Houston ? The failure of Russian computers that control the international space station’s positioning have NASA managers considering another extension of space shuttle Atlantis’ visit to the orbiting outpost, officials said Wednesday.

Since the computers failed earlier this week, thrusters on the docked space shuttle have been fired periodically to help maintain the space station’s positioning.

NASA managers hoped to have the computers back up before Atlantis and its seven crew members undock from the space station next Tuesday. But if the computers aren’t functioning, NASA may look into extending the space shuttle’s stay a day or two.

Atlantis’ mission, originally scheduled for 11 days, has been extended by two days already so that astronauts can go on a spacewalk to repair a thermal blanket covering an engine pod that peeled up during launch.