US astronaut Barry Wilmore called NASA ground crew on Saturday, asking for help with a repetitive knocking sound that was coming from the Boeing Starliner craft. The interaction was captured by a NASA Space Flight forum member, who included a recording of it in a post that was spotted by Ars Technica.

In the recording, Wilmore asks NASA crew in Houston to configure their call so that he could show them the noise, which he says is coming from the speaker inside Starliner. Then, a repetitive…