- Astronaut Butch Wilmore first reported the mysterious noise on Saturday.
- NASA said the pulsing sound was the result of feedback on the speakers.
- It's the latest in a saga that unexpectedly kept two astronauts in space since June.
On Saturday, NASA astronaut Butch Wilmore radioed NASA Mission Control reporting that he was hearing a heavy, pulsing sound coming from the Boeing Starliner spaceship.
"There's a strange noise coming through the speaker," Williams said in a recording obtained by Ars Technica. "I don't know what's making it," he later added.
Wilmore launched on the Boeing Starliner in June with astronaut Suni Williams. The two were supposed to return to Earth after about a week, but instead have been living on the International Space Station for over two months.
The Starliner spacecraft malfunctioned during flight. Five of its 28 Reaction Control System (RCS) thrusters shut down. It also suffered leaks in the helium supply, which is used to pressurize its propulsion system. But the mysterious noises Wilmore heard had nothing to do with either of those issues.
On Monday, NASA revealed the ominous noise was simply a feedback issue between the speakers on the Boeing Starliner and the ISS where it's docked.
"The space station audio system is complex, allowing multiple spacecraft and modules to be interconnected, and it is common to experience noise and feedback," NASA said on X.
NASA added that the noise will not affect the crew on board.
Starliner is scheduled to return to Earth uncrewed on Saturday, September 7th.
NASA determined it was unsafe to transport Williams and Wilmore back to Earth.
The two astronauts are scheduled to return in February 2025 on board a SpaceX Crew Dragon, instead — nearly eight months after they launched.