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We rarely have time to write about all the cool science stories that come our way. , is doing a special 12 Days of Christmas series of posts. The V projectile was loud enough to melt concrete.
The 1967 Apollo 4 mission was an unmanned flight to test the Saturn V rocket as a viable rocket for future manned missions. The experiment was a huge success and marked an important step in the US space program. But the Saturn V was so incredibly loud that rumors spread that its sonic energy was enough to melt concrete. Not so, according to an August paper published in the Special Education Issue of the Journal of the Acoustic Society of America (JASA).
“Saturn V has achieved this sort of legendary apocryphal status,” says co-author Kenneth Gee of Brigham Young University. “As part of his JASA Special Issue on Acoustic Education, I felt it was an opportunity to correct some misinformation about this vehicle.” It contains some issues to be resolved. This includes the ironic problem of using acoustic temperature to make a grilled cheese sandwich.
German rocket scientist Wernher von Braun, who helped build the V-2 rocket, joined NASA in 1945 as part of Operation Paperclip. His job was to share his accumulated knowledge with the Army’s Rocket Division. But when the Soviets launched his 1957 Sputnik 1, priorities changed and von Braun’s team was tasked with developing an equivalent US-made rocket. Juno 1 launched his first US satellite in January 1958 and was used as a prototype for the Saturn series to be deployed on Earth orbit and lunar orbit missions.
The Apollo 4 mission launched on November 9, 1967 at 7:00 AM EST on a Saturn V. When five of his F-1 engines ignited eight seconds before takeoff, the sound pressure produced was so powerful that the launch pad was more than three miles (5 km) away. Instead, waves hit the vehicle assembly building, the launch control center, and the press building. over there. CBS reporter Walter Cronkite and his producer had to hold onto the trailer’s observation window when the ceiling tiles fell to the floor, fearing they would shatter from the noise. Cronkite later claimed it was the scariest space mission he had covered.
“It’s like a constant thunderclap, and when I think it can’t get any louder, it does. I remember it felt like a vibration going through my bones… Birds rising, flames erupts, followed by a thunderclap, which rises and finally fades into the sound of a billion thick sheets of paper being torn vertically for a minute.”
The memorable was sure to inspire some exaggerated claims and unsubstantiated rumors over the decades that followed. othersWe conducted a review of online forums and discussion boards and were disappointed with the amount of misinformation spread on them. In addition to claiming that the noise level was sufficient to melt concrete, it also claimed that “grass was burning more than a mile away,” “set bystanders’ hair on fire,” and “rainbows from the sky.” According to the authors, “Such a claim awes the power of the vehicle that propelled mankind to the moon, but nevertheless, it is a truism about the true acoustic environment.” It is based on an erroneous understanding.”
Its acoustic environment analysis incorporates NASA footage of the Apollo 17 launch digitized by the Discovery Channel for the 2008 documentary. Their physics-based model fixed the sound level at 203 decibels. According to Gee, 170 dB is equivalent to 10 aircraft engines and 200 dB is equivalent to 10,000 aircraft engines.
Considering the human pain threshold is around 130 dB, this is pretty loud. It wasn’t loud enough to melt concrete or set grass on fire.Gee othersThis myth is believed to have evolved from the confusion between sound power (which corresponds to the wattage of a light bulb) and sound pressure (which resembles the brightness of a light bulb). If you see reports of burning grass or melting concrete, it’s more likely to be caused by radiant heating from a plume or debris, rather than the sound of the Saturn V.
DOI: Journal of the Acoustical Society of America, 2022. 10.1121/10.0013216 (About DOI).
