Space toilet

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A space toilet, or zero gravity toilet, is a toilet that can be used in a low gravity environment. In the absence of gravity the collection and retention of liquid and solid waste is directed by use of air flow. Since the air used to direct the waste is returned to the cabin, it is filtered beforehand to control odor and cleanse bacteria. In older systems, waste water is vented into space and any solids are compressed and stored for removal upon landing. More modern systems expose solid waste to vacuum to kill bacteria, which prevents odor problems and kills pathogens.

Mission Specialist Claude Nicollier reviews the repair manual for the WCS on STS-46

1 Current designs
2 See also
3 References
4 External links

[edit] Current designs

[edit] Space Shuttle Waste Collection System

The toilet used on the Space Shuttle 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.^[1]^[2] Liquid waste is vented to space. During STS-46, one of the fans malfunctioned, and crew member Claude Nicollier was required to perform in-flight maintenance (IFM).

Diagram of the elements of the Space Shuttle WCS^[3]

[edit] International Space Station

The toilet on the International Space Station located in the Zvezda module uses a fan-driven suction system similar to the Space Shuttle WCS. Liquid waste is collected in 20 liter containers. Solid waste is collected in individual micro-perforated bags which are stored in an aluminum container.^[4] Full containers are transferred to Progress for disposal. An additional Waste and Hygiene Compartment is scheduled be part of the Node 3 module to be launched in 2010. In 2007, NASA purchased a Russian-made toilet similar to the one already aboard ISS rather than develop one internally.^[5]

On May 21, 2008, the 7-year-old toilet's gas liquid separator pump failed, although the solid waste portion is still functioning. The crew attempted replacing various parts, but was unable to repair the malfunctioning part. In the interim, they used a manual mode for urine collection.^[6] The crew has other options: 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.^[7] A replacement pump was sent from Russia in a diplomatic pouch so that Space Shuttle Discovery could bring it to the station as part of mission STS-124 on June 2nd.^[8]^[9]^[10]

[edit] Other spacecraft

The Soviet/Russian Space Station Mir's toilet also used a system similar to the WCS.^[11]

Apollo and Soyuz require toilet facilities due to mission length, although astronauts for both launch systems employ pre-launch bowel clearing and low-residue diets to minimize the need for defecation.^{[citation needed]} The Soyuz toilet has been used on a return mission from Mir.^[11]

NPP Zvezda is a Russian developer of space equipment, which includes zero gravity toilets (Assenisation Sanity Unit ASU-8A). The recently (2008) failed unit abroad the ISS was of this type.