“There’s a strange noise coming through the speaker… I don’t know what’s making it.”

Strange Music

Over the weekend, stranded NASA astronaut Butch Wilmore heard bewildering sounds coming out of Boeing’s much-maligned Starliner, which carried him to the space station for what was supposed to be an eight-day trip that’s now got him stuck on the orbital outpost until next year after equipment failures on the shuttle.

“I’ve got a question about Starliner,” he told mission control in Houston over the radio. “There’s a strange noise coming through the speaker… I don’t know what’s making it.”

While NASA later confirmed that the source of the noise was mostly benign, it’s more of the type of story that Boeing has definitely been hoping will go away.

Its spacecraft, which has been docked at the International Space Station since early June, has already been plagued with technical issues. Helium leaks affecting its propulsion systems forced NASA to reevaluate the mission, concluding last month that it wasn’t safe enough for Wilmore and colleague Sunita Williams’ return. Instead, to the chagrin of Boeing, they’ll return on a future SpaceX trip.

While investigating the unusual situation, Wilmore held his microphone up to Starliner’s speakers.

“Alright Butch, that one came through,” Houston told Wilmore. “It was kind of like a pulsing noise, almost like a sonar ping.”

“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,” Wilmore radioed. “Alright, over to you. Call us if you figure it out.”

Bumps in the Night

The strange sounds, as shared by meteorologist Rob Dale, manifest as an ominous knocking noise.

Fortunately, unlike Boeing’s trouble with Starliner’s propulsion system, it doesn’t sound like it was anything particularly serious this time — though the explanation does read as fairly amateurish on Boeing’s part.

In a statement to Ars Technica on Monday, NASA said that the “feedback from the speaker was the result of an audio configuration between the space station and Starliner.”

“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 statement reads.

It’s not the first time astronauts have encountered strange noises coming from their spacecraft. For instance, China’s first astronaut Yang Liewei noticed strange sounds that sounded like “knocking an iron bucket with a wooden hammer” during his voyage in 2003. The noise later turned out to be decreasing air pressure triggering changes in the structure of the vessel.

Starliner is scheduled to make its return without Williams and Wilmore on board as early as Friday. The two astronauts are instead getting a ride from Boeing’s competitor SpaceX in February — an unfortunate end to a disastrous first crewed test flight.

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