The five videos begin with the familiar sight of dozens of harbor seals splayed peacefully on the beach of their Carpinteria rookery. Suddenly, in unison, the colony members raise their heads and look north as the low rumble of a SpaceX rocket launched from Vandenberg Space Force Base culminates in a sonic boom. Startled, the seals rush, or “flush,” into the ocean. In one instance, blood pools in the surf among the mass of frantic bodies.
“Stress from such disturbances can lead to miscarriage or premature birth,” stated Becki Norton with Carpinteria Seal Watch (CSW), a citizen group that monitors the protected rookery, one of only four in Southern California. The five video clips were captured between January and May during peak pupping season. “Chronic disturbance can also lead to long-term behavioral changes, such as abandonment of haul-out sites and declining reproductive success,” Norton said, noting overall colony numbers have declined in recent years.
Norton’s comments are among those being submitted to Vandenberg as the base attempts to increase the frequency of its rocket launches threefold, from approximately 30 a year to more than 100. A draft environmental report that assesses the federal project’s potential impacts to air quality, noise, wildlife, water, and other local resources was released last week, with a public feedback period open until July 7. Written comments can be submitted at vsfbfalconlauncheis.com, and a virtual public hearing is scheduled for June 18, 6-8 p.m.
With respect to effects of steady sonic booms on seals and other pinnipeds, the draft report acknowledges that marine mammals “would be disrupted by noise and visual disturbance” associated with launches and landings. But it states any behavioral changes would be temporary and not exceed the threshold of “Level B harassment.” “The wording appears to be minimizing/downplaying the impacts on the seals, and in my opinion, this needs to be challenged,” said Norton.
Meanwhile, Vandenberg is partnering with Brigham Young University and Cal State Bakersfield on a sonic boom study to better understand the intricacies of the acoustic events that rattle windows and nerves up and down the coast. The research team has so far installed 25 monitoring stations across 500 square miles of California ― from the beaches of Isla Vista to the hills of Ojai ― that are capturing data on the highly complex noise patterns created by rockets, given their unique flight paths, rapid acceleration, and extreme altitude changes.
“It’s like trying to catch lightning in a bottle,” said Kent Gee, chair of the Department of Physics and Astronomy at BYU. “All launches generate sonic booms; however, their audibility to the public is influenced by several factors, including the launch trajectory, the size of the rocket, and atmospheric conditions.”
Central California’s microclimates add yet another layer of complexity to the research. “We are in the process of understanding these microclimates and creating a three-dimensional map of sound to understand how launches impact different areas,” Gee said. “The data we have collected is already yielding surprises.”
Col. Mark Shoemaker, who oversees the Vandenberg spaceport and test range, said the base is committed to supporting national defense while also addressing concerns like launch noise and impacts to the region’s fragile ecosystems.
“It’s a delicate balance,” Shoemaker said. “Every adjustment we make has ripple effects. Fly too far west, and it could compromise our ability to get satellites into the required orbit. Fly too far east, and there might be increased noise in populated areas. But we’re committed to collecting data, following the science, and optimizing operations.”
Also this week, U.S. Representative Salud Carbajal introduced the Space Launch Noise Mitigation Study Act, legislation that would support a grant program for affected communities to install new “noise-mitigating technologies.” Last December, Carbajal secured language in a federal defense bill that — for the first time — acknowledged the impacts of sonic booms on nearby populations.
