The NASA Space Launch System rocket, set for its first flight early Monday, is a giant.
It’s more powerful than rockets launched from the Florida space coast in decades. The orange base stage, surrounded by crisp white solid rocket boosters, helps make it visually unique. Its massive height – 322 feet – also makes it nearly 100 feet longer than other operational vehicles launched from the eastern range.
Upon liftoff, set for 8:33 a.m. EDT, all of these factors and more will be combined to make it one of Florida’s most powerful launches yet. At least 100,000 visitors are expected to congregate in the areas surrounding the Kennedy Space Center for the mission known as Artemis I, which will take the unmanned Orion capsule on a 42-day journey to the moon and back. It will host Pad 39B.
In the event of a delay, there are two backup opportunities – September 2 at 12:48 PM and September 5 at 5:12 PM EST – for SLS.
What would Artemis sound like?
A peek at social media threads suggests that some onlookers expect the SLS to be much higher than the Saturn V, the Apollo-era rocket that took astronauts to the moon.
But in reality, hearing and feeling the power of the SLS – or any missile for that matter – will depend on a range of factors surrounding the viewing locations. Everything from wind to moisture to trees can change what you hear and feel.
“Put this first: it will be loud,” John BlevinsNASA’s chief SLS engineer told FLORIDA TODAY. “No one will be in danger, but it will be as loud as a Saturn V missile.”
But there will be differences, many of which will depend on the location and local weather.
“If you had the same environmental conditions — same location, humidity, wind — the SLS would be higher than both Saturn V and the space shuttle,” Blevins said. “But the decibel level is a very powerful function of where you are.”
The difference in volume is due, at least in part, to the power of the SLS: 8.8 million pounds of thrust more than both the Saturn V and the space shuttle. Other than solid rocket boosters, the SLS actually uses four predecessors RS-25 . shuttle motorsso some similarities are to be expected.
With regard to weather, almost every factor plays a role: humidity, cloud cover, wind direction. Increased humidity, for example, makes sounds louder. Blevins said SLS would be 20% higher on a 90% humidity day versus a 10% humidity day.
“Sound travels faster in moist air than it does in dry air,” Blevins said. “The sound will be louder on a very humid day than it will be on a drier day from the viewer’s point of view.”
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Meanwhile, wind direction plays a role in the direction of sound travel, while clouds can actually help sound travel long distances. The SLS will produce a fair amount of low-frequency rumble thanks to its massive side-mounted solid rocket boosters.
“Let’s just say we have a 1,000-foot cloud surface that goes from here to Tampa,” he said. “They’re going to get a massive rumble in Tampa. The sounds will bounce off this cloud surface. The noise will bounce back and forth and it will continue to spread with the wind.”
But one of the lesser known influences, at least from a general perspective, is vegetation.
“After I finished my PhD, I did a lot of consulting in aerodynamics and acoustics. We were testing (the Air Force) F-22 . jet engine In the 1990s, neighbors complained because these were many hours of testing,” Blevins said. So we literally planted 1,000 acres of 6-foot-tall pines and cut out all the noise. The vegetation is a huge damper.”
While these factors will affect the experience, there is no other way to explain it to the locals: SLS won’t be shy. Its highest point, at least when measured by cushion instruments, will occur immediately after liftoff from plate 39B when the rocket’s thrust interacts with the cushion infrastructure.
Because of the variety of factors involved, it is difficult to determine what decibel level spectators can expect. But those watching from popular sites in or near KSC will likely encounter sounds north of 100 decibels – the equivalent of a jackhammer.
Blevins knows the rumble will make him and his team into KSC’s Launch Control Center Proud of their work. But he hopes it will inspire others, too.
“It helps all of our industries. It helps our industrial base. People will see these launches and may end up designing planes and cars, which I accidentally used to do decades ago. It will inspire them to go into engineering and do great things with their hands, their knowledge and their technology.”
What will your Artemis look like?
Florida is often the subject of jokes due to its lack of hills, but that can be an advantage for viewers. Once the SLS has cleared lines of trees and buildings, most people in town to see the launch should have some stunning views.
That doesn’t mean the outer towers won’t be able to see them either since some daytime launches can be seen 150 miles around KSC, including areas like Tampa, Orlando and Jacksonville. Since Monday’s track takes the SLS northeast, people in areas like Miami hoping to see it may be able to spot a bright spot at best.
The SLS’s size compared to other operational missiles will help make it more visible once it’s in the air:
- SLS: 322 feet, 8.8 million pounds of thrust
- 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: Depending on configuration, 188 to 215 feet and 860,000 pounds to 2.7 million pounds of thrust
But seeing the missile after takeoff and separating the massive solid rocket boosters — set for T-plus 2 minutes 12 seconds while the missile travels 3,170 miles per hour — likely drops to local drag cover. If cloudy conditions are expected near the viewing sites, this could easily obscure most of the launch although it will still be audible.
Mark Arcambault, A Co-professor From space science, physics, and space science at Florida Tech, agreed with Blevins: Everything depends on location and local conditions. He expects to see the SLS from the university’s main campus in Melbourne, which is about 38 miles from the plate in a straight line.
“Wind for certain weather conditions in general, cloud cover and humidity, and what is between you and the rocket” will make a difference, Archambault said. “This is a very big problem. Those of us in the industry are particularly interested, but for those who also live here and casually pursue these things, it is still a huge problem.”
Monday 29th August launch
- Rocket: NASA’s Space Launch System
- Mission: Artemis I
- Launch time: 8:33 a.m. EST
- Launch window: 2 hours
- Launchpad: 39B at the Kennedy Space Center
- Route: Northeast
- Duration: 42 days
- Windows Backup Runs: September 2 at 12:48 PM and September 5 at 5:12 PM EST
visit floridatoday.com/space 5 a.m. Monday, August 29, for real-time updates and live video.
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