´óÏó´«Ã½

Two Russian cosmonauts and an American astronaut are stuck in space for longer than planned.

Nasa's Frank Rubio and cosmonauts Sergey Prokopyev and Dmitry Petelin travelled in a Russian Soyuz spacecraft to the International Space Station (ISS) in September last year.

The three spacemen were meant to use the same Soyuz craft to travel back to Earth in March, but a micrometeoroid - which is a tiny speck of dust or rock travelling incredibly fast through space - is thought to have hit and damaged the spaceship, delaying their journey home.

The vehicle - known as MS-22 - showed signs of damage when in December it began spraying coolant from a tiny hole into space.

Nasa TV captured dramatic images of white particles streaming out of the capsule like snowflakes.

The coolant helps to control temperatures inside the crew compartment of the spacecraft. Without it temperatures in the spaceship can rise to a very warm 30 - 40 degrees Celsius.

Without the coolant, the craft would be uncomfortably hot for the astronauts and not at an ideal temperature for all the instruments and computers onboard.

In the event of an emergency on the ISS, the damaged Soyuz could still be used like a lifeboat - so that the crew could escape quickly. Nasa has also discussed using a Space X Dragon capsule if needed.

Russia's federal space agency Roscosmos has decided to launch an empty Soyuz to the space station in February to bring Rubio, Prokopyev and Petelin back to Earth.

The damaged ship will then undock without a crew and return to Earth, landing in Kazakhstan.

However, the three spacemen can only leave once a replacement crew arrives at the space station.

And that mission will involve a new spaceship - a (not yet ready) upgrade to the Soyuz craft.

"The plan is for Frank and Dimitri and Sergey to stay on board for several more months until they come home, probably late September," said Dina Contella from Nasa.

It means Rubio, Prokopyev and Petelin will have to wait onboard the ISS for much longer than expected - extending their stay in space to one whole year - something no Nasa astronaut has ever done.