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DARPA's hypersonic scramjet achieves successful flight

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Re: DARPA's hypersonic scramjet achieves successful flight

#121

Post by JumpCrisscross »

jhgb wrote: post #118
JumpCrisscross wrote: post #113

Earlier quoted context omitted.

> even if you can detect them they are too fast to intercept? No. They still travel far slower than ballistic missiles. Their advantages are in being able to fly low and (theoretically) manoeuvre to avoid interceptors. They’re an evolution of cruise missiles, not strategic ballistic missiles.

But maneuvering at high velocities won't be that easy. As far as I understand it, your lift/drag ratio decreases appreciably with increasing Mach numbers. So either you'd have to limit your maneuvering, or you'd have to have a propulsion unit with ridiculous amounts of thrust - at a situation when any amount of useful thrust is hard to obtain, since we still don't know really well how to do propulsion in this regime.

As a former aerospace engineer, I’m sceptical of the strategic value of hypersonics. Tactical? Sure. They’d have a better chance of taking out SAMs, light radar, et cetera. But the talk about these being carrier killers is, based on everything we’ve seen, off the mark. (Spending the cost of one hypersonic on a swarming attack would probably do more damage.)

Re: DARPA's hypersonic scramjet achieves successful flight

#122

Post by WhisperingShiba »

merpnderp wrote: post #74
WhisperingShiba wrote: post #61

Earlier quoted context omitted.

One prominent one is that we use fear to control other countries instead of love. We spend so much human talent on defense, and sure we got a bunch of great technologies, but who's to say that we wouldn't have got them through some other avenue, later? Or perhaps even better technologies. I only speculate about the former, but I am quite certain a lot of the violence in the world has been caused by American Neo-colon…

How did the US fuck over Russia in WWII? And are you aware of the billions of foreign aid many countries get from the US which is tied to issues like human rights, freedom, and democracy?

The US let the Russians break themselves fighting the Eastern front while they invaded north Africa. The North African front was basically secure while Stalingrad was happening, and if the US applied more pressure to Germany in this period, as the Russian requested, the Germans probably would not have done so much population damage to Russia.

Bitterness of this fueled a lot of ideological tensions. I was also taught that a large motivation of dropping the Bomb was to scare the Russians.

Source: My Highschool education. Obviously, commentary on WWII is not objective, but I stand by my thesis, considering the actual action that the United States engages in in present times. Its in our history to be both ideologically driven and meta gamers.

Re: DARPA's hypersonic scramjet achieves successful flight

#123

Post by sudosysgen »

jhgb wrote: post #84
sudosysgen wrote: post #79

Earlier quoted context omitted.

Plasma stealth is an existing approach to radar stealth that is made easier by hypersonic speeds. Infrared targeting of multiple hypersonic missiles is easier said than done. The missile you're hitting them with is going to be heating up the air around the camera probably at the same temps as the missile it's intercepting, and a base station wouldn't have enough resolution to guide a missile accurately from 100+km aw…

> The missile you're hitting them with is going to be heating up the air around the camera probably at the same temps as the missile it's intercepting That would only apply if it were to hit it at comparable speeds. That's not necessary in many cases, especially in point defense when the target is heading towards you. Furthermore the limited time of flight of the interceptor might also allow for active cooling of the…

Interception against an actively manoeuvring target is a question of kinetic energy. If the intecepting missile is smaller all the hypersonic missile has to do is zig-zagging randomly and you're toast.

If you're going to wait for the hypersonic missile to be close enough that this isn't a problem, you have the issue that your missile won't be able to manoeuvre right and might still be building up velocity. Plus there won't only be one!

> the interceptor might also allow for active cooling of the IR window in that brief period.

The issue isn't the IR window, it's the air directly in front of the interceptor missile, which has to target from the frontal aspect.

>Also, even detection from a fixed ground base (or from space - see SpaceX's newest missile detection project) is still detection in the first place, which is what I was commenting on. Wasn't even going to veer into interceptor guidance, but I'm sure there's multiple ways to do it.

Detection is not enough. We can already detect missiles from satellites even. The issue is calculating their velocity accurately and locating them at +- 10m from 100km+ away is not feasible without really large apertures and pretty long focal lengths. You wouldn't be able to accurately track more missiles than you have optics and the optics would be mind-boggingly expensive. Besides that, the target acquisition radar to maintain a feasible or even physically possible relative aperture for target acquisition would be unable to resolve any detail about the missile, so it would have no way of telling the difference between a missile and a flare of the same brightness and color.

Re: DARPA's hypersonic scramjet achieves successful flight

#124

Post by gruez »

burkaman wrote: post #114
JumpCrisscross wrote: post #103

Earlier quoted context omitted.

> replaced the word "soldier" with "warfighter" Technically, only the Army has soldiers. The non-exclusionary term used to be “men and women in uniform,” but that got tired, so I guess we get “warfighters” now.

We also have "serviceperson", but you can't sell Call of Duty games that way.

The one fps game that contained "warfighter" wasn't call of duty. https://en.wikipedia.org/wiki/Medal_of_Honor%3A_Warfighter

Re: DARPA's hypersonic scramjet achieves successful flight

#125

Post by sudosysgen »

qaq wrote: post #45
sudosysgen wrote: post #36

Earlier quoted context omitted.

Ukraine did not have as much of a choice as one would think. All the nukes were set up to be controlled by Moscow and it would have taken enough time to bypass the controls that the Russian army could feasibly have invaded or destroyed them.

They were not a major portion of Nuclear Weapons R&D and manufacturing were done in Ukraine including design and manufacture of majority of electronics including guidance systems, comms etc. as well as most top tear weapons were designed by Yuzhnoye Design Office (Dnepr Ukraine) and manufactured by Yuzhny Machine-Building Plant (Dnepr Ukraine)

Ukraine indeed had a lot of manufacturing and design of nuclear weapons. Even then the control, launch and timings were all centralized in Moscow. They would have had to reverse engineer and hack a lot of it amidst attacks from Russia and perhaps even the US.

Re: DARPA's hypersonic scramjet achieves successful flight

#126

Post by Gravityloss »

pengaru wrote: post #92
Gravityloss wrote: post #82

Earlier quoted context omitted.

The SR-71 was very complex. For example it had multiple heat exchangers to get rid of heat, to transfer it to the fuel before it was combusted. The titanium structure was complex to maintain. Welding needed to be done in "bubble" work stations under protective gas.

> The titanium structure was complex to maintain. Welding needed to be done in "bubble" work stations under protective gas Operational complexity is orthogonal, and tends to be inversely proportional to simplicity in implementation... For instance they needed to refuel the thing immediately upon reaching operating temperature in flight, since it leaked like a sieve on the runway until everything expanded. Rather than…

Oh come on. SR-71 was a complex military aircraft. Maybe it was not as complex as the space shuttle. Certainly much more complex than an F-16.

One can start here for example http://www.enginehistory.org/Convention/2014/SR-71Inlts/SR-7...

Re: DARPA's hypersonic scramjet achieves successful flight

#127

Post by lamontcg »

newsclues wrote: post #64
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…

There are offensive weapons that you advertise so that the enemy wastes resources to defend against. Having nukes for MAD is useless if no one knows you have a credible threat.

"Of course, the whole point of a Doomsday Machine is lost, if you keep it a secret!"

I sorta suspect that this is more about the fact that the US knows this isn't a secret to China and Russia, so they're using it as an opportunity to brag domestically and get more funding.

Re: DARPA's hypersonic scramjet achieves successful flight

#128

Post by sudosysgen »

jhgb wrote: post #120
sudosysgen wrote: post #13

Earlier quoted context omitted.

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.

> they are preparing for mass production of hypersonic air breathing missiles ...or so they say. Of course they've been preparing for mass production of T-14 and Su-57 for quite some time now. Any day now they'll get them, I'm sure...

T-14 is ready for mass production, it's just too expensive for the broke Russian government to buy enough of them.

3M22 unlike Su-57 has actually achieved it's goals. It has already been fired from ships and hit targets while achieving it's speed and altitude goals. Su-57 has not been able to achieve it's goals of being stealthy or being reliable so there is no reason it would be readied for mass production.

Re: DARPA's hypersonic scramjet achieves successful flight

#129

Post by trhway »

amelius wrote: post #6

US's answer to Russia's Zircon missile? https://www.military.com/equipment/weapons/why-russias-hyper... > U.S. Aegis missile interceptor systems require 8-10 seconds of reaction time to intercept incoming attacks. In those 8-10 seconds, the Russian Zircon missiles will already have traveled 20 kilometers, and the interceptor missiles do not fly fast enough to catch up.

No. Russian Zircon is to deal with the next after nuclear strategic threat to Russia - US aircraft carrier groups. US pursue hypersonic weapons for different purpose - fast global much less than nuclear strike capability, ie. being able to strike any given target anywhere in like under half an hour. And thus not really much of hypersonic development in US - the cheap ballistic would do it better, especially with SpaceX driving down the cost of it. DOD is already excited that almost immediate delivery of 100ton, ie. instead of several C-130, payload by Starship anywhere in the world looks to be under $50M.

Re: DARPA's hypersonic scramjet achieves successful flight

#130

Post by cdash »

_2d30 wrote: post #102
tomcam wrote: post #90

Earlier quoted context omitted.

Good call. Seems unnecessary, like the slow transformation of “emergency room “which used to be known as the ER to “emergency department“.

In fairness, emergency department is more sensible. They generally aren't a single room. Soldier to warfighter seems unnecessary. EDIT: It seems possibly using "warfighter" is more accurate as marines and pilots aren't soldiers?

Sure but then you get into the situation where even though the full name is Emergency Department they still refer to it as the ER and not the ED.
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