NASA handout showing the International Space Station in March 2008.

It's bad enough when the toilet gets clogged at home; it could be a lot more serious in space, especially with visitors on the way.

NASA said Wednesday that the liquid waste handling function of the toilet at the International Space Station (ISS) had malfunctioned the day before and that the three astronauts aboard had to use the toilet at the Soyuz capsule moored at the station.

While one of the crew was using the Russian-made toilet last week, the toilet motor fan stopped working after “it made a loud noise”, according to NASA. Since then, the liquid waste gathering part of the toilet has been working on-and-off.

Fortunately, the solid waste collecting part is functioning normally.

Eventually the two Russians and one American at the orbiting station were able to fix up a "urine bypass" on the ISS toilet, located on the Zvezda module, the National Aeronautics and Space Administration said.

NASA spokeswoman Nicole Cloutier told reporters that the space shuttle Discovery, scheduled to arrive at the ISS Monday with seven astronauts aboard, would be carrying toilet parts to help repair the station's prickly plumbing.

"It's not really an emergency, they have many options available if they need," Cloutier said from the Johnson Space Center in Texas.

"There is another toilet ready to fly in the fall, in order to have two toilets on board for when they'll have the expanded crew of six" at the ISS, she said.