The Boeing Starliner capsule that has been plagued with technical issues and left astronauts temporarily stranded aboard the International Space Station alarmed astronauts by emitting some very peculiar sounds on Saturday.

"I've got a question about Starliner," NASA astronaut Butch Wilmore radioed mission control to report. "There's a strange noise coming through the speaker … I don't know what's making it."

The sound, as revealed in a released recording, came from the docked module, and bore a strong resemblance to sonar pings.

Former ISS commander Chris Hadfield remarked on X (formerly Twitter) that it was not a comforting noise to hear aboard a spacecraft.

Given how problematic the capsule has proven, the sound was a little worrying. Wilmore, currently stranded with NASA astronaut Sunita Williams due to Starline thruster issues and helium leaks, requested NASA investigate the source.

It took a little time, but NASA has come through, and the sound is thankfully nothing to be alarmed about.

"A pulsing sound from a speaker in Boeing's Starliner spacecraft heard by NASA astronaut Butch Wilmore aboard the International Space Station has stopped. The feedback from the speaker was the result of an audio configuration between the space station and Starliner," NASA told Jeff Foust of Space News in an email.

"The space station audio system is complex, allowing multiple spacecraft and modules to be interconnected, and it is common to experience noise and feedback. The crew is asked to contact mission control when they hear sounds originating in the comm system. The speaker feedback Wilmore reported has no technical impact to the crew, Starliner, or station operations, including Starliner's uncrewed undocking from the station no earlier than Friday, Sept. 6."

The Starliner will return to Earth where it will be thoroughly examined. Wilmore and Williams will remain aboard the ISS, where they will work as official members of the Expedition 71/72, scheduled to return home to Earth in February 2025.