Stranded Boeing astronaut reports ‘strange pulsing noises’ coming from doomed space capsule in eerie urgent call to Nasa

ONE of the stranded Nasa astronauts aboard the International Space Station (ISS) has reported a "strange noise" coming from the Starliner spacecraft he arrived on.

Butch Wilmore, 61, contacted the Johnson Space Centre in Houston on Saturday to alert them of the sound just days before the faulty vessel is sent back to Earth.

"I've got a question about Starliner," Wilmore said on the radio, Ars Technica first reported.

"There's a strange noise coming through the speaker... I don't know what's making it."

Mission control managed to link up to the audio inside Starliner, which has been docked on the ISS for nearly three months after an eight day mission went awry.

Wilmore then put his microphone up to the speaker inside Starliner, to give ground controllers a better listen.

"Alright Butch, that one came through," Mission control radioed up to Wilmore.

"It was kind of like a pulsing noise, almost like a sonar ping."

Wilmore replied: "I'll do it one more time, and I'll let y'all scratch your heads and see if you can figure out what's going on... Call us if you figure it out."

In a statement today, a Nasa spokesperson confirmed that the pulsing sound was an audio configuration issue.

"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 spokesperson said.

They added that crew are asked to contact mission control when they hear sounds in the communication system.

Unmanned return

Starliner is set to be undocked from the ISS on September 6, before it attempts an unmanned return to Earth on autopilot.

On August 24, Nasa revealed plans for Wilmore and his Starliner crewmate Sunita Williams, 58, to return to Earth on a SpaceX Dragon capsule.

The Dragon capsule will ferry Nasa astronaut Nick Hague and Russian cosmonaut Aleksandr Gorbunov to the ISS on September 24, picking up Wilmore and Wilmore for a return flight.

Wilmore and Williams flew to the ISS for an eight-day mission in early June, following a launch that was plagued by helium leaks and delays.

The spacecraft safely delivered the pair to the ISS, but had sprung more helium leaks and five of its 28 thrusters had failed by the time it arrived.

After the doomed Boeing capsule, which had $4billion of taxpayer money funneled into it, was deemed to risky for a crewed return, Wilmore and Williams were looking at an up to six month stay.

The duo are both on their third mission to the ISS, and were feared to suffer the devastating effects of space on the human body should they not see home until 2025.

Astronauts lose between 1% and 2% of bone density for every month spent in space, according to , which can have life-altering knock-on effects.