Pruitt works at the Marshall Space Flight Center in Huntsville, Alabama on the International Space Station’s (ISS) water recovery system. Her goal is to devise the most efficient way to extract drinking water from astronauts’ urine.

Urine contains around 95% water (the rest is made up of the body’s waste chemicals) so the more water that can be recycled from the two ISS space toilets, the less that needs to be brought up from Earth on costly supply-runs.

In the reception area outside Pruitt’s laboratory, there is a small exhibition area devoted to urine. Jars of the stuff are displayed on a shelf – they range in colour from a perfectly regular-looking light yellow, through brown to a disconcerting black.

Sophisticated process

Disturbingly, the jar labelled “American pre-treated urine” is a much lighter colour than the jar with the Russian label.

What does this say about Russian urine?

“There’s nothing wrong with the Russians,” says Pruitt reassuringly, “they still pee like everyone else.”

The dark inky liquid is not, in fact, Russian urine but Russian urine with ingredients added as part of the treatment process.