The computers controlling air supply, oxygen levels and the guidance for the International Space Station have been brought back online after astronauts fixed a glitch in the system.
Problems occurred shortly after the Space Shuttle Atlantis docked with the station and installed a new solar power array.
Officials were worried that if the problem was not fixed by the time Atlantis was due to leave, the station may have had to be abandoned.
It appears that the fault was caused by the surge protectors on the computer's electrical systems. The new solar array may have caused the protectors to shut the computers down as a safety measure.
The astronauts used jumper cables to bypass the protectors and, when tested, the computers worked normally.
Atlantis has now undocked and is returning to Earth. It will bring home Nasa astronaut Suni Williams, who has just set the record for the longest female space flight at 189 days.
"I am saddened to say goodbye, but that means progress is being made and it is time for the International Space Station to grow a little more," she said.
"Exploration is not necessary or always logical. It is something that comes from inside each and every one of us.
"I believe we are all born with this curiosity called exploration. Human spaceflight is just one aspect of exploration, but it is the one that I have been intimately familiar with over the past six months."
Space Station computers back online
By Iain Thomson on Jun 21, 2007 5:59PM