NASA has given the green light to an emergency space walk to repair a broken-down computer attached to the International Space Station (ISS).

Two astronauts will venture outside the ISS to replace the failed machinery which started showing signs of problems on Saturday.

Astronauts Commander Peggy Whitson and Flight Engineer Jack Fischer could set off on the space walk as early as Tuesday, NASA revealed.

When the computer failed, the ISS - worth £77 billion - was forced to rely on a backup system to send commands to its solar power system, radiators and other equipment.

Nasa disclosed that no danger to crew members had been presented by the faulty computer, and had had no impact on station activities.

A similar replacement spacewalk was carried out in April 2014.

The latest spacewalk is expected to last around two hours.