NASA said Friday that astronauts aboard the international space station and space shuttle Atlantis woke up to a worrying sound–alarms indicating a fire and dangerous loss of pressure.

However, no serious trouble was detected after a check.

NASA said that depressurization-caution alarms sounded just after 8:30 p.m. ET Thursday, waking the shuttle and station crew. The flight control teams on the ground determined there was no depressurization and shut off ventilation fans.

NASA added that the crew was never in any danger, and teams on the ground are looking into the cause of the false alarm.

NASA also said that flight control teams at Mission Control in Houston, Texas were bringing the station back to normal soon after the alarms, but it was 10:15 p.m. by the time the crew was able to go back to sleep because they had to wait for the station’s ventilation system to be reactivated.

(article and photo source: CNN)