Comment by ragle | Hacker News Reader

Comment by ragle | Hacker News Reader

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I can only speculate - but I'm really curious.

Looks like they may have launched a hypersonic missle that reached speeds of ~Mach 10[1], and the US (publicly, at least) seems to be lagging behind China and Russia in Hypersonic R&D - at least as of 2019[2].

How long would it take for a missile traveling at Mach 10 to reach a point where a high-altitude EMP attack[3] would cripple the west coast of the US?

Is that time longer than it would take for aircraft to return to a place where they could land? If NORAD spots a bogey moving that fast, is the rule right now just... everything stops until we understand what's happening?

Would love for someone who knows about hypersonics, NK missle capabilities, EMP attacks, etc. generally to say more.

[1] - https://www.reuters.com/world/asia-pacific/nkorea-launches-p...

[2] - https://www.defensenews.com/naval/the-drift/2019/11/15/dont-...

[3] - https://spectrum.ieee.org/one-atmospheric-nuclear-explosion-...

I'm not an expert, just a rocket enthusiast, but "hypersonic" really just means "near orbital velocities".

There's a lot of noise about admittedly really impressive low-altitude air-breathing scramjets, but - as your articles point out - those are still a long way away. The war hawks like to complain that we're not spending sufficiently many billions on developing futuristic hypersonic scramjet missiles. They point to our lack of a working scramjet as evidence that we're doing poorly. And look! North Korea's launched a hypersonic missile, China's launched hypersonic test missiles, Russia's launching hypersonic missiles; we're behind in the next war and it hasn't even started yet!

But those are just orbital or sub-orbital rockets at 50-100km altitude. Of course they're hypersonic, but that's not really that difficult - just build a big rocket, go up for a while, then turn sideways. We've been doing it since the 50s, tech is good enough now that relatively small companies like Firefly Space are launching small satellites to LEO with Series A fundraising of just $75 million. Tada! Hypersonic! The main point is that everyone has the capability to launch lots of these simple rockets, which can be devastatingly effective. Not as effective as highly steerable reentry vehicles or hypersonic scramjets, but enough that no one wants to be a target.

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