Fact check: Saturn V was as loud as 10,000 jet engines, but it didn't melt concrete

NASA's Space Launch System (SLS), which is scheduled to launch on Monday, August 29, is the U.S. space agency's most powerful rocket to date.

I will produce 9.5 million lbs (4309 tonnes) of thrust and carry a payload capacity of 190,000 lbs (86 tonnes) up to low-Earth orbit (LEO). By comparison, NASA's Saturn V rocket used for the Apollo missions produced 7.5 million lbs of thrust.

Saturn V obviously isn't any slouch. The historic rocket is, at the time of writing, the most powerful rocket to successfully launch to orbit — though it will soon likely be overtaken by SLS and SpaceX's Starship.

A common Saturn V misconception

Though Saturn V was an incredibly powerful rocket in its own right, a few misconceptions have spread online regarding the launch vehicle in recent months and years.

According to a report from SciTech Daily, one widely-spread internet claim is that Saturn V's acoustic power melted concrete and lit grass on fire over a mile away from the rocket pad — Spinal Tap would surely be impressed.

Scientists from Brigham Young University (BYU) disproved these false claims, and they laid out their methods in a new paper published in The Journal of the Acoustical Society of America. They used a physics-based model to estimate the acoustic levels of the Saturn V rocket at a value of 203 decibels, which matches the limited sound data from the 1960s.

"Decibels are logarithmic, so every 10 decibels is an order of magnitude increase," said author Kent L. Gee, of BYU. "One hundred and seventy decibels would be equivalent to 10 aircraft engines. Two hundred would be 10,000 engines!"

Saturn V took on a 'legendary, apocryphal status'

Though Saturn V was incredibly loud, the researchers behind the new paper said its acoustic power was nowhere near enough to start grass fires, let alone melt concrete. If reports about grass fires starting a mile away from launch are true, they were likely caused by radiative heating or debris.

"The Saturn V has taken on this sort of legendary, apocryphal status," said Gee. "We felt that, as part of the JASA special issue on Education in Acoustics, it was an opportunity to correct misinformation about this vehicle."

Some of the confusion regarding the sound power of Saturn V stems from misunderstanding the difference between sound power and sound pressure, the researchers explained. The former is like the wattage of a light bulb, while the latter is like its brightness. Now that they've helped to dispel a widely spread misconception, the team from Brigham Young University (BYU) plans to take precise acoustical measurements at the launch of SLS so that such questions about its acoustic power won't be up for debate — at least not to the extent at which they were for Saturn V.