroom in one minute for a number two. On the shuttle, it would take 30."

While the industrial toilet was a far cry from five-star hotel room seat warmers and bidets, it also improved by magnitudes the ordeal of emptying one's intestines in zero gravity. Prior to 1972, the men of the Gemini and Apollo missions braved poop bags that they would stick to their rear ends, then manually knead the contents with an antibacterial solution so the gases wouldn't detonate the collection; more than one crew has been terrorized by rogue turds hovering in the air.

Coming up with a practical way of replicating the earthbound poop experience took many years, many engineers, and a whole lot of ingenuity. While few explorers like to discuss it, taking a space dump is its own kind of heroism.

Consider one early—and discarded—solution for waste collection in space, which someone dubbed the "sh*t mitt." Donald Rethke likens it to "those long rubber gloves veterinarians use for insemination." The idea, he tells Mental Floss, was that the astronaut could poop in their own hand and then turn the glove inside-out, creating instant containment of the feces.

Now 80, Rethke is a retired engineer from Hamilton-Standard, a NASA subcontractor working through Northrop Grumman that spent decades refining or pioneering life-support systems for space explorers. Rethke, who embraces his industry nickname of "Doctor Flush," says that handling poop simply wasn't much of a concern due to the brief trips taken by pioneering astronauts: They could just go before they left. But as missions grew longer, it became necessary to address personal waste—urine and bowel movements—without dealing with the discomfort of diapers.

A NASA training commode
A training toilet with a camera positioned inside so astronauts can learn how to best angle their buttocks.
National Geographic, YouTube

For the 1965–66 Gemini excursions, which were planned to prove humans could survive for several days or weeks in space, astronauts were told to use a condom-like sheath that would direct urine into a bag. For feces, they were to use a pouch with a 1.5-inch opening and an adhesive strip around the edge to help prevent fecal matter from escaping. A fellow crew member would be told to stand by and watch to make sure no waste escaped into the capsule.

"It kind of looked like an upside-down top hat," Mullane says. Though they pre-dated his missions, they were on board his shuttles in case of equipment failure. "We never had to use them, thank God."

But the occupants of Gemini and Apollo did, and most found it unpleasant for reasons unrelated to crapping in a bag. When gravity is lacking, surface tension becomes a dominant force. So urine and feces that would separate from the body on Earth thanks to gravity tend to cling to the skin's surface in space.

"If you stick your finger into a glass of water and lift it up, water flows off," Mullane explains. "But in weightlessness, the attraction of the molecules of the fluid will pull it into a ball. If you leave fluid alone, it will form a perfect sphere. Touch it, and will stick to you."

The same goes for poop. The bags had tiny finger covers built in so users could flick and scrape errant flecks away from their cheeks. Then they'd mix in a chemical to kill the bacteria so the gases wouldn't expand in the sealed bag and create an explosive biohazard.

"Well, it's in a small, like a ketchup, a little plastic container like you find ketchup in in restaurants, in a cafeteria or something, it's like that," Apollo astronaut Russell Sweickhart told a reporter in 1977. "You tear the slit across the top, being careful not to squeeze it so the stuff comes out, and then you drop that into the fecal container, and then seal the fecal container. Then you squeeze it through the, you know, externally, you know, which forces it out of the container, and then you mix it by massaging the fecal bag. It's really fun when it's still warm."

If everything went well, it was merely disgusting. If it didn't, as the following transcript excerpt from the 1969 Apollo 10 mission demonstrates, it could be highly disruptive:

Tom Stafford: Give me a napkin quick. There's a turd floating through the air.

John Young: I didn't do it. It ain't one of mine.

Gene Cernan: I don't think it's one of mine.

Stafford: Mine was a little more sticky than that. Throw that away.

Young: God Almighty.

"When the Apollo astronauts came back," Rethke says, "they wanted sit-down toilets."

A look at the ISS bathroom
The "orbital outhouse" inside the International Space Station.

While modesty may not have been an achievable goal, astronauts needed some semblance of routine. (Some shuttles were equipped with kitchen tables, even though nothing in zero gravity could be perched on one.) But the comforts of a domestic commode had little application in space. No water could be used: It would run everywhere. And unlike gravity-assisted toilets, a shuttle john would have to address the surface tension issue that enticed poop to come out in curls instead of straight down, mashing itself against the skin.

The solution, according to Rethke, was gentle suction. "Or, as I like to call it, air entrainment," he says. In its simplest form, it's getting the poop Hoovered away from your bottom using air flow as a substitute for gravity.

Rethke says the idea was already on the table courtesy of General Electric (GE) when Hamilton-Standard began working on a zero gravity toilet, and that his job was one of refinement that lasted through the 1980s and 1990s. "The concept of separating solids from the body was already in the bag, no pun intended. It was just the best way. Most of my effort was how to do that economically."

NASA had previously toyed with a variety of designs, including one 1971 model that was mounted vertically on a wall to conserve space. Another took the feces and pulped it, a model not unlike evacuating into a blender. This, engineers realized, created the potential for fecal "dust," or powdered particles of poop, that could contaminate the cabin of spacecraft. By using air entrainment, hardly anything could escape the bowl—and if it did, it wouldn't be atomized to the point of being a biological hazard. Instead, a fan and vacuum system was used to encourage the waste to settle at the bottom of the waste tube.

Air entrainment made one frustrating demand of its users: proper anal positioning. With a 4-inch opening compared to a conventional toilet's 18 inches, astronauts had to align themselves up perfectly in order to avoid any escaping feces. To train astronauts heading for space, NASA set up a commode with a camera mounted inside. (You were not expected to make a deposit.) Users could gauge their perch based on freckles or other skin marks in relation to the seat. Properly docked, they could poop on target, but it took practice.

"It's hard to know where your a-hole is when the hole is that narrow," Mullane says.

Minor complaints aside, NASA's work was ready in time for the 1973 debut of Skylab, the first space station, and the 1981 launch of Columbia, the first shuttle to reach space. After realizing the pulverizing model wasn't going to work due to the fecal dust issue and other malfunctions that led to problems on 10 of the shuttle's first 11 voyages, a redesigned system less prone to clogging was introduced in the mid-1980s.

Urinating, according to Mullane, was never any big deal. Men and women use a form-fitting cup and gentle suction to empty their bladder. "Pretty simple," he says. "But solid waste, that was kind of like going in a camper toilet."

On the Atlantis and Discovery, the space commode had foot rests and thigh straps so astronauts could remain secure to the seat while doing their business. They'd typically opt to strip naked in the event any soiling occurred. To the right was a hand lever; pushed forward, it slid open the tube underneath their buttocks. "You never wanted to open that before sitting on it," Mullane says. Doing so could release the previous user's residual fecal matter into the air.

Once Mullane was strapped in, he would open the tube cover and feel the rush of cold air hit his rear. The air moved 360 degrees while a fan underneath—loud enough to mask sounds of elimination—pulled waste away from the body and into a container that would store the matter until the shuttle returned. Toilet paper would go in a separate bag. By the time Mullane got dressed, cleaned the toilet's edges, and exited, 30 minutes had passed.

Surprisingly, the intimate size of the shuttle didn't contribute to any fragrant evidence. "They did a really good job of filtration," Mullane says. "You never smelled anything."

Rethke improved on this in the early 1990s by compacting the discarded feces at the bottom, reducing the need for storage space. (To make sure it would stay sealed, Rethke once kept a feces-filled container in his office for a year.)

Small tweaks aside, the space toilet doesn't follow the update schedule of, say, an iPhone. What Rethke redesigned and what Mullane used is, by and large, what's still in use on the International Space Station (ISS) today. But instead of bringing waste back, it's discarded so it burns up in the atmosphere.

Future movements may prove more difficult to handle. With the advent of long-duration travel, possibly to Mars, on the horizon, space exploration will have to deal with the issue of waste management when there's virtually no chance of Earthbound assistance.

"When toilets fail [on Earth], it's a real pain," Mullane says. "Just imagine that on Mars. I have no idea how they're going to do that."

Someone might. In early 2017, the HeroX platform crowned a winner in its Space Poop Challenge, which crowdsourced ways to handle waste in space when an explorer is in a spacesuit and away from a fixed toilet for long periods. The winning idea—a suit hatch that can be used to insert inflatable bedpans and diapers—earned inventor Thatcher Cardon a $15,000 prize. If it works, it'll assist in an integral part of exploring beyond our atmospheric borders. In space, everyone needs to go.

Additional Sources: Riding Rockets: The Outrageous Tales of a Space Shuttle Astronaut

More Details Emerge About 'Oumuamua, Earth's First-Recorded Interstellar Visitor

In October, scientists using the University of Hawaii's Pan-STARRS 1 telescope sighted something extraordinary: Earth's first confirmed interstellar visitor. Originally called A/2017 U1, the once-mysterious object has a new name—'Oumuamua, according to Scientific American—and researchers continue to learn more about its physical properties. Now, a team from the University of Hawaii's Institute of Astronomy has published a detailed report of what they know so far in Nature.

Fittingly, "'Oumuamua" is Hawaiian for "a messenger from afar arriving first." 'Oumuamua's astronomical designation is 1I/2017 U1. The "I" in 1I/2017 stands for "interstellar." Until now, objects similar to 'Oumuamua were always given "C" and "A" names, which stand for either comet or asteroid. New observations have researchers concluding that 'Oumuamua is unusual for more than its far-flung origins.

It's a cigar-shaped object 10 times longer than it is wide, stretching to a half-mile long. It's also reddish in color, and is similar in some ways to some asteroids in own solar system, the BBC reports. But it's much faster, zipping through our system, and has a totally different orbit from any of those objects.

After initial indecision about whether the object was a comet or an asteroid, the researchers now believe it's an asteroid. Long ago, it might have hurtled from an unknown star system into our own.

'Oumuamua may provide astronomers with new insights into how stars and planets form. The 750,000 asteroids we know of are leftovers from the formation of our solar system, trapped by the Sun's gravity. But what if, billions of years ago, other objects escaped? 'Oumuamua shows us that it's possible; perhaps there are bits and pieces from the early years of our solar system currently visiting other stars.

The researchers say it's surprising that 'Oumuamua is an asteroid instead of a comet, given that in the Oort Cloud—an icy bubble of debris thought to surround our solar system—comets are predicted to outnumber asteroids 200 to 1 and perhaps even as high as 10,000 to 1. If our own solar system is any indication, it's more likely that a comet would take off before an asteroid would.

So where did 'Oumuamua come from? That's still unknown. It's possible it could've been bumped into our realm by a close encounter with a planet—either a smaller, nearby one, or a larger, farther one. If that's the case, the planet remains to be discovered. They believe it's more likely that 'Oumuamua was ejected from a young stellar system, location unknown. And yet, they write, "the possibility that 'Oumuamua has been orbiting the galaxy for billions of years cannot be ruled out."

As for where it's headed, The Atlantic's Marina Koren notes, "It will pass the orbit of Jupiter next May, then Neptune in 2022, and Pluto in 2024. By 2025, it will coast beyond the outer edge of the Kuiper Belt, a field of icy and rocky objects."

Last week, University of Wisconsin–Madison astronomer Ralf Kotulla and scientists from UCLA and the National Optical Astronomy Observatory (NOAO) used the WIYN Telescope on Kitt Peak, Arizona, to take some of the first pictures of 'Oumuamua. You can check them out below.

Images of an interloper from beyond the solar system — an asteroid or a comet — were captured on Oct. 27 by the 3.5-meter WIYN Telescope on Kitt Peak, Ariz.
Images of 'Oumuamua—an asteroid or a comet—were captured on October 27.

U1 spotted whizzing through the Solar System in images taken with the WIYN telescope. The faint streaks are background stars. The green circles highlight the position of U1 in each image. In these images U1 is about 10 million times fainter than the faint
The green circles highlight the position of U1 in each image against faint streaks of background stars. In these images, U1 is about 10 million times fainter than the faintest visible stars.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF

Color image of U1, compiled from observations taken through filters centered at 4750A, 6250A, and 7500A.
Color image of U1.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF

Editor's note: This story has been updated.

Watch NASA Test Its New Supersonic Parachute at 1300 Miles Per Hour

NASA’s latest Mars rover is headed for the Red Planet in 2020, and the space agency is working hard to make sure its $2.1 billion project will land safely. When the Mars 2020 rover enters the Martian atmosphere, it’ll be assisted by a brand-new, advanced parachute system that’s a joy to watch in action, as a new video of its first test flight shows.

Spotted by Gizmodo, the video was taken in early October at NASA’s Wallops Flight Facility in Virginia. Narrated by the technical lead from the test flight, the Jet Propulsion Laboratory’s Ian Clark, the two-and-a-half-minute video shows the 30-mile-high launch of a rocket carrying the new, supersonic parachute.

The 100-pound, Kevlar-based parachute unfurls at almost 100 miles an hour, and when it is entirely deployed, it’s moving at almost 1300 miles an hour—1.8 times the speed of sound. To be able to slow the spacecraft down as it enters the Martian atmosphere, the parachute generates almost 35,000 pounds of drag force.

For those of us watching at home, the video is just eye candy. But NASA researchers use it to monitor how the fabric moves, how the parachute unfurls and inflates, and how uniform the motion is, checking to see that everything is in order. The test flight ends with the payload crashing into the ocean, but it won’t be the last time the parachute takes flight in the coming months. More test flights are scheduled to ensure that everything is ready for liftoff in 2020.

[h/t Gizmodo]