When space shuttle Challenger broke up over Dallas, Texas about 20 years ago it came in really low (steep angle of attack) and there was a sonic boom, felt like a garbage truck had driven into the side of the house at full speed. Woke me up from sleep at about 6am. Got out of bed to see what was going on, turned on the TV to find out it was the space shuttle.

People will tolerate a sonic boom once a quarter or so, but you've better have a really good reason, like national security.

> When space shuttle Challenger broke up over Dallas, Texas

That was Columbia, not Challenger. Challenger exploded on launch from Cape Canaveral.

Supersonic booms are extremely loud. Without solving that problem, these can not be flown over populated areas.

It’s currently illegal to fly past Mach 1 over land barring a few exceptions (eg: military training areas).

https://www.faa.gov/newsroom/supersonic-flight

Something I didn’t know about the sonic boom until discussions of this company is that it is continuous, not just at the point the plane passes the speed of sound. So a plane like this is constantly dragging a cone producing very loud noise behind it.

There has been some research in trying to minimize or at least spread out sonic booms by changing aircraft shapes and engine dynamics, but as far as I know they're all still experimental. Boom is going to live up to its name if it ever actually flies, which means staying over the water whenever they are operating in the supersonic regime.

Due to noise constraints supersonic flight is banned over land right now. If they lower noise pollution maybe laws will be changed.

A bunch of replies say that wouldn’t be allowed, but I heard sonic booms regularly while living near an Air Force Base in California. It didn’t seem to affect the hundreds of thousands of residents nearby. Is there an actual reason why we can’t have one every day at 10am or on some other regular schedule?

If you heard USAF sonic booms, they were probably over 15 miles offshore, or 15 miles inside an Air Force training range. They were probably not directly over your house.

A crosscountry scheduled supersonic flight will have to overfly populated areas twice a day - booming all the way.

(Something that causes a lot of confusion - people often think a sonic boom is an instantaneous thing that happens when the plane breaks the sound barrier - it is not, it’s a continuous shockwave that travels with the aircraft while it is flying above Mach 1; anyone on the ground who the shockwave passes over along the flight path hears a sonic boom)

If you’ve ever heard thunder from lightning 15 miles away compared to thunder directly overhead, that might give you some framework for figuring out the difference.

I remember growing up during the cold war in western Germany which was formally under the control of the allied forces. So they were allowed to go supersonic with the military jet aircraft and frequetly did so, even in rather populated areas (by German standards - in general, Germany is much denser populated than the US). It was a bit annoying but definitely survivable (here I still am).

I think it was a mistake for the US to ban supersonic flight outright and especially at all altitudes. I can't imagine a sonic boom being a huge problem, if you are 10 miles up or higher.

It really depends on where the sounds were generated, in my experience. Off shore sonic booms are loud, but fairly tolerable by the time the sound makes it to the beach. But I once heard two fighters go supersonic directly overhead in eastern Washington (they were pretty high up, even so) and the booms sounded like someone tried to bash in the front of the house. Not something you'd tolerate with any regularity.

I imagine because it’s a lot harder to successfully sue the USAF.

Because of the sonic boom, you can't be flying over inhabited areas. Regulations prohibit that.

I believe supersonic flight is currently banned over the USA (and most countries?).

A previous entrtant in this area seemed to suggest that efficiency dropped near mach 1, but then rose again to 95% at speeds around 1.4 so being able to stay at that speed may make it cheaper to run and maximize their USP of speed.