A new Cold War appears to be brewing between Russian and U.S. astronauts in outer space - over a loo and an exercise bike.
The tricky issue of who uses whose lavatory on the International Space Station only came to light when a Russian cosmonaut complained he was no longer allowed to use a U.S. toilet and exercise bike.
Gennady Padalka aired his frustrations in an interview with a Russian newspaper before he headed off into space.
All smiles: The current crew on the ISS. But cosmonaut Gennady Padalka, left, says splitting rules over loos, food and exercise bikes has lowered morale onboard. His U.S. colleague is in the back row, centre
He blamed officious busybodies back down on Earth for the squabbles over how the international crew divided food, toilets and exercise facilities. And he said the lack of sharing was lowering morale.
Before he and his crew blasted off for space last Thursday, Padalka told the Novaya Gazeta newspaper that in the past, they"d all shared food rations out in space which had helped with bonding. However, this was now frowned upon.
Padalka said before the mission he"d asked the Americans if he could use their gym to stay fit.
"They told me: "Yes, you can." Then they said "No." Then they hold consultations and they approve it again," he said.
Padalka conceded that compared to the Russians, the U.S. astronauts were living the high-life in space with access to a luxurious American astro-loo and "tastier" food.
But he said he was embarrassed by the arguments.
How astronauts go to the toilet in zero gravity
Designed to be as much as possible like those on Earth, each space toilet - properly called a Waste Collection System - can be used by both men and women.
The units use flowing air instead of water to move waste through the system.
Solid wastes are compressed and stored onboard, and then removed after landing.
Wastewater is vented to space on the Space Shuttle, although future systems may recycle it, such as they do on the International Space Station.
The air is filtered to remove odour and bacteria and then returned to the cabin.
The Zvezda module toilet (circled), built by the Russians on the International Space Station - the Americans apparently have a deluxe astro-loo
The space station"s Russian toilet uses fans and airflow in place of gravity to collect solid and liquid waste for disposal. The gas-liquid separator is part of the liquid waste system.
It weighs about 35lb and is about 1.5ft long and 8in wide and tall.
Technology has come a long way since 1961 when the very first space toilet was the simple "do it in your suit" version
Cold war between Russia and U.S. over sharing toilets on International Space StationCold war between Russia and U.S. over sharing toilets on International Space Station