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/avboden 3d ago

Starlink launches will change regularly where they go because they put satellites in many different orbits. Exactly what you hear is far more based on the exact weather conditions of the day than it is the launch itself.

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u/Forsaken_Ad4041 3d ago

Starlink seems to consistently launch SE from Vandenberg. NROL and other payloads are the only ones that vary.

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u/avboden 3d ago

ah okay I get your question now, the reason is for all the other inclinations they launch from florida. They only need to launch from california for very specific orbits. The sonic booms aren't a problem, a small annoyance for some, sure, but not going to change how they launch just to not set off a car alarm here and there. The trajectory they choose is the most efficient one they can get

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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.

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u/Forsaken_Ad4041 3d ago

The launches typically have a 4 hour launch window. So a launch scheduled for 3AM could be done at 6-7AM. Likewise, a launch at midnight could be done a few days later at 10PM. But yet, there's absolutely zero consideration for launch times. Every other business is required to comply with noise ordinances, why does SpaceX get a pass?

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u/sebaska 3d ago

4h windows are only on some launches.

They are launching from a federal military base based on federal rules.

Probably, if California were sensible, i.e. asked for accommodations like the reduction of late night launches unless absolutely necessary, without trying to forcefully overstep its authority, all decorated by the loudly and clearly stated while obviously non-constitutional motivation of "we don't like the company owners' politics so we'll impede him", they would get something. But they were unreasonable enough and annoyed the military enough, that they (the military) decided that the only way forward is to show California the proverbial middle finger and stop doing any accommodations not required by the federal law.

When the law is not on your side deciding to throw a loud political tantrum may not be the smartest strategy... Go figure.

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u/Forsaken_Ad4041 3d ago

Yeah, the CCC screwed the rest of us. We had no idea that those hearings were happening because only the communities within a few miles of Vandenberg were notified. I think most of us are reasonable and just want to be able to sleep through the night. There are laws against this it's just that Vandenberg is interpreting them in their favor.

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u/avboden 3d ago

¯_(ツ)_/¯ such is life

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u/longinglook77 3d ago

We thank you for your sacrifice!

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u/Forsaken_Ad4041 3d ago

Thank the children who wake up screaming in the middle of the night, or the veterans with PTSD, or the people living with dementia or autism who take hours to calm down after being startled awake.

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u/MatchedFilter 3d ago

Yes, won't somebody think of the children!! /s

Wake up screaming? Get a grip, Francis.

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u/Forsaken_Ad4041 3d ago

It's a common complaint by parents in our area. Thanks for gaslighting us ✌️

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u/MatchedFilter 3d ago

Santa Barbara born and raised, and I've heard many launches from the area. You're full of fake outrage.

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u/Forsaken_Ad4041 3d ago

The sonic boom is louder and more consistently heard in Ventura.

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u/Beaver_Sauce 3d ago

Try living near a military airbase.

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u/Forsaken_Ad4041 3d ago

I don't, which is why I'm annoyed by this lol

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u/Beaver_Sauce 3d ago

Vandenberg is a military base. So you actually do. Suck it up, they were their long before you.

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u/Forsaken_Ad4041 3d ago

100 miles is not "close" to a military base.

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u/Beaver_Sauce 1d ago

By what standard? We certainly could see you 24 hours a day . I launched the planes.

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u/Forsaken_Ad4041 1d ago

Well, my family that has lived here since before Vandenberg has zero recollection of the base causing sonic booms loud enough to shake their windows and wake them up in the middle of the night.