The price tag of the toilet NASA has just bought from Russia for the International Space Station (ISS) is raising eyebrows here on Earth, but US $19 million could be a small price for a system so ergonomically adapted to conditions in a micro-gravity habitation with no elbow room.

A space toilet looks like the regular washroom version, but there the resemblance ends. Aim is no less important during calls of Nature than it is on Earth, so leg restraints, thigh bars and foot straps are added to the system to hold an astronaut in place. And there is no flush, a pointless feature for a toilet in microgravity because water would travel everywhere but where it was meant to go.

A flush would be too extravagant as well as pointless because it would waste water. The supply ship brings only 119 gallons of fresh water every few months, according to Canada’s Ottawa Citizen newspaper, a scant supply for a crew of three. It is in such short supply that astronauts use edible toothpaste so they don't have to rinse and spit and no-rinse shampoo. The article explains that a space toilet employs a vacuum instead of a flush, and pumps urine to a filtering system that turns it into drinking water.

There is only one toilet on board the ISS for three people. The newspaper explains that space bosses don’t want crew members lining up to go. The new big-ticket model will give the ISS two toilets to meet the needs of an expanding crew. It is being increased to six in 2009 to hasten completion of the ISS before NASA retires the shuttle fleet the following year.  

A report on the public television network PBS sees the second toilet as an essential backup for the existing model, also Russian built, which has been in orbit since late 2000. A breakdown of the sole toilet would be a dangerous disaster. The risk of disease would be added to the logistical horrors of coping without a toilet. Studies show some microbes thrive in microgravity and confined spaces, meaning infections could easily spread to everyone aboard.

Sources: Ottawa Citizen; PBS