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Soyuz ASU

Some information about the Soyuz ASU, toilet – a somewhat indelicate but necessary topic!

The waste disposal system functions similarly to the ISS toilet in the Russian segment – using a vacuum system – though everything is necessarily more compact. It resides in the Soyuz Orbital Module. The descriptions below are derived from those at Charles Simonyi’s site (I can’t link to the relevant pages directly as it is a Flash-animated site – grrr!).

For urination (with the control panel switch set to #1) a replaceable funnel is used. The waste is sucked into a collection tank (there are ten in the module), and the air circulates through a charcoal filter before being sent back into the cabin. According to this post at CollectSPACE.com, “women use a sanitary-napkin-type pad which absorbs fluid,” which doesn’t sound too appealing! If the electric air pump fails, a device with a rubber-bulb handpump serves as a backup.

For defecation (switch set to #2), a disposable bag is put into a container, which has an air suction tube connected to the container (the airflow goes through the bag and a charcoal filter). A carton cover needs to be removed from the bag before insertion; it contains some sanitizing chemicals and toilet paper (the latter is also removed). The user positions the device against their posterior. After finishing, a string around the edge of the bag snaps a rolled rubber cover into place, hermetically sealing the contents. After securely tying it with rubber ties (similar to the ones used to tie up the lining of the Sokol spacesuit), the bag insert is removed and put into another rubberized bag. This is placed into yet another bag, hermetically sealed and placed in a waste container with other rubbish (it will all burn up when the Orbital Module is discarded upon descent).

SoyCOM Manual: Ассенизационно-Санитарная Установка (АСУ) (Waste Management System)

АСУ function is collection, isolation and stowage of the crew’s physiological wastes.

АСУ composition:

In the БО:

In the СА:

АСУ Technical Characteristics:

Diagrams & photo links

Some photos of the Soyuz toilet at Skorina.com: 03.24 20Jun00; 03.25 20Jun00; 05.06 21Jun00.

The following diagrams are from « Когда невесомость в тягость, о чем молчат космонавты» (“When weightlessness is a burden, about which the cosmonauts keep silent”), Russian Popular Mechanics, June 2006 – on the development of Russian space toilets. (Thanks to “Captain David” for finding this!)