DARPA's hypersonic scramjet achieves successful flight • Hacker News Board

Re: DARPA's hypersonic scramjet achieves successful flight

#11

Post by masklinn » Sun, Oct 03, 2021, 4:57 PM UTC

imglorp wrote: post #4

I'm curious about the PR strategies at play when governments either saber-rattle or keep secrets. Announcing breakthrough, surprising even, HAWC tech seems to clue in opponents about what sorts of countermeasures they'd want to start developing. By contrast, the US has held the high-altitude Aurora/SR-72/whatever tech very close to the vest for decades, when it's pretty much obvious that a new generation of high alti…

> Announcing breakthrough, surprising even, HAWC tech seems to clue in opponents about what sorts of countermeasures they'd want to start developing.

It's pretty hard to hide hypersonic devices these days, and the concept is not exactly a secret: Russia and China are testing devices, and multiple other countries are working on developing their own.

Re: DARPA's hypersonic scramjet achieves successful flight

#12

Post by allenrb » Sun, Oct 03, 2021, 4:59 PM UTC

For a moment, reading only the first paragraph, I was hopeful that the problem of accelerating from subsonic to hypersonic had been solved. Alas, further down it makes clear that a booster was involved. Presumably a small solid rocket that accelerates to Mach 3-5(?) prior to scramjet ignition. Fine for a weapons system but will never be useful as transportation.

Is anyone aware of progress toward being able to reach these speeds without disposable boosters?

The SR-71 could make Mach 3 on its own but at incredible cost in fuel and complexity.

Re: DARPA's hypersonic scramjet achieves successful flight

#13

Post by sudosysgen » Sun, Oct 03, 2021, 5:03 PM UTC

masklinn wrote: post #11

imglorp wrote: post #4

I'm curious about the PR strategies at play when governments either saber-rattle or keep secrets. Announcing breakthrough, surprising even, HAWC tech seems to clue in opponents about what sorts of countermeasures they'd want to start developing. By contrast, the US has held the high-altitude Aurora/SR-72/whatever tech very close to the vest for decades, when it's pretty much obvious that a new generation of high alti…

> Announcing breakthrough, surprising even, HAWC tech seems to clue in opponents about what sorts of countermeasures they'd want to start developing. It's pretty hard to hide hypersonic devices these days, and the concept is not exactly a secret: Russia and China are testing devices, and multiple other countries are working on developing their own.

Russia is not really testing devices per se anymore, they are preparing for mass production of hypersonic air breathing missiles. We don't know too much as for China.

Re: DARPA's hypersonic scramjet achieves successful flight

#14

Post by [deleted] » Sun, Oct 03, 2021, 5:10 PM UTC

imglorp wrote: post #4

I'm curious about the PR strategies at play when governments either saber-rattle or keep secrets. Announcing breakthrough, surprising even, HAWC tech seems to clue in opponents about what sorts of countermeasures they'd want to start developing. By contrast, the US has held the high-altitude Aurora/SR-72/whatever tech very close to the vest for decades, when it's pretty much obvious that a new generation of high alti…

[deleted]

Re: DARPA's hypersonic scramjet achieves successful flight

#15

Post by panick21 » Sun, Oct 03, 2021, 5:14 PM UTC

allenrb wrote: post #12

For a moment, reading only the first paragraph, I was hopeful that the problem of accelerating from subsonic to hypersonic had been solved. Alas, further down it makes clear that a booster was involved. Presumably a small solid rocket that accelerates to Mach 3-5(?) prior to scramjet ignition. Fine for a weapons system but will never be useful as transportation. Is anyone aware of progress toward being able to reach…

SpaceX Starship will do this and be fully reusable. Starship can fly long distance with a reusable booster and somewhat shorter distances without a booster.

Granted, its not really 'flying' but it does reach the speed needed.

Re: DARPA's hypersonic scramjet achieves successful flight

#16

Post by pengaru » Sun, Oct 03, 2021, 5:16 PM UTC

allenrb wrote: post #12

For a moment, reading only the first paragraph, I was hopeful that the problem of accelerating from subsonic to hypersonic had been solved. Alas, further down it makes clear that a booster was involved. Presumably a small solid rocket that accelerates to Mach 3-5(?) prior to scramjet ignition. Fine for a weapons system but will never be useful as transportation. Is anyone aware of progress toward being able to reach…

> The SR-71 could make Mach 3 on its own but at incredible cost in fuel and complexity.

the SR-71 never struck me as "incredibly complex", the space shuttle however...

Re: DARPA's hypersonic scramjet achieves successful flight

#17

Post by Ericson2314 » Sun, Oct 03, 2021, 5:20 PM UTC

Atlantium wrote: post #8

jackschultz wrote: post #2

DARPA has such a list of impressive, world wide useful technologies that wouldn't have been able to be created without funding from the government at the time given the time and money and at time, unlikeliness to be successful [0]. It really sucks that there's a 'D' for 'Defense' at the front of the acronym. Their website says they're "creating breakthrough technologies and capabilities for national security". Horrib…

Many humans are quite aggressive. Pacifists are easily defeated by force. How can you have progress without security?

That's a straw man. The problem is tons of research and development won't happen without the state, but the main avenue the state funds development (as opposed to research) is the military.

There are many possible futures, and the world is highly non-ergodic, so there is a real cost here to biasing the development of technology in this matter. "Opportunity cost" doesn't do the concept justice.

We don't have to stop military research, but we should bring up the Arpa-E and other such things to bring balance to the situation.

Re: DARPA's hypersonic scramjet achieves successful flight

#18

Post by detritus » Sun, Oct 03, 2021, 5:22 PM UTC

allenrb wrote: post #12

For a moment, reading only the first paragraph, I was hopeful that the problem of accelerating from subsonic to hypersonic had been solved. Alas, further down it makes clear that a booster was involved. Presumably a small solid rocket that accelerates to Mach 3-5(?) prior to scramjet ignition. Fine for a weapons system but will never be useful as transportation. Is anyone aware of progress toward being able to reach…

I believe the descendant of HOTOL is intended to bridge that gap... https://www.reactionengines.co.uk/

Re: DARPA's hypersonic scramjet achieves successful flight

#19

Post by eganist » Sun, Oct 03, 2021, 5:33 PM UTC

Ericson2314 wrote: post #17

Atlantium wrote: post #8

Earlier quoted context omitted.

Many humans are quite aggressive. Pacifists are easily defeated by force. How can you have progress without security?

That's a straw man. The problem is tons of research and development won't happen without the state, but the main avenue the state funds development (as opposed to research) is the military. There are many possible futures, and the world is highly non-ergodic, so there is a real cost here to biasing the development of technology in this matter. "Opportunity cost" doesn't do the concept justice. We don't have to stop m…

> That's a straw man. The problem is tons of research and development won't happen without the state, but the main avenue the state funds development (as opposed to research) is the military.

The reason the op's comment is not actually a straw man (https://en.wikipedia.org/wiki/Straw_man) is because the first governments were developed out of a necessity to ensure a unity of peoples, the functioning of essential systems, and the protection of said peoples and systems. It's also why (for instance) the very first sentence of the US constitution has multiple touch points with national security:

> We the People of the United States, in Order to form a more perfect Union, *establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty* to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.

To summarize: defense is how so much of our monetarily non-viable societal advances take place because defense is primarily why governments exist at all. Even arpa-e (thanks for your edit—it's a good topic to bring up) exists to minimize our reliance on foreign energy, which is directly motivated by national security.

Re: DARPA's hypersonic scramjet achieves successful flight

#20

Post by echelon » Sun, Oct 03, 2021, 5:33 PM UTC

Ericson2314 wrote: post #17

Atlantium wrote: post #8

Earlier quoted context omitted.

Many humans are quite aggressive. Pacifists are easily defeated by force. How can you have progress without security?

That's a straw man. The problem is tons of research and development won't happen without the state, but the main avenue the state funds development (as opposed to research) is the military. There are many possible futures, and the world is highly non-ergodic, so there is a real cost here to biasing the development of technology in this matter. "Opportunity cost" doesn't do the concept justice. We don't have to stop m…

America is preventing Russia from antagonizing Europe, all the while we foot the bill for maintaining a capable military.

China is a looming threat. If you don't see that, I don't know what I can say.

Take away America's military and see what happens.

Tibet, Hong Kong, Taiwan, Spratleys, 9-dash, water rights, Belt+Road indebtedness, Crimea, Ukraine...

The US has to be strong out of necessity, and we get treated like shit for it. America is far from perfect, but it's Democratic and celebrates individualism and free speech. And I'm not persecuted for being LGBT. I'd hate to be in Russia or China where I'm told I can't think my own thoughts or have my own preferences.

If we didn't have to pay so much for our military capabilities, maybe we'd all get to enjoy the same free health care and social programs that Europe, Canada, and other nations enjoy.

Europe needs to carry some of this weight.