HOUSTON — NASA’s Mission Control, assisted by the six-member crew of the International Space Station, scrambled on Feb. 19 to overcome a nearly 3-hr. satellite communications loss with the U.S. segment of the orbiting science laboratory that was triggered by an onboard computer transition during a ground-managed software upload.

Air-to-ground exchanges through NASA’s Tracking and Data Relay Satellite System stopped abruptly at 9:45 a.m. EST during an intentional transition from the backup to the primary computer for the upload of new software designed to expand communications for scientific research activities under way on the station. The backup had the new software and the transition was to permit an upgrade of the primary computer, says Josh Byerly, a NASA ISS program spokesman.

A configuration error blocked the voice, telemetry and video exchanges through the high-data-rate satellite communications system. The station’s critical attitude and environmental control systems were unaffected. The communications upgrade activities have been under way since last year.

A little more than an hour later, at 11 a.m. EST, UHF voice communications were re-established through Russian ground stations, permitting NASA’s flight control team to send the station’s crew instructions for aligning another backup computer to the TDRS network. Normal air-to-ground communications through TDRS resumed at 12:34 p.m. EST.

“The station is still flying straight. Everyone is in good shape,” ISS commander Kevin Ford assured Mission Control during the brief UHF communications pass. “There wasn’t anything unexpected other than lots of caution and warning tones.”

Ford leads a crew that includes three Russians, a Canadian and a second NASA astronaut.

As the computer activities were about to get under way, Canadian astronaut Chris Hadfield offered an ironic observation over Twitter: “Good morning, Earth,” he tweeted. “Today, we transition the space station’s main computers to a new software load. Nothing could possibly go wrong.”

As the process unraveled, Hadfield was back with another observation involving Hal Getzelman, the crew’s veteran Mission Control communications officer.

“Hal!” the Canadian said, in a reference to the infamous HAL 9000 character from “2001: A Space Odyssey.” “The irony, as life imitates art,” he said.