Hacker News Reader

Comment by rolph | Hacker News Reader

you are quite wrong about that, and im sure it wasnt "in space".

i live in a place between two major installations, and see uncommon things often. [such as X-45 variants https://en.wikipedia.org/wiki/Boeing_X-45]

this happened a little before 2:00 hours saturday morning, and was the loudest thing ive ever heard and felt in my life, and was definately not an earthquake, or a hurricane, i saw the spiral.

View on HN

https://earthquake.alaska.edu/event/0234u0lcjp

https://earthquake.alaska.edu/event/0234u01ap5

Would it have been around this time? I'd be interested to know if their seismographs can be used to detect non-earthquake recordings.

When I was little I lived less than an hour from Cape Canaveral and damn, when those shuttle missions launched, you'd feel it in your bones. I'm not sure how it would feel if it were just in the air crossing my path though.

2nd link would be the closest but not, the right time. there was definately acoustic energy, in the air, this wasnt ground tremor, it was distinctly different, and the volume followed the appearance, zenith, and dissapearance of the spiral.

it was not a snowquake either, and it wasnt from Clear, or Elmo.

I'm sorry, but you're definitely misattributing this. The rocket in question was launched from Vandenburg SFB in California. It was not close enough to you by the time it reached Alaska to have knocked anything off a shelf.

so it didnt fly over central matsu valley, denali range and delta junction?

https://www.theguardian.com/us-news/2023/apr/18/northern-lig...

perhaps you could enlighten me with a trajectory during launch, and during stage recovery. im not the only one that saw the spiral, and i had nieghbours on the next ridge that were disturbed by it as well, they thought the noise was my fuel exploding.

No, it definitely did fly over you. I apologize that I was unclear in my earlier comment. I meant to say "It was not close enough to you by the time it was over Alaska" since it was a polar launch (Northward)

I'm not telling you that you didn't see the spiral, I'm telling you that there's no physical way that it could have knocked anything off your shelf from the upper atmosphere.

so 50-60 miles is recognized as the edge of space, is that too far for a shockwave to travel?

im looking at the idea this was re-entry shock from an jettisoned booster stage, either that or there was someonelse , using the spaceX as cover for thier own launch, but i havnt heard about anything from Kodiak.

It's difficult to say what precise altitude it was at, but the spiral formation is from the final booster stage jettisoning fuel so that it doesn't explode on re-entry. That means, in very broad terms, the spacecraft and the booster were likely in the low earth orbit regime, and likely just under orbital velocity for the spacecraft.

Given that the spiral had a northward azimuth from Delta Junction (as per the article) the draining happened after it had already passed overhead, and it was likely very far away when it actually re-entered. At an inclination in line with Vandenburg, it likely landed in the Pacific.

I am an astrodynamicist but my work in launch dynamics is a bit rusty, so bear with me if my off-the-cuff estimates are off.

that seems to describe the path, the [sound] intensity was in sync with the path of the spiral.

It was in space though. You’re misattributing it.

so what altitude was it maintaining when it went over alaska?

The dumping of excess fuel would have been done after satellite deployment, which as per this page: https://www.nasaspaceflight.com/2022/07/starlink-4-25/ is at 230 km (140 miles). This is way, way above the atmosphere and there is no way it would have produced any effects at ground level.

Whatever happened at your place, it was nothing to do with this launch.

Reply on news.ycombinator.com