The new crew aboard the International Space Station are facing their first major hardware problem with the failure of one of four massive gyroscopes that control and stabilise the platform's flight.

The loss is serious, but will not affect the station's operations, a spokesman for the American space agency (Nasa) says.

Losing a gyro is a big deal... but from a risk perspective right now we're in good shape

Flight Director Paul Hill

The device will have to be replaced as it cannot be repaired in space.

The failure comes a day after the American space shuttle Endeavour, with the new Expedition Five on board, docked with the space station.

The shuttle also transported three tons of supplies and equipment for scientific experiments.

Major component

The loss of function of the desk-sized 363-kilogramme (800-pound) gyro emerged after astronauts reported a loud, growling noise inside the International Space Station.

Nasa thinks it may be a year before a shuttle can accommodate a new device - known as a Control Moment Gyro (CMG) - in its cargo bay.

The station's old crew go home next week

The orbiting station can function with two gyros, which are solar-powered.

Even if three failed, it could use thrusters for stability, although that would use precious propellant that has to be flown up from Earth.

"To lose a CMG is a big deal; this is a major component, but from a risk perspective right now we're in good shape," Flight Director Paul Hill told reporters.

"We are still one failure away."

Preparing for record

The station's new crew is due to stay for four and a half months.

Commander Valery Korzun and Flight Engineers Peggy Whitson and Sergei Treschev arrived on Friday.

Endeavour is due to take the outgoing crew - Yuri Onufrienko, Carl Walz and Daniel Bursch - back to Earth on 17 June.

By the time they touch down, Walz and Bursch will have set a new endurance record for Americans in space, with 194 days in orbit.