The Rise of Hypersonic Weapons • Hacker News Board

Re: The Rise of Hypersonic Weapons

#21

Post by CapitalistCartr » Wed, Oct 12, 2016, 2:03 PM UTC

LoSboccacc wrote: post #20

I think this article conveniently forgets to mention nothing hypersonic of sort will outrun lasers. lasers can't track of course and range is limited by factor like atmosphere and earth curve, but still, thinking about an hypothetical future scenario hypersonic weapons would just get lasered down by automated point defences all the same as conventional speed ordinance.

To shoot down a missile with a laser, you need a segment of light about 30-50 cm long, so the target doesn't move too much whilst burning a hole in it. In that little segment has to be the energy of at least a .50 BMG, so 20k joules of energy. In a portable form that can fire repeately, reliably. That's doable, but not easily.

Re: The Rise of Hypersonic Weapons

#22

Post by whalesalad » Wed, Oct 12, 2016, 2:04 PM UTC

Cozumel wrote: post #8

There's nothing 'hypothetical' about them like the article says, both Russia ( http://www.ibtimes.com/russias-secret-hypersonic-nuclear-mis... ) and China ( http://www.ibtimes.co.uk/china-successfully-tests-7000-mph-d... ) have operational hypersonic missiles. Whether they would use them when conventional weapons work just as well and are cheaper is debatable but they already have them.

I sat down with someone not too long ago who is leading the engineering effort on these for a Fortune 500 defense company. It's definitely a thing. It's interesting hearing about the types of materials that needed to be invented to hit a speed like mach 6 without completely disintegrating.

Re: The Rise of Hypersonic Weapons

#23

Post by JoeAltmaier » Wed, Oct 12, 2016, 2:07 PM UTC

CapitalistCartr wrote: post #21

LoSboccacc wrote: post #20

I think this article conveniently forgets to mention nothing hypersonic of sort will outrun lasers. lasers can't track of course and range is limited by factor like atmosphere and earth curve, but still, thinking about an hypothetical future scenario hypersonic weapons would just get lasered down by automated point defences all the same as conventional speed ordinance.

To shoot down a missile with a laser, you need a segment of light about 30-50 cm long, so the target doesn't move too much whilst burning a hole in it. In that little segment has to be the energy of at least a .50 BMG, so 20k joules of energy. In a portable form that can fire repeately, reliably. That's doable, but not easily.

That's about one nanosecond of light. E.g. travelling 1000mph is about a foot per millisecond. I think your light could be 1000 times that long and still hit essentially the same point on the target?

Re: The Rise of Hypersonic Weapons

#24

Post by CapitalistCartr » Wed, Oct 12, 2016, 2:10 PM UTC

I think tying aerospace advances/research to only the military potential, and thereby banning it all, would be stupidly counter-productive, and ineffective. If we want spaceplanes, supersonic intercontinental flights, etc. this is where the rubber meets the road. A test ban treaty would be as wise, effective, and narrowly-focused as DRM is at preventing IP-violating file sharing.

Re: The Rise of Hypersonic Weapons

#25

Post by CapitalistCartr » Wed, Oct 12, 2016, 2:14 PM UTC

JoeAltmaier wrote: post #23

CapitalistCartr wrote: post #21

Earlier quoted context omitted.

To shoot down a missile with a laser, you need a segment of light about 30-50 cm long, so the target doesn't move too much whilst burning a hole in it. In that little segment has to be the energy of at least a .50 BMG, so 20k joules of energy. In a portable form that can fire repeately, reliably. That's doable, but not easily.

That's about one nanosecond of light. E.g. travelling 1000mph is about a foot per millisecond. I think your light could be 1000 times that long and still hit essentially the same point on the target?

Travelling 1000mph is about mach 1.3. Hypersonic is mach 5 to perhaps mach 15, if our space launch research goes well. The target has to travel less than about 5 mm in that time. A foot would schmear the light too far.

[Edit] OK, I've done a bit of calculating, and I think you're right. The laser pulse could be a maximum of about 175 meters long.

Re: The Rise of Hypersonic Weapons

#26

Post by ekianjo » Wed, Oct 12, 2016, 2:14 PM UTC

> would be able to knock out a target’s nuclear capabilities fast enough and thoroughly enough to pre-empt any attempt at a retaliatory strike.

Did the author completely forget about nuclear subs?

Re: The Rise of Hypersonic Weapons

#27

Post by ekianjo » Wed, Oct 12, 2016, 2:17 PM UTC

3pt14159 wrote: post #17

nprecup wrote: post #15

Earlier quoted context omitted.

A hypersonic vehicle can travel much faster than that. We're talking about the ability to strike targets anywhere on the globe in minutes. That IS destabilizing. The example of striking carrier groups in the pacific is only the tip of the iceberg. This race amounts to a global game of chicken, and the stakes of a mistake are world war. Let's hope cooler heads prevail. On the other hand, there are some pretty amazing…

Not if you run the simulations. A city or three might get nuked in a tit-tat-tit exchange, but total war isn't currently likely. During the 60s and 70s there was the _chance_ we could just nuke all their nukes at once and maybe they'd get London, NY, or Washington, but we'd survive. A total strike is no longer even a first reach option because even if they level us and somehow cripple our nukes or kentic weapons we c…

Thats not how the chain of command would actually work in a nuclear exchange. You are much more likely to go all in anyway.

Re: The Rise of Hypersonic Weapons

#28

Post by justavoice » Wed, Oct 12, 2016, 2:24 PM UTC

LoSboccacc wrote: post #20

I think this article conveniently forgets to mention nothing hypersonic of sort will outrun lasers. lasers can't track of course and range is limited by factor like atmosphere and earth curve, but still, thinking about an hypothetical future scenario hypersonic weapons would just get lasered down by automated point defences all the same as conventional speed ordinance.

you don't even need lasers to shoot them down. They won't be able to jink very well, so a scatter-shot shotgun type of defense system would work very well. The real key will be to have a point-defense system with look-down shoot-down capability that can be deployed at enough distance from the protected asset to ensure that even a detonation of a nuclear hypersonic missile would cause minimal to no damage.

Re: The Rise of Hypersonic Weapons

#29

Post by JoeAltmaier » Wed, Oct 12, 2016, 2:25 PM UTC

CapitalistCartr wrote: post #25

JoeAltmaier wrote: post #23

Earlier quoted context omitted.

That's about one nanosecond of light. E.g. travelling 1000mph is about a foot per millisecond. I think your light could be 1000 times that long and still hit essentially the same point on the target?

Travelling 1000mph is about mach 1.3. Hypersonic is mach 5 to perhaps mach 15, if our space launch research goes well. The target has to travel less than about 5 mm in that time. A foot would schmear the light too far. [Edit] OK, I've done a bit of calculating, and I think you're right. The laser pulse could be a maximum of about 175 meters long.

A foot of light is necessary if you focus on a millionth of a foot of target. A longer bolt is acceptable if tolerances are looser than that. And they probably are. 5mm is about 1000X larger than that.

Re: The Rise of Hypersonic Weapons

#30

Post by 3pt14159 » Wed, Oct 12, 2016, 2:32 PM UTC

ekianjo wrote: post #27

3pt14159 wrote: post #17

Earlier quoted context omitted.

Not if you run the simulations. A city or three might get nuked in a tit-tat-tit exchange, but total war isn't currently likely. During the 60s and 70s there was the _chance_ we could just nuke all their nukes at once and maybe they'd get London, NY, or Washington, but we'd survive. A total strike is no longer even a first reach option because even if they level us and somehow cripple our nukes or kentic weapons we c…

Thats not how the chain of command would actually work in a nuclear exchange. You are much more likely to go all in anyway.

Chain of command starts with the president. Look to how Moscow has acted multiple times when there were nuclear worries due to faulty equipment. Multiple times they waited until confirmation of a hit. Now thank goodness nuclear weapons haven't been used since multiple parties have had them, but had a strike actually occurred what do you think the response from Moscow would have been? Full military preparedness (obviously), including potential launching of a tit for tat response. But what do they have to gain from launching everything? For all they know some insane general in America launched the thing. If they don't see anything else coming why would they commit suicide by launching everything?

There is no benefit.