Hacker News new | past | comments | ask | show | jobs | submit login

I'm surprised they're talking bout having the landing pad 10km off shore--it seems like that wouldn't be far enough for noise reduction, both outgoing (rocket engines) and incoming (sonic booms).



Doubling the distance only gives you a 6db drop. So, the best approach is probably to have structures in the way to redirect sounds. Which should make a dramatic difference.


Unless the structure was miles high, wouldn't the sound just bypass it as it climbed above?


This mostly deals with ignition and static firing where the rocket is not moving. Rockets have ridiculous acceleration, but create a lot of noise on the ground. I assume being kind of noisy for 5-10 seconds a few times a day is not that big a deal.

Assuming ~20 stories aka 200 feet is reasonable at 100 feet per second acceleration aka just over 3 g's in 2 seconds the base of your rocket is just over the 20 story building and your doing 130 MPH. Even still that building is still going to be blocking a lot of sound as the fire is below that level.

7 seconds after launch your (5 after clearing the building) your doing 477 mph and have traveled 1/2 a mile. At 12 seconds your doing 820 mph and have traveled 2 kilometers up.

PS: Falcon Heavy is apparently ~160db vs 120db for thunder, which you can barely hear at 10km. So, it's going to be noticeable at 10km, but not that noticeable.


Guess we have to build a dome around the city.


I was thinking this was the use case for Hyperloop and the boring company... take an underground shuttle to the launch pad in 30 minutes or less...




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: