Concern is caused by strange noise which he spotted on Saturday in the Starliner space capsule o Butch Wilmore, one of two astronauts stranded on the International Space Station (ISS).

Butch Wilmore and Suni Williams were scheduled to spend eight days on the ISS, but will remain finally eight monthsafter a series of technical difficulties with Boeing’s spacecraft led to the difficult decision not to use it to bring the two American astronauts back to Earth. The two astronauts will return to Earth aboard Elon Musk’s SpaceX spacecraft in February. This is another blow to the prestige of Boeing, which already faces repeated failures in its aircraft.

According to the Daily Mail, Wilmore raised concerns about a “strange” noise last Saturday at the Johnson Space Center in Houston, just days before the capsule began its unmanned return trip to Earth.

“I have a question about the Starliner. A strange noise is heard from the speaker. I didn’t know if you can connect to the Starliner… I don’t know what’s causing him,” Wilmore said. After two attempts, the Space Center recorded the sound.

“Butch, this is over. It was something like a pulsating noise, almost like a sonar ping” was emphasized by Earth. “I’ll let you all scratch your heads and see if you can figure out what’s going on,” Wilmore replied.

Canadian former astronaut Chris Hadfield, who has served as commander of the International Space Station, expressed concern over the strange event. “There are a number of noises I’d rather not hear inside my spaceship, including what the Boeing Starliner is making right now,” he wrote on X, accompanying his post with the corresponding audio.