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Third spacewalk due to commence Spacewalk on amid computer woes
(about 1 hour later)
The third spacewalk of Nasa's latest shuttle mission to the International Space Station (ISS) is scheduled to begin on Friday at 1738 GMT. The third spacewalk of Nasa's latest shuttle mission to the International Space Station (ISS) has begun.
The crew are attempting to repair a thermal blanket on Atlantis that peeled back during launch.The crew are attempting to repair a thermal blanket on Atlantis that peeled back during launch.
However, the spacewalk could be overshadowed by ongoing computer problems on the ISS.However, the spacewalk could be overshadowed by ongoing computer problems on the ISS.
Nasa has confirmed that engineers have failed to reboot a Russian computer system that has crashed. Nasa says engineers have failed to reboot a Russian system that has crashed. It controls thrusters that point solar panels towards the Sun.
The computer system controls the thrusters that point the station's solar panels towards the Sun as it orbits around the Earth.
While the system is down, the ISS is relying on its four gyroscopes to maintain its orientation, but it can also use Atlantis's thrusters, if needed, while the shuttle is docked.While the system is down, the ISS is relying on its four gyroscopes to maintain its orientation, but it can also use Atlantis's thrusters, if needed, while the shuttle is docked.
Engineers in Russia and the United States have been trying to pinpoint the source of the problem, but so far to no avail.Engineers in Russia and the United States have been trying to pinpoint the source of the problem, but so far to no avail.
Engineers in Moscow are attempting to fix the problemsEngineers in Moscow are attempting to fix the problems
Nasa said the computers had briefly been brought back online, but they had since been turned off to allow troubleshooting to continue.Nasa said the computers had briefly been brought back online, but they had since been turned off to allow troubleshooting to continue.
Russian Mission Control chief Vladimir Solovyov said engineers had also disconnected the Russian oxygen-generating system, called Elektron, as it is dependent on the faulty computers. But he added that the station had enough oxygen for 90 days.Russian Mission Control chief Vladimir Solovyov said engineers had also disconnected the Russian oxygen-generating system, called Elektron, as it is dependent on the faulty computers. But he added that the station had enough oxygen for 90 days.
The lives of the crew are not thought to be in danger, and a Nasa official said there were no current plans to evacuate the space station.The lives of the crew are not thought to be in danger, and a Nasa official said there were no current plans to evacuate the space station.
Russian space officials said they were considering sending their cargo vessel Progress to the ISS earlier than scheduled to deliver spare parts for the computers, if the problems persisted.Russian space officials said they were considering sending their cargo vessel Progress to the ISS earlier than scheduled to deliver spare parts for the computers, if the problems persisted.
DelaysDelays
While the computer efforts continue, Atlantis crew members Jim Reilly and Danny Olivas will embark on the mission's third spacewalk. While the computer efforts continue, Atlantis crew members Jim Reilly and Danny Olivas are embarking on the mission's third spacewalk.
The first task will be to repair the shuttle's torn thermal blanket.The first task will be to repair the shuttle's torn thermal blanket.
A 10cm (4in) section of thermal blanket peeled back as the shuttle blasted off from Cape Canaveral on Friday.A 10cm (4in) section of thermal blanket peeled back as the shuttle blasted off from Cape Canaveral on Friday.
The blanket protects the shuttle from the intense heat of re-entering the atmosphere. Engineers think the blanket was loosened by aerodynamic forces during lift-off.The blanket protects the shuttle from the intense heat of re-entering the atmosphere. Engineers think the blanket was loosened by aerodynamic forces during lift-off.
Problems are persisting with the ISS computer systemProblems are persisting with the ISS computer system
The astronauts will also attempt to install a new vent for an oxygen system as well as assist in the retraction of a solar array during their 6.5 hour excursion.The astronauts will also attempt to install a new vent for an oxygen system as well as assist in the retraction of a solar array during their 6.5 hour excursion.
The crew of space shuttle Atlantis was originally due to spend 11 days at the ISS, but the mission has since been extended to 13 days to carry out the thermal shield repairs.The crew of space shuttle Atlantis was originally due to spend 11 days at the ISS, but the mission has since been extended to 13 days to carry out the thermal shield repairs.
The ongoing computer problems could also extend the mission by a further day.The ongoing computer problems could also extend the mission by a further day.
This was supposed to be the second shuttle mission of 2007, but a freak storm over the Florida launch site in late February caused hail damage to the shuttle and delayed the mid-March flight.This was supposed to be the second shuttle mission of 2007, but a freak storm over the Florida launch site in late February caused hail damage to the shuttle and delayed the mid-March flight.
Despite the delays, managers are confident they will be able to complete the ISS before the shuttles' 2010 retirement date.Despite the delays, managers are confident they will be able to complete the ISS before the shuttles' 2010 retirement date.
Nasa plans to fly 15 more missions to the station to deliver large components, spare parts and other supplies. In addition, one final servicing call to the Hubble Space Telescope is planned for September 2008.Nasa plans to fly 15 more missions to the station to deliver large components, spare parts and other supplies. In addition, one final servicing call to the Hubble Space Telescope is planned for September 2008.