A space toilet or zero-gravity toilet is a

toilet A toilet is a piece of sanitary hardware that collects human urine and feces, and sometimes toilet paper, usually for disposal. Flush toilets use water, while dry or non-flush toilets do not. They can be designed for a sitting position popu ...

that can be used in a weightless environment. In the absence of weight, the collection and retention of liquid and solid waste is directed by use of airflow. Since the air used to direct the waste is returned to the cabin, it is filtered beforehand to control odour and cleanse bacteria. In older systems, wastewater is vented into space, and any solids are compressed and stored for removal upon landing. More modern systems expose solid waste to

vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or " void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often ...

pressures to kill bacteria, which prevents odor problems and kills

pathogens In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a ger ...

Background

Astronauts say that they are most often asked how they go to the bathroom in space. In space,

weightlessness Weightlessness is the complete or near-complete absence of the sensation of weight. It is also termed zero gravity, zero G-force, or zero-G. Weight is a measurement of the force on an object at rest in a relatively strong gravitational fie ...

causes fluids to distribute uniformly around human bodies.

Kidneys The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; bloo ...

detect the fluid movement and a physiological reaction causes the humans to need to relieve themselves within two hours of departure from

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's sur ...

. The space toilet was thus the first device activated on shuttle flights, after astronauts unbuckled themselves.

Mechanism

In the absence of gravity, space toilets use air flow to pull urine and feces away from the body and into the proper receptacles. A new feature of the space toilet is the automatic start of air flow when the toilet lid is lifted, which also helps with odor control. By popular (astronaut) demand, it also includes a more ergonomic design requiring less clean-up and maintenance time, with corrosion-resistant, durable parts to reduce the likelihood of maintenance outside of the set schedule. Less time spent on plumbing means more time for the crew to spend on science and other high-priority exploration focused tasks. The crew use a specially shaped funnel and hose for urine and the seat for bowel movements. The funnel and seat can be used simultaneously, reflecting feedback from female astronauts. The space toilet seat may look uncomfortably small and pointy, but in microgravity, it is ideal. It provides ideal body contact to make sure that everything goes where it should. The space toilet includes foot restraints and handholds for astronauts to keep themselves from floating away. Everyone positions themselves differently while “going”, and consistent astronaut feedback indicated that the traditional thigh straps were a hassle. Toilet paper, wipes, and gloves are disposed of in water-tight bags. Solid waste in individual water-tight bags is compacted in a removable fecal storage canister. A small number of fecal canisters are returned to Earth for evaluation, but most are loaded into a cargo ship that burns up on re-entry through Earth’s atmosphere. Currently, fecal waste is not processed for water recovery, but NASA is studying this capability.

Basic parts

There are four basic parts in a space toilet: the liquid-waste vacuum tube, the vacuum chamber, the waste storage drawers, and the solid-waste collection bags. The liquid-waste vacuum tube is a long rubber or plastic hose that is attached to the vacuum chamber and connected to a fan that provides suction. At the end of the tube is a detachable urine receptacle, which comes in different versions for male and female astronauts. The male urine receptacle is a plastic funnel in width and about deep. A male astronaut urinates directly into the funnel from a distance of away. The female funnel is oval and is wide at the rim. Near the funnel's rim are small holes or slits that allow air movement to prevent excessive suction. The vacuum chamber is a cylinder about deep and wide with clips on the rim, where waste collection bags may be attached and a fan that provides suction. Urine is pumped into and stored in waste storage drawers. Solid waste is stored in a detachable bag made of a special fabric that lets gas (but not liquid or solid) escape, a feature that allows the fan at the back of the vacuum chamber to pull the waste into the bag. When the astronaut is finished, he or she then twists the bag and places it in a waste storage drawer. Samples of urine and solid waste are frozen and taken to Earth for testing.

Designs

Space Shuttle Waste Collection System

The toilet used on the

Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program n ...

is called the Waste Collection System (WCS). In addition to air flow, it also uses rotating fans to distribute solid waste for in-flight storage. Solid waste is distributed in a cylindrical container, which is then exposed to vacuum to dry the waste. The WCS required many hours of training. For urination, a hose was used. For defecation, with a diameter for the hole in the seat—much smaller than in a conventional toilet—the user's bottom needed to be exactly centered on the seat. NASA built a simulator with a video camera in the hole; those training used a crosshair to learn how to position their bodies, while other astronauts watched and made jokes. Liquid waste is vented to space. During

STS-46 STS-46 was a NASA Space Shuttle mission using and was launched on July 31, 1992, and landed on August 8, 1992. Crew Backup crew Crew seating arrangements Mission highlights The mission's primary objectives were the deployment of ...

, one of the fans malfunctioned, and crew member Claude Nicollier was required to perform in-flight maintenance (IFM). An earlier, complete failure, on the eight-day STS-3 test flight, forced its two-man crew (

Jack Lousma Jack Robert Lousma (born February 29, 1936) is an American astronaut, aeronautical engineer, retired United States Marine Corps officer, former naval aviator, NASA astronaut, and politician. He was a member of the second crew, Skylab-3, on t ...

and Gordon Fullerton) to use a fecal containment device (FCD) for waste elimination and disposal.

International Space Station

Astronauts Mark Vande Hei and Shane Kimbrough work on a new toilet

There are two toilets on the

International Space Station The International Space Station (ISS) is the largest Modular design, modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos ( ...

, located in the ''Zvezda'' and ''Tranquility'' modules. They use a fan-driven suction system similar to the

WCS. Liquid waste is collected in containers. Solid waste is collected in individual micro-perforated bags, which are stored in an aluminum container. Full containers are transferred to

Progress Progress is the movement towards a refined, improved, or otherwise desired state. In the context of progressivism, it refers to the proposition that advancements in technology, science, and social organization have resulted, and by extension w ...

for disposal. An additional Waste and Hygiene Compartment is part of the

Tranquility Tranquillity (also spelled tranquility) is the quality or state of being tranquil; that is, calm, serene, and worry-free. The word tranquillity appears in numerous texts ranging from the religious writings of Buddhism, where the term ''passaddhi'' ...

module launched in 2010. In 2007, NASA purchased a Russian-made toilet similar to the one already aboard ISS rather than develop one internally. On May 21, 2008, the gas–liquid separator pump failed on the 7-year-old toilet in Zvezda, although the solid-waste portion was still functioning. The crew attempted to replace various parts, but was unable to repair the malfunctioning part. In the interim, they used a manual mode for urine collection. The crew had other options: to use the toilet on the Soyuz transport module (which only has capacity for a few days of use) or to use urine-collection bags as needed. A replacement pump was sent from Russia in a

diplomatic pouch A diplomatic bag, also known as a diplomatic pouch, is a container with certain legal protections used for carrying official correspondence or other items between a diplomatic mission and its home government or other diplomatic, consular, or other ...

, so that

Space Shuttle Discovery Space Shuttle ''Discovery'' ( Orbiter Vehicle Designation: OV-103) is one of the orbiters from NASA's Space Shuttle program and the third of five fully operational orbiters to be built. Its first mission, STS-41-D, flew from August 30 to ...

could take it to the station as part of mission

STS-124 STS-124 was a Space Shuttle mission, flown by Space Shuttle ''Discovery'' to the International Space Station. ''Discovery'' launched on 31 May 2008 at 17:02 EDT, moved from an earlier scheduled launch date of 25 May 2008, and landed safely at ...

on June 2.

Other designs

The

Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

/ Russian

Space Station A space station is a spacecraft capable of supporting a human crew in orbit for an extended period of time, and is therefore a type of space habitat. It lacks major propulsion or landing systems. An orbital station or an orbital space station ...

Mir ''Mir'' (russian: Мир, ; ) was a space station that operated in low Earth orbit from 1986 to 2001, operated by the Soviet Union and later by Russia. ''Mir'' was the first modular space station and was assembled in orbit from 1986 to&n ...

's toilet also used a system similar to the WCS. While the

Soyuz spacecraft Soyuz () is a series of spacecraft which has been in service since the 1960s, having made more than 140 flights. It was designed for the Soviet space program by the Korolev Design Bureau (now Energia). The Soyuz succeeded the Voskhod spacecr ...

had an onboard toilet facility since its introduction in 1967 (due to the additional space in the Orbital Module), all Gemini and

Apollo Apollo, grc, Ἀπόλλωνος, Apóllōnos, label=genitive , ; , grc-dor, Ἀπέλλων, Apéllōn, ; grc, Ἀπείλων, Apeílōn, label=Arcadocypriot Greek, ; grc-aeo, Ἄπλουν, Áploun, la, Apollō, la, Apollinis, label= ...

spacecraft required astronauts to urinate in a so-called "relief tube", in which the contents were dumped into space, while fecal matter was collected in specially-designed bags. The facilities were so uncomfortable that, to avoid using them, astronauts ate less than half the available food on their flights. The

Skylab Skylab was the first United States space station, launched by NASA, occupied for about 24 weeks between May 1973 and February 1974. It was operated by three separate three-astronaut crews: Skylab 2, Skylab 3, and Skylab 4. Major operations ...

space station, used by NASA between May 1973 and March 1974, had an onboard WCS facility, which served as a prototype for the Shuttle's WCS, but also featured an onboard shower facility. The Skylab toilet, which was designed and built by the Fairchild Republic Corp. on Long Island, was primarily a medical system to collect and return to Earth samples of urine, feces and vomit, so that calcium balance in astronauts could be studied. Even with the facilities, astronauts and cosmonauts for both launch systems employ pre-launch bowel clearing and

low-residue diet A low-residue diet is a diet intended to reduce certain constituents of the bowel, often with consequence for functional behaviour of the bowel. It may be prescribed for patients with ailments or functional gastrointestinal disorders mitigated ...

s to minimize the need for

defecation Defecation (or defaecation) follows digestion, and is a necessary process by which organisms eliminate a solid, semisolid, or liquid waste material known as feces from the digestive tract via the anus. The act has a variety of names ranging f ...

. The Soyuz toilet has been used on a return mission from

NPP Zvezda JSC Research & Development Production Enterprise Zvezda, or R&D PE Zvezda (russian: Научно-производственное предприятие "Звезда", НПП Звезда, Nauchno-Proizvodstvennoye Predpriyatiye "Zvezda", NPP ...

is a Russian developer of space equipment, which includes zero-gravity toilets. A $23 million next-generation space toilet called the Universal Waste Management System (UWMS) is being developed by NASA for Orion and the International Space Station. The UWMS is the first space toilet designed specifically for women as well as men, easing the use of space toilets for women and use for stool and urine at the same time. It is designed to be fully automated, quieter, lighter, more reliable, more hygienic and more compact than previous systems. Among its innovations, the UWMS relies on a

3D printing 3D printing or additive manufacturing is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer co ...

technique to incorporate metals including

Inconel Inconel is a registered trademark of Special Metals Corporation for a family of austenitic nickel-chromium-based superalloys. Inconel alloys are oxidation-corrosion-resistant materials well suited for service in extreme environments subjected ...

, Elgiloy, and

titanium Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion i ...

that can withstand the acids used to treat urine within the toilet. The UWMS was first delivered to the ISS in October 2020. File:Toilet device on Soyuz spacecraft.jpg, Toilet device on Soyuz spacecraft File:Space Shuttle toilet 01.JPG, Space Shuttle toilet File:Russian space toilet.JPG, Russian space toilet used in space station Mir File:MOL toilet.jpg, A mockup of the toilet that would be carried on MOL File:Zvezda toilet.jpg, Zero-gravity toilet on the

in the

Zvezda Service Module ''Zvezda'' (russian: Звезда, meaning "star"), ''Salyut'' DOS-8, also known as the ''Zvezda'' Service Module, is a module of the International Space Station (ISS). It was the third module launched to the station, and provided all of t ...

File:Waste and hygiene compartment in the Destiny laboratory of the International Space Station - 20090412.jpg, Space toilet inside Node 3, after relocation from the US lab File:ISS Universal Waste Management System (3).jpg, ISS Universal Waste Management System

References

{{DEFAULTSORT:Space Toilet Toilets Spacecraft life support systems