It will be loud, but it depends on how loud it is

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NASA’s Space Launch System rocket, which made its maiden flight Monday morning, is a behemoth.

It’s more powerful than the rockets launched from Florida’s Space Coast in decades. An orange main stage surrounded by bright white solid rocket boosters helps make it visually unique. And its impressive height—322 feet—makes it nearly 100 feet taller than other operational vehicles launched on the East Range.

All of these factors and more will combine to make it one of Florida’s most powerful, thunderous launches to date during its takeoff, set for 8:33 a.m. EDT Monday. At least 100,000 visitors are expected to flock to the grounds surrounding Kennedy Space Center. Artemis I, will carry the uncrewed Orion capsule on a 42-day flight to the moon and back. Pad 39B will host.

In case of delay, two backup possibilities – September. 2 hours 12:48 and September. 5 at 5:12 pm EDT – Available for SLS.

What will Artemis I sound like?

A look at social media threads shows that some viewers expect the SLS to be significantly higher than the Saturn V, the Apollo-era rocket that carried astronauts to the moon.

But in reality, hearing and feeling the power of the SLS — or any rocket for that matter — will depend on many factors including the review sites. Everything from winds to humidity to trees can change what you hear and feel.

“Put it down first: it’ll be loud” John Blevins, NASA’s chief SLS engineer, told FLORIDA TODAY. “No one will be in danger, but it will be as loud as a Saturn V rocket.”

But there will be variations, many of which will depend on location and local weather.

“If you have the same environmental conditions — the same terrain, humidity and wind — the SLS will be higher than both the Saturn V and the space shuttle,” Blevins said. “But the decibel level is an extremely strong function of where you are.”

The difference in volume is due, at least in part, to the SLS’s thrust: 8.8 million pounds is more than both the Saturn V and the Space Shuttle. Aside from solid rocket boosters, the SLS actually uses the previous four RS-25 shuttle enginesso some similarities are to be expected.

In terms of weather, almost every factor plays a role: humidity, cloud cover, wind direction. More humidity, for example, makes sounds louder. SLS will be about 20% higher on a 90% humidity day compared to a 10% humidity day, Blevins said.

“Sound travels faster in humid air than it does in dry air. On a very humid day, it’s going to be louder from an audience perspective than it is on a drier day,” Blevins said.

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More:NASA is preparing to send the giant SLS rocket to the Moon for the Artemis I mission

Wind direction plays a role in the direction sound travels, and clouds can actually help sound travel long distances. The SLS will produce a fairly low-frequency rumble thanks to its massive side-mounted rocket boosters.

“Let’s say we have a 1,000-foot cloud deck that extends from here to Tampa,” he said. “They’d get a big rumble in Tampa. The sounds would bounce off the cloud deck. The sound would just bounce back and forth and keep going with the wind.”

But one of the lesser-known impacts, at least from a public perspective, is vegetation.

“After completing my PhD, I did a lot of consulting on aerodynamics and acoustics. We (Air Force) F-22 jet engine In the 1990s, and the neighbors complained because it was a long hours of testing,” Blevins said. “So we literally planted 1,000 acres of 6-foot tall pine trees and it dampened all the noise. Vegetation is a big damper.”

Although these factors will affect the experience, there’s no other way for locals to explain it: SLS won’t be shy. Its loudest sound, at least as measured by pad instruments, will occur shortly after liftoff from Platform 39B, when the rocket’s thrust interacts with the pad infrastructure.

Due to various factors, it is difficult to say what decibel level the audience can expect. But those watching from popular sites at or near KSC will likely experience sounds north of 100 decibels—the equivalent of a hammer.

Blevins knows the buzz will make him and his team at KSC Start Control Center they are proud of their work. But he hopes it inspires others.

“It helps all of our industries. It helps our industrial base. People will see these releases, and as a result they can design airplanes and cars that I accidentally did decades ago. It will inspire them to go into engineering and do great things with their hands, science and technology,” he said.

What will my launched Artemis look like?

Florida can often make jokes about its lack of hills, but that can be an advantage for viewers. Once the SLS clears the tree lines and buildings, most people in the city should have spectacular views to witness the launch.

That doesn’t mean out-of-towners can’t see it, though, as some daytime releases are visible within a 150-mile radius around KSC, including areas like Tampa, Orlando and Jacksonville. As Monday’s trajectory heads northeast of the SLS, people in areas like Miami hope it will produce a bright spot at best.

The SLS’s size compared to other operational rockets will help it make another appearance in the air:

SLS: 322 feet, 8.8 million pounds of loss
SpaceX Falcon 9 and Falcon Heavy: 230 feet, 1.7 million pounds, and 5.1 million pounds of thrust, respectively
United Launch Alliance Atlas V: 188 by 215 feet and 860,000 to 2.7 million pounds, depending on configuration

But seeing the rocket’s large solid rocket boosters separate after takeoff and separation — T-plus is designed for 2 minutes and 12 seconds as the rocket travels at 3,170 mph — will likely fall into local cloud cover. If cloudy conditions are expected near the viewing locations, this can easily obscure most of the launch process, although it is still loud.

Mark Archambault, and Docent Blevins, an aerospace, physics and space sciences major at Florida Tech, agreed: it will all depend on the location and local conditions. He expects to see SLS from the university’s main campus in Melbourne, about 38 miles from the pad in a straight line.

“Certain winds, atmospheric conditions in general, cloud cover and humidity and what’s between you and the rocket are all going to make a difference,” Archambault said. “That’s a huge thing. Those in the industry are especially interested, but for those who live around here and happen to watch these things, it’s still a big deal.

contact us Emre Kelly hour aekelly@floridatoday.com or 321-242-3715. Follow him Twitter, Facebook and Instagram On @EmreKelly.

Monday, August. 29