The main computer on the International Space Station failed early Sunday, and subsequent multiple computer anomalies prompted communication blackouts. The one main computer has two backup systems, and NASA reported that the three command & control computers are switching between prime, backup and standby. A software issue is suspected, and diagnosis continues. The computer system is critical to all aspects of space station operation.
NASA reported that despite the computer issues, all ISS systems are performing normally and there are no concerns for the safety of the crew.
Bill Harwood at CBS News reported that the station’s command and control software was updated before the shuttle Endeavour’s flight to account for the new Tranquility module and it’s possible the computer failures, or transitions, are software related. Issues with computers in Tranquility also have been noted, but it’s not yet clear whether they are related to the command and control issues.
ISS Commander Jeff Williams called Mission Control at 9:55 a.m. EST “and confirmed there had been a primary and backup failure of the command and control computer,” said NASA TV commentator Pat Ryan. At that time, all indications were that two of the three computers were healthy. But then later, about 11 a.m. EST, there new data indicated there had been another computer transition, this time still with just two computers healthy.
Another transition occurred an hour later.
“But we are still in a situation currently where all three computers are healthy but the team here in mission control is still scratching its head and trying to determine what’s been causing the repeated transitions,” Ryan said. “There has been no impact to station life support systems while this was going on and the crew is in good shape.”
“We’re thinking we might need another day off,” said Williams, apparently in good spirits.
“Copy and concur, Jeff,” replied Stan Love in Houston. “We are talking in the room, we still do not know what has been causing these transitions. We are toying with the idea there might be something related to commanding. But we are not sure, it’s just speculation at this point.”