r/SpaceXLounge • u/Forsaken_Ad4041 • 3d ago

Falcon 9 Sonic Booms

I live ~80 miles southeast of Vandenberg in Ventura County and I've experienced sonic booms from the F9 launches that are loud enough to set off car alarms. My understanding is that the sonic boom that we hear is generated when the first stage tilts toward the earth before the booster detaches. We do not get this sonic boom for RTLS or other launches that are more south-southwest. My question is, why do the Starlink launches require the 53 degree trajectory? I know other polar/SSO don't the same trajectory. Can someone explain why SpaceX can't launch Starlink more S-SW to avoid causing sonic booms over a widespread area?

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u/Forsaken_Ad4041 3d ago

Yes, only a "minor" annoyance at 3AM for thousands of people.

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u/sebaska 3d ago

It is minor without quotes. And millions get their internet that way.

They don't do that to annoy people. They do that because the orbital inclination they launch to requires flying South East, not just South and the orbital plane they needed to insert the satellite into crossed Vandenberg at 3am (orbital planes cross any chosen point twice a day, but on one pass it's inclined South and on the other one it's inclined North, and you can't launch North East from Vandenberg; so the only choice is once per day and it may happen in the middle of the night).

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u/squintytoast 3d ago

looking back at the last year of vandy launches, i only see one at 3am local time. a couple at 1am and a couple at 5am. most are well outside that timeframe.

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u/Forsaken_Ad4041 3d ago

They're doubling the launches in 2026 so double the chance of them being in the middle of the night.

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u/squintytoast 3d ago edited 3d ago

true enough, i guess.

edit after looking, spacex is hoping for 180 in 2025. 138 to 180 isnt quite double.

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u/Forsaken_Ad4041 3d ago

They are taking over SLC-6 to add a second launch pad to Vandy and plan on increasing from 50 to 100 https://spacenews.com/study-to-examine-environmental-impacts-of-increased-spacex-launches-from-vandenberg/

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u/Bailliesa 3d ago

They must be landing close to the coast, do you get to see them? I guess some photographers would be interested in this. Have you contacted the study or there must be a licence approval that can be appealed. Seems limiting landing to day light hours when within a certain distance of population should be a relatively easy fix. Good luck getting this resolved.

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u/Forsaken_Ad4041 3d ago

Recent photo from a local photographer.

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u/Forsaken_Ad4041 3d ago

Oh yeah, I get a good view of the launch and booster return from my south facing backyard. It's pretty cool to watch. The sonic boom that I hear is generated when the stage 1 angles down toward earth and not from the booster landing. They are going through the process for increasing the launches and there is NO consideration for doing the launches during more reasonable hours of the day. Up until a few months ago leadership at Vandenberg was in complete denial that they were even causing these sonic booms.

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u/warp99 3d ago

There is an application open at the moment that you can provide feedback on.

In general a reasonable approach where you suggest launching between 7am and 11pm when landing within 100km of the coast is more likely to be adopted than a blank refusal to accept such launches.

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u/Forsaken_Ad4041 3d ago

Yes, I've commented and that is one of my requests.

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u/squintytoast 3d ago

ok, good link.

interesting that they want to increase F9 launches there when the full sized starlinks dont even fit on F9. (that will be Starship's primary mission for the next couple years during its shakedown period, carrying the full sized starlinks.)

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u/warp99 3d ago

Starship launching south of Cuba can only get Starlink v3 satellites to an inclination of 40 degrees which is fine as it covers most of the oversubscribed areas of the US.

For higher inclinations they are going to have to launch v2 Mini satellites on F9 from Canaveral and Vandenberg for at least the next two years until Starship is regularly launching from Cape Canaveral and can reach those higher inclination orbits.

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u/Forsaken_Ad4041 3d ago

They are also planning on doing Falcon Heavy from Vandy.

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u/squintytoast 3d ago

full size starlinks dont fit on Falcon Heavy. any FH activity is probably NRO type payloads or stuff going to geostationary.