As if being stranded in space for the foreseeable future wasn’t enough … one of the astronauts stuck aboard the ISS just sent NASA audio of an ominous noise coming from their faulty Boeing Starliner aircraft.

In audio first reported by Ars Technica, astronaut Butch Wilmore can be heard communicating with Johnson Space Center in Houston … telling mission control, “I’ve got a question about Starliner. There’s a strange noise coming through the speaker … I don’t know what’s making it.”

Mission control configured a way for Butch to play the sound through the phone … and after one failed attempt at hearing it, mission control confirmed, “Butch, that one came through. It was kind of like a pulsating noise, almost like a sonar ping.”

Butch played the audio once again for good measure, telling NASA, “I’ll do it one more time and let you all scratch your heads and see if you can figure out what’s going on.”

Houston confirmed they will be passing along the recording and will let Butch know what they find.

As we previously reported … Wilmore and fellow astronaut Suni Williams have been stranded on the International Space Station since June 6, due to Starliner’s thruster troubles and helium leaks … after what was supposed to be a week-long stay.

Starliner is scheduled to undock from the ISS and attempt to land back on Earth on autopilot.