Welcome to the Vandenberg Space Force Base FAQ page. We've compiled these frequently asked questions to help our local residents understand the sights, sounds, and vibrations associated with the rocket launches from VSFB Space Launch Complexes (SLCs) and the booster landings that may accompany them.
A sonic boom is a thunder-like noise a person on the ground hears when an object or vehicle—like a rocket booster—travels through the air faster than the speed of sound. This creates shock waves that travel outward and downward toward the ground.
We actively prioritize scheduling launches during normal daytime waking hours. Nighttime launches are generally avoided unless they are essential for national interests and our acoustic noise models predict that no sonic boom will be heard onshore.
After launching its payload into space, the first stage (booster) of the rocket separates and descends through the atmosphere to land either on a droneship or at a landing pad here at Vandenberg. Because the booster is falling back to Earth at supersonic speeds (faster than the speed of sound), it produces a sonic boom.
While most supersonic aircraft produce a standard "N-wave" (a two-shock sonic boom: one from the nose and one from the tail), the Falcon 9 booster has a unique shape that produces a three-part sonic boom. Recent research shows that this extra middle shockwave is caused by the booster's specific aerodynamic features during its descent. Specifically:
First shock: Comes from the base of the rocket (the engine section, which is leading the fall).
Second (middle) shock: Caused by the booster's extended grid fins (near the top) combining with a shockwave produced by the folded landing legs (near the bottom).
Third shock: Comes from the top of the booster as the air returns to its normal ambient pressure.
The intensity of the sonic boom depends on how far you are from the landing location and current weather conditions:
Close to the landing pad (within 2 km / 1.2 miles): The boom can produce peak overpressures of 6 to 10 pounds per square foot (psf), which is quite loud and will be felt strongly.
Further away (around 10 km / 6.2 miles): The pressure drops to about 2 to 3 psf.
Far distances (up to 25 km / 15.5 miles or more): The triple sonic boom can still be clearly measured and heard, though it will sound more like a distant, deep rumble or thump.
While the boom can be loud and the resulting vibration may rattle windows, doors, and walls (similar to a close crack of thunder), the overpressures generated in civilian areas are typically well below the threshold that causes structural damage.
The perceived loudness of a sonic boom is heavily influenced by atmospheric conditions at the time of the flyback. Factors such as:
Wind direction and speed
Cloud cover
Humidity
Temperature gradients
These elements can either dissipate the sound or focus/bend the shockwaves toward specific areas on the ground, making the same rocket sound significantly louder or softer from one launch to the next. The specific trajectory of the rocket also dictates which communities will be in the boom's path.
No. The triple sonic boom is entirely caused by the booster's physical geometry (its shape, grid fins, and landing legs) rapidly displacing air as it falls. The booster's engines are usually off during the majority of the time the sonic boom is generated, only turning on at the very end of the descent for the final subsonic landing burn.
Yes, this phenomenon is not isolated to a specific rocket.
Your peace and safety are foundational to our mission. We actively work to mitigate noise impacts through:
The ECOBOOM Program: We have partnered with academic institutions like BYU and CSUB to collect and analyze extensive acoustic data on our launches.
Data-Driven Planning: Before every launch, we use sophisticated acoustic models to forecast the potential impact of sonic booms. We analyze this data both pre- and post-launch to continuously refine flight paths and minimize community disturbance.
Vandenberg is committed to being a good neighbor. We partner with local municipalities, chambers of commerce, and organizations like the Santa Barbara County Association of Governments (SBCAG) and Caltrans to address housing, transportation, and quality-of-life services. Furthermore, through programs like Space Vandenberg, we are investing in local STEM education, internships, and critical infrastructure to support our shared community.
If you have further questions or concerns regarding launch activities, please contact the Vandenberg Space Force Base Public Affairs Office.