Washington - Mysterious problems with Russian computers that control the positioning of the International Space Station may have been caused by sensitivity to noise or static caused by variations in electric signals, NASA said Thursday evening. US and Russian scientists had been working overtime to determine why three computers critical to ISS operations had crashed, raising the possibility that the already extended Space Shuttle Atlantis mission could be lengthened further.
The evacuation of the ISS could be a possibility if the computers that stabilize the ISS remained down, but the chance of that was very slim, NASA director Bill Gerstenmaier said.
The electronic signals causing the problem could be eliminated with electromagnetic fields or other devices, ISS flight director Mike Suffredini said at the NASA control centre in Houston, Texas.
The signals are comparable to the interference caused by a mobile phone near a television set.
The problems may have been unleashed by a new solar array installed on the station Monday, but are not an inherit design problem with the panel, Suffredini said.
The problems concerned NASA enough to take energy saving measures on the Atlantis so that it could stay in space another extra day if it is needed to stabilize the ISS. The robot arm and other non- necessary systems were turned off, shuttle flight director Cathy Koerner said.
The Russian computers are used to hold ISS on course so that it circles the Earth at a steady level and keeps its solar panels pointed toward the sun to have enough energy.
The ISS is not endangered as long as a gyroscope in the US part of the station can hold it on course. If that were also to fail, the Atlantis could provide stabilization.
The computer problems trivialized a problem with a heat blanket on Atlantis that is to be pushed back into place on a spacewalk Friday.
