NASA provided an inadvertent insight into its training techniques when it accidentally broadcast audio that sounded like an emergency on the International Space Station.

There wasn't a crisis, however, the audio made it sound as though something had gone terribly wrong and a crew member was suffering from decompression sickness.

Decompression sickness is an affliction known to SCUBA divers. It occurs when dissolved gases form bubbles inside body tissues. It can happen during or shortly after an ascent without sufficient decompression stops. In the case of the ISS training, it was likely due to an extravehicular activity scenario - perhaps a bad suit seal during airlock decompression.

It can also be fatal. Judging by the audio broadcast, the affected crew member was not having a great time, with his condition described at one point as "tenuous."

NASA later clarified the situation via a post on X, saying what had been heard was actually just a training exercise.

"There is no emergency situation going on aboard the International Space Station," the space agency said.

"This audio was inadvertently misrouted from an ongoing simulation where crew members and ground teams train for various scenarios in space and is not related to a real emergency. The International Space Station crew members were in their sleep period at the time. All remain healthy and safe."

While NASA has not provided the transcript, the broadcast remains available via the ISS live video feed. Although the video was interrupted, a female voice can be heard working through the incident, saying at one point: "Whatever you can do is better than doing nothing."

NASA has a long history of using simulations to test crew and ground personnel. The Apollo 11 mission was arguably saved by some thorough training in landing scenarios and which alarms would require an abort, according to Gene Kranz's excellent memoir Failure Is Not an Option.

However, accidentally broadcasting this training on a public channel without warning was unfortunate.

As was the delay before the agency confirmed that all was well aboard the ISS. ®

https://www.theregister.com//2024/06/13/nasa_iss_emergency_broadcast/