A NASA astronaut heard a mysterious “pulsing noise” inside Boeing’s Starliner. What was it?

In 2024, Boeing’s Starliner capsule carried NASA astronauts Butch Wilmore and Suni Williams to the International Space Station (ISS). This visit was supposed to be short, but NASA and Boeing had to delay the return due to issues with thrusters and helium leaks.

While the capsule stayed docked at the station, Wilmore noticed a sound that didn’t seem right. Here’s what happened aboard the ISS.

On August 31, 2024, Wilmore was working inside the docked Starliner. He then heard an unfamiliar noise come through its speakers. Soon after, he radioed Mission Control to ask about it. “There’s a strange noise coming through the speaker,” he said. “I don't know what's making it.” 

Wilmore also held a device up to the speakers. With this, Mission Control, based at Johnson Space Center in Houston, was able to hear it directly too. The sound repeated at regular intervals. The team on the ground compared it to a “pulsing noise, almost like a sonar ping.”

The sound was first reported by Ars Technica, which referenced a recording posted to the NASA Spaceflight forum by Rob Dale. Commenting on this, former Canadian astronaut Chris Hadfield wrote on X, “There are several noises I’d prefer not to hear inside my spaceship, including this one that Boeing Starliner is now making.” You can watch the video via the direct link here.

Something similar also happened during the Apollo 10 mission. While the spacecraft was over the far side of the Moon and out of communication with Earth, the crew heard an odd "whistling sound." But this sound was eventually linked to radio interference. 

NASA later said the pulsing had stopped. The agency traced the speaker feedback to an audio configuration between the station and Starliner. It also explained why that kind of thing can happen.

“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. Crew members were also asked to contact mission control whenever they hear sounds from the comm system.

“The speaker feedback Wilmore reported has no technical impact on the crew, Starliner, or station operations, including Starliner’s uncrewed undocking from the station no earlier than Friday, Sept. 6”, added NASA.
After undocking, the capsule successfully made the trip home in about six hours, landing at White Sands Space Harbor in New Mexico. Wilmore and Williams also returned later aboard a SpaceX Dragon capsule in February 2025.