Will I hear the sonic boom?
Which towns hear the boom from the next launch, booster landing or capsule return, how loud, and when.
Upcoming launches
| Town | What you would hear | Peak, psf | When |
|---|
Estimates, good to about a factor of 2. Follow the base's official advisories.
How loud is a sonic boom? Under 0.3 psf a distant thump; 1–3 psf like close thunder.
| Peak | What it is like |
|---|---|
| under 0.3 psf | A distant thump or rumble, like thunder a few miles away. Easy to miss indoors. |
| 0.3 to 1 psf | A clear double boom. Windows may rattle. |
| 1 to 3 psf | Loud, like close thunder. It startles people and pets; car alarms can go off. |
| over 3 psf | Very loud. Rare outside the area right around the landing zone. |
Boom loudness is the peak overpressure on the ground, in pounds per square foot (psf). The US rule proposed for quiet supersonic airliners limits it to 0.11 psf.
Why landings boom on land and launches usually don't A climbing rocket aims its boom out to sea; a falling booster aims it at the ground.
A rocket climbs almost straight up while it is slow. The boom leaves the vehicle on a cone, and only the part of the cone that points down can reach the ground. While the rocket climbs steeper than the cone's angle, nothing points down, so the launch boom starts late, high and far out over the ocean. A booster coming back falls nose-down toward the landing zone at two to four times the speed of sound, so its cone points down all around it and the boom lands on the towns near the base. That is the double or triple boom people hear a few minutes after liftoff.
How the forecast works Forecast weather, traced sound rays, loudness tuned to real booms.
- Atmosphere: NOAA GFS temperature and wind at the site for the forecast hour closest to liftoff, up to about 36 km, with the standard atmosphere above. Launches more than 48 hours away use the standard atmosphere until they come into forecast range; the forecast updates every 6 hours.
- Rays: sound rays are traced from every point of the supersonic flight, in every direction on the boom cone, until they reach the ground or the atmosphere bends them back up. That bending sets the edge of the boom zone.
- Loudness: the standard far-field scaling for a sonic boom (it falls with distance to the power 3/4), calibrated to published measurements of real Falcon 9 and Super Heavy booms, and for capsules to the three ship measurements of Apollo 15's reentry (NASA TN D-6950), which the model matches within 30%.
- Capsule returns: Dragon and Orion now splash down off Southern California and come in from the northwest. The page uses a typical splash point and Apollo 15's speed and height along the way; the capsule is subsonic before its parachutes open.
- Flight path: a typical path for the vehicle (altitude, speed and angle against time), the usual launch direction for the orbit, and the booster's usual approach to the landing zone. Real flights differ.
Limits About a factor of 2 in loudness; not an official advisory.
- The loudness is an estimate, good to about a factor of 2. Hills, buildings and being indoors change what you hear.
- Focus booms (a short, louder boom where the rays bunch up during a turn or slow-down) are not computed.
- Launch times slip. The list comes from Launch Library 2 by The Space Devs.
- This is an independent research tool, not an official advisory. Follow the advisories from Space Launch Delta 45 (Florida), Space Launch Delta 30 (Vandenberg) and Cameron County (Starbase).
Method and code: engine/rocket.py and docs/METHOD.md. Privacy.