Even from afar, the rocket is louder than a jackhammer

Rocket launches are among the loudest audible noises in the world. A research team has now examined the volume of the most powerful rocket launched to date: The launch of the launch vehicle "SLS" during the moon mission "Artemis 1" in mid-November last year generated 136 decibels at a distance of 1.5 kilometers, which is about the launch of a equivalent to jet aircraft.

Even at a distance of 5.2 kilometers from the launch pad, 129 decibels were still measured, more than a chainsaw or jackhammer typically produces, as the scientists from Brigham Young University (BYU) and Rollins College report in the journal "JASA Express Letters". The value was almost 20 decibels higher than that predicted in a noise model. "This suggests that the models need to be reviewed and likely revised," said co-author Grant Hart of BYU.

The research team had taken noise measurements at various locations around the Kennedy Space Center during the launch. The study is intended to help investigate the impact of rocket launches on the environment. It was initially unclear how loud it was directly at the launch pad. According to an earlier analysis by Brigham Young University, the launch of a Saturn V rocket once reached about 203 to 204 decibels at the ramp. In mid-November, the "Space Launch System" (SLS) had 13 percent more thrust than a "Saturn V" ever had, according to a statement on the current analysis.

There are many myths surrounding the "Saturn V" launches. There are erroneous reports of molten concrete and distant grass fires as a result of the immense noise. If there were such incidents, they were more likely due to the radiant heat of the exhaust plume.

Around 125 decibels is considered the limit above which people suffer physical pain. The perception of loudness is not linear: According to experts, ten decibels more feels about twice as loud for one person than for the other.

The "Artemis" program consists of several missions. The first - "Artemis 1" - has already been largely successfully completed. On December 11, 2022, the unmanned capsule of the spacecraft "Orion" landed in the Pacific after orbiting the moon. The launch vehicle "SLS" has four liquid hydrogen-oxygen main engines and two solid boosters. According to the researchers, the latter are probably the main source of the noise level of the start.

Many of the loudest sounds ever come from bombs releasing extreme energy. Perhaps the loudest sound ever recorded may have been the Krakatoa volcano erupting in 1883. At the time, the explosion could be heard 3,000 kilometers away in Perth on Australia's west coast. It largely destroyed the mountain and its island and triggered a tsunami that killed at least 36,000 people. According to NASA, a volume of 180 decibels was still measured at a distance of 160 kilometers. Therefore, it is estimated that the value on site was over 300 decibels.

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