Researchers at Brigham Young University found that one Starship launch produces loud noises that could damage nearby homes.
South Texans have spoken out for months about how powerful the noise of SpaceX's Starship is, comparing it to an earthquake. Now, a study proves that the sound of Starship's launch and booster landing is uniquely disruptive, despite SpaceX likening it to thunder.
Comparing Starship's acoustics to other powerful rockets, researchers at Brigham Young University found that one Starship launch produces the noise equivalent of four to six launches of NASA's Space Launch System or at least 10 Falcon 9 launches. Starship has launched exclusively out of Texas so far and is expected to take flight from Boca Chica for a sixth time Tuesday afternoon.
The findings, which were published in the Journal of the Acoustical Society of America on Friday, used noise measurements to determine that the impact of Starship can be felt from miles away. The impact is especially present in Texas' Port Isabel and South Padre Island's south end, which see a greater risk of structural damage, such as glass breaking or small items falling.
Physics professor Kent Gee, who led the study with a team at BYU's Physics and Aerospace Student-Centered Acoustics Laboratory, said Starship has "this low-frequency rumble that's just overwhelming."
"And then on top of it, you have this kind of high-frequency popping. I call it crackle," Gee said in a news release. "It's a very unique sound experience."
The research team collected data during Starship's fifth flight test in October at eight sites including the Margaritaville Hotel roof in South Padre Island, national wildlife refuge areas and close to spectators viewing the launch.
Ultimately, researchers measured decibels at a maximum of 105 in the town of Port Isabel about 6 miles from the launch site, which is similar to a rock concert or chainsaw levels. Even in Brownsville, which is further away from the launch site, the maximum levels are equivalent to a hair dryer or vacuum cleaner.
The loudest part of the launch occurred during SpaceX's new trick of returning the rocket's first stage booster to the launch site, reaching about 125 decibels in Port Isabel and South Padre Island. Researchers compared that sound to a gunshot recorded at 2 feet or like a firework at 500 feet.
Gee noted that with Starship launches projected to happen 100 times annually, the noise could bring implications such as window rattling, sleep disruptions, alarms setting off and disruptions to wildlife populations. During their data collection, the team noticed other disturbances including car alarms going off and dogs barking over the noise.
Still, researchers noted that more data should be collected and additional measurements are needed to understand Starship's potential noise impacts on sensitive structures, communities and the environment.
The October launch that BYU researchers studied happened after the Federal Aviation Administration suggested a later launch date, saying more time was needed to look into the impact of sonic booms. Concern mounted that it could affect local wildlife, and the agency wished to consult with the U.S. Fish and Wildlife Service.
But SpaceX pushed ahead anyway on an earlier launch, in an event that almost resulted in the rocket crashing into the ground.
SpaceX and its activities have previously affected Texans' homes. South Texans near Boca Chica's launch site have bemoaned the noise, calling it "terrifying." Earlier this year, a Waco man sued the company, saying nearby rocket engine testing at the company's McGregor facility damaged his house's foundation. Before that, a family living 10 miles from the facility said a sonic boom shattered a glass door at their home.
For Tuesday's flight test, the research team at BYU plans to collect more data. In all, they transported three pallets of equipment, including computers, data acquisition systems, GPS, microphones and windscreens.
"We are a space-going people now, and it's a delicate balance," Gee said. "How do you balance that with making sure you're being a good environmental steward? Our research will see what the impacts are on threatened or endangered species in the region, as well as the impact on community life."