Rocket launches are so thunderously loud that, even from kilometres away, they can feel like being at the front of the stage at a rock concert. That, plus the fact that launch numbers are booming, has prompted a physicist and biologist to team up to study the effects of noise pollution on wildlife — particularly endangered wildlife — at one of the busiest spaceports in the world.
“You can feel it in your chest — it’s like being in a vehicle that has really big speakers, and you can just feel the vibrations coming through your body,” says one of the researchers, Lucas Hall, a wildlife ecologist at California State University in Bakersfield. Hall remembers watching a launch at California’s Vandenberg Space Force Base from a safe distance. “It’s absolutely nuts.”
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Hall, physical acoustician Kent Gee at Brigham Young University in Provo, Utah, and their team have close to US$1 million in funding from the US Army Corps of Engineers over 3 years to measure the soundscape and monitor a host of endangered and threatened species living near the Vandenberg base. The project, which also includes Darryl York, conservation branch chief at Vandenberg, was presented on 8 May at the Acoustical Society of America annual meeting in Chicago, Illinois. The space base initiated the project, Gee says, because of the threatened species nearby, in the coastal area around Santa Barbara, California. “This is responsible stewardship, in my opinion,” he says.
Vandenberg has, for decades, sent up about 5–15 rockets per year, but with satellite launches from private companies such as SpaceX increasing, the number is set to rise sharply — to 50–100 per year by 2030. That would surpass Vandenburg’s previous record of about 45 launches per year in the mid-1960s, during the heyday of the space race between the United States and the Soviet Union. Last year, there were a record 180 launches worldwide.
“If it’s happening every week, every few days, are there any implications of that?” asks Hall. “That has not been studied.”
This type of study is “incredibly important”, says acoustician Caroline Lubert at James Madison University in Harrisonburg, Virginia, who has worked with Gee but isn’t involved with this project. “It needs to be a priority. We’re only going to have more launches, not less.”
There have long been concerns about the environmental impact of sparked fires, and debris and noise from rocket launches — especially at prominent sites in California, Florida and Texas that are close to US biodiversity hotspots.
SpaceX’s first Starship flight on 20 April unexpectedly blew up the launch pad at the spaceport in Boca Chica, Texas, scattering pulverized concrete and sparking a wildfire in a nature reserve. The incident has triggered a lawsuit from conservation groups, arguing that the Federal Aviation Authority should have subjected the company to a more stringent environmental assessment. The region around the spaceport hosts threatened populations of turtles and birds, including piping plovers (Charadrius melodus), whose numbers are declining, and Northern Aplomado falcons (Falco femoralis), which are endangered in Texas.
Sharon Wilcox, senior Texas representative for the conservation group Defenders of Wildlife, which is based in Washington DC, says the organization has “considerable concerns about the impacts of sound, concussion and vibration resulting from these launches”.
Although it is clear that rocket launches are extraordinarily loud, the details aren’t always predictable or well understood. For instance, Gee measured the noise from last year’s launch of the uncrewed Artemis I mission to the Moon at 127–136 decibels from several kilometres away1. The sound’s intensity was nearly two orders of magnitude greater than predicted by models used in environmental assessments, suggesting a need to revise those models.
It’s not just the volume of the launch noise that’s important for nearby creatures, Gee adds, but also the distribution of sound frequencies. “We have very little information about how animals perceive these sounds,” he says.
Chronic noise pollution — from cities, car or boat traffic, for example — is known to increase stress levels for animals ranging from whales2 to humans. It can also have an impact on birdsong3 and animal behaviour. But the impacts of recurring, extremely loud events such as rocket launches are not well known.
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The team will be measuring the soundscape close to Vandenberg’s many launch sites and, as a control, at locations tens of kilometres away. Animals in these habitats include the western snowy plover (Charadrius alexandrinus nivosus), the California least tern (Sterna antillarum browni), the California red-legged frog (Rana draytonii) and the tidewater goby (Eucyclogobius newberryi). The team has weekly data on plover and tern numbers stretching back to the 1990s, collected by the US Fish and Wildlife Service.
Cameras will capture how animals react to rocket-launch sounds: for example, whether birds abandon their nests or change their foraging or mating behaviour. Audio monitors will pick up whether they alter their songs in response to the noise, in the same way that people yell after loud noise exposure. The birds will have some resilience, Hall says. “But at some point, there’s going to be a threshold where that resilience is overcome.”
Although Hall and Gee have secured funding for only three years, they hope to continue the work for more than a decade.
Space bases already dampen launch noise by dumping massive amounts of water onto the launch pad to absorb sound energy. The study will help to determine whether anything needs to change to protect wildlife, such as avoiding launches during certain sensitive times such as breeding seasons, or changing the shape or size of the fire trench designed to divert rocket fumes, heat and noise. “We have to focus on whether we’re trying to reduce noise, redirect noise or change the frequency of the noise,” Lubert says.