On Saturday NASA Astronaut Butch Wilmore noticed some strange noises emanating from a speaker inside the Starliner spacecraft.
“I have a question about Starliner,” Wilmore radioed to Mission Control at Johnson Space Center in Houston. “There’s a strange noise coming through the speaker … I don’t know what’s causing it.”
Wilmore said he wasn’t sure if there was some anomaly in the connection between the station and the spacecraft that was causing the noise, or something else. He asked flight controllers in Houston to see if they could listen to audio inside the spacecraft. A few minutes later, Mission Control radioed back that they were connected via a “hard line” to listen to audio inside Starliner, which has now been docked to the International Space Station for nearly three months.
Wilmore, apparently floating in Starliner, moved his microphone to the speaker inside Starliner. Shortly afterward, a very distinctive sound was heard. “Okay, Butch, the sound is there,” Mission Control told Wilmore. “It was like a pulsing noise, almost like a sonar sound.”
Listen to a recording of the noises heard by Butch Wilmore.
“I’ll do it one more time and let you all scratch your heads and see if you can figure out what’s going on,” Wilmore replied. The strange, sonar-like sound repeated itself. “Okay, now it’s your turn. Call us if you figure it out.”
A space oddity
A recording of this audio and Wilmore’s conversation with Mission Control, It was captured and shared by a Michigan meteorologist named Rob Dale.
It was not immediately clear what was causing the strange and somewhat disturbing noise. As Starliner flies toward the space station, it maintains communications with it via a radio frequency system. However, once docked, there is an umbilical cable that transmits audio.
Astronauts observe such oddities in space from time to time. For example, during China’s first manned space flight in 2003, Astronaut Yang Liwei said He heard a sound resembling that of an iron bucket being struck by a wooden hammer while in orbit. Scientists later realized that the noise was due to small deformations in the spacecraft due to a pressure difference between its inner and outer walls.
The sonar-like noises heard this weekend likely have a benign cause, and Wilmore certainly didn’t sound exhausted. But the strange noises are worth mentioning given the challenges Boeing and NASA have had with Starliner’s first crewed flight, including major in-flight helium leaks and thruster failures. NASA announced a week ago that, because of uncertainty about Starliner’s flight capability, it would return home without its original crew of Wilmore and Suni Williams.
Starliner is planned to return autonomously to Earth Friday, September 6thWilmore and Williams will return to Earth next February, flying aboard A Crew Dragon spacecraft It is scheduled to launch with just two astronauts later this month.
This story originally appeared in Ars Technica.