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Engineers at Mission Control Centers Houston and Moscow are evaluating whether Russia's new Poisk mini-module may have somehow triggered a false depressurization alarm that cost the 12 space travelers on the International Space Station (ISS) and the space shuttle Atlantis a little sleep Thursday night.

The crews were awaked by the alarm at 8:36 p.m. EST after station systems incorrectly indicated a rapid depressurization. Ventilation fans automatically shut down in the station's pressurized modules, which triggered a secondary false alarm in Europe's Columbus laboratory when dust from the ventilation system apparently set off a smoke alarm.

"Everything is back to normal," said a spokesman at Johnson Space Center. "The crew was never in any danger. Flight control teams are looking into the cause of the initial false alarm."

Astronaut Frank Lien, the capsule communicator in Houston when the alarm tripped, later suggested to Expedition 21 Commander Frank De Winne that it may have been associated with Poisk, which docked to the Russian side of the station Nov. 12 (Aerospace DAILY, Nov. 11). The pressurized mini-module, which will serve as a docking port and airlock, was launched from Baikonur Cosmodrome on a Soyuz rocket for an automatic rendezvous and docking.

The combined crews remained awake while the ventilation system was reactivated and stabilized, a process that took about an hour. During that time they were cautioned against pockets of carbon dioxide buildup. To accommodate the lost sleep time, they were allowed to slip their wakeup time back a half hour, until 4:28 a.m. EST Friday.

Crew members showed no apparent ill effects from the lost sleep today, as they worked to transfer pressurized cargo from the shuttle to the station. They were able to advance the transfer work in the mission timeline because controllers have decided they will not need to use the robotic arms for a focused inspection of the orbiter's heat shield.

A review of inspection data turned up no ascent damage that warranted a second look, clearing the time set aside for the focused inspection, according to lead ISS flight director Brian Smith.

Photo credit: NASA