How loud is the world's most powerful rocket launch?

The launch of the SLS rocket during NASA's Artemis I lunar mission caused a louder noise than an ambulance siren at a distance of 5 km.

According to new research published in the journal JASA Express Letters , the launch of the Space Launch System (SLS) rocket duo and the Orion spacecraft during NASA's Artemis I lunar mission produced a much louder sound than with predictions, Space on February 18 reported. The noise research team recorded from 5 microphones installed between 1.5 and 5.2 km from Launchpad 39B at Kennedy Space Center, Florida. The noise level at each microphone exceeded the expected level.

Rocket engines produce crackling sounds due to shock waves generated by strong sound pressure thresholds. According to new study co-author Whitney Coyle, the noise level of Artemis I at 5 km is about 40 million times louder than a bowl of Rice Krispies cereal. At this distance, the noise level is 129 dB - louder than an ambulance siren or a chainsaw, enough to damage hearing.

Noise levels above 85 dB can lead to permanent hearing loss with prolonged exposure, according to the US Department of Defense Advanced Hearing Center. The Artemis I launch lasted only a few minutes, and the next SLS launch is at least a year away.

One of the reasons why the launch of Artemis I made such a loud noise was the tremendous thrust of the SLS - the most powerful rocket the world has ever launched. This 98 m high rocket has two solid propellers, combined with the core stage to generate about 4,000 tons of thrust at take-off.

NASA engineers expected the SLS launch to be very noisy, so they poured 1,700,000 liters of water on the launch pad to reduce the sound. However, the SLS is still noisy beyond what NASA predicted in an earlier preliminary assessment. The noise about 5 km from the launch site was nearly 20 dB higher than expected.

"This study is an important step forward, but we are still a long way from understanding everything about how rocket noise is generated, propagated and felt," said physicist Kent Gee at the University of California, Los Angeles. Brigham Young, lead author of the study, said.