Mission control teams are working to assess systems affected by a power loss aboard the International Space Station early Sunday morning. The station’s three crew members were not in any danger, but it did turn an off-duty day into a full work shift.
About 1 a.m. EST, one of the power channels of the P4 solar array electrical system went down because of a glitch with a device known as a direct current switching unit. It controls power distribution from the solar array to the battery systems and other hardware. The glitch resulted in a temporary loss of communications, and shut down some equipment, including a few science facilities and heating units and control moment gyroscope #2. The station never lost orientation control, but it operated most of the day with two of four gyros. Control moment gyroscope #3 previously had been powered down.
Flight controllers restored power to nearly all affected systems and equipment by Monday morning. They are still investigating what caused the glitch, but they believe it was an isolated event.