Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

U.S. Air Force says it conducted successful hypersonic weapon test

reuters.com

Post reply on HN
Print view View original

61–70 of 131 posts

Re: U.S. Air Force says it conducted successful hypersonic weapon test

#61

Post by thereddaikon »

ramesh31 wrote: post #38
robonerd wrote: post #26

Earlier quoted context omitted.

My money is still on Aegis BMD intercepting the missile during the terminal phase. Hypersonic glide-boost weapons are mainly for avoiding mid-course interception. When you're going hypersonic, 'maneuverable' is relative; the turning radius is quite huge and such missiles will be easy for Aegis to track during the terminal phase.

>When you're going hypersonic, 'maneuverable' is relative; the turning radius is quite huge and such missiles will be easy for Aegis to track during the terminal phase. Except the associated plasma shielding makes it invisible to radar. And the Russian ones are capable of sea skimming and maneuvering at mach 8 in the terminal phase. At those speeds, you're talking horizon to impact in seconds. We really have nothing…

>Except the associated plasma shielding makes it invisible to radar.

You mean makes it very visible to radar but blocks any rf emissions to and from the vehicle itself right? This is no different than reentry effects we see on spacecraft. They are easily tracked by radar but have a radio blackout period until they slow down enough.

>And the Russian ones are capable of sea skimming and maneuvering at mach 8 in the terminal phase. At those speeds, you're talking horizon to impact in seconds. We really have nothing that can touch it.

The Russian missile is a paper invention for propaganda. It effectively does not exist. And if it does then they only built one. It is not an operational weapon and never will be. Russia is a poor country that is run by thieves who siphon money from their military to buy mansions and yachts. Just like T-14 and Su-57, Zircon is a propaganda wunderwaffe that will never be in combat.

China is bigger problem. But at the moment they have just fielded boost-glide vehicles. Not scramjets.

Re: U.S. Air Force says it conducted successful hypersonic weapon test

#62

Post by robonerd »

ramesh31 wrote: post #53
robonerd wrote: post #44

Earlier quoted context omitted.

> Current Aegis and CIWS defensive tech will not hit something traveling that fast. Aegis BDM is designed to hit hypersonic reentry vehicles. CIWS is irrelevant, why even bring it up?

>Aegis BDM is designed to hit hypersonic reentry vehicles Ballistic hypersonic reentry vehicles. The entire point is that these new weapons are maneuverable in the atmosphere at mach 8+ all the way to the terminal phase.

They don't maneuver for shit in the terminal phase. Boost-glide weapons avoid mid-course interception by staying relatively low in the upper atmosphere rather than following a high ballistic trajectory well into space. Once they're in the terminal phase their maneuvering capability is comparable to older maneuvering reentry vehicles (which are nothing new; the novel part is skipping the ballistic mid-course phase.)

Re: U.S. Air Force says it conducted successful hypersonic weapon test

#63

Post by jstanley »

djmips wrote: post #11
oneoff786 wrote: post #4

I believe most explosives detonate in the air anymore. Is there a speed threshold where the kinetic energy is enough to justify not doing that?

I think there might be a grammar problem in your statement. What did you mean?

It's relatively common to use "anymore" to mean "nowadays".

I think it must have come from hearing things like "They don't do that any more" and not recognising "any" and "more" as separate words, but rather as a concept that just means "now", such that "They do that anymore" is equally valid.

Re: U.S. Air Force says it conducted successful hypersonic weapon test

#64

Post by rad88 »

ramesh31 wrote: post #24
robonerd wrote: post #19

Earlier quoted context omitted.

All ballistic missile reentry vehicles are hypersonic too. Talk of "hypersonic" without specifying the technology and actual capabilities is quite silly. Presumably hypersonic cruise missiles is implicit context.. but I don't believe the general public understands that and the media is doing a generally terrible job of communicating it.

>All ballistic missile reentry vehicles are hypersonic too Sure, but ballistic trajectories are trivially interceptible. It's not just about speed. The new arms race is with hypersonic glide vehicles that are capable of maneuvering all the way to the target at mach 8+. With that, the weapon becomes impossible to intercept with any existing technology.

A ballistic missile could be within a few hundred miles of any point near the coast and be there in less than 5 minutes. You're saying this is "trivial" to intercept, what does that mean?

Re: U.S. Air Force says it conducted successful hypersonic weapon test

#65

Post by gsibble »

kcb wrote: post #48
staunch wrote: post #12

My understanding is that Russia and China are building hypersonic glide missile so they can penetrate any US missile defense system, which the US doesn't really even have. And neither does Russia or China have an effective missile defense system that the US needs the capability to defeat. So it seems like an arms race without either side really having advanced to the point of necessitating a further step. Then again,…

> US missile defense system, which the US doesn't really even have Uh..Missile defense is a massive part of US Navy doctrine and is pretty much the primary purpose of every Destroyer, Cruiser, and soon Frigate in the Navy at this point. Without a doubt, the Aegis system and THAAD are the direct reason for these developments from China and Russia.

This. We have hundreds of Aegis boats sitting off our coasts waiting for it to rain MIRVs.

Re: U.S. Air Force says it conducted successful hypersonic weapon test

#66

Post by nimbius »

zozin wrote: post #16
cersa8 wrote: post #10

How much of this is hype and boasting about military advances. According to this article hypersonic missiles are far from practical https://www.scientificamerican.com/article/the-physics-and-h...

They are. Chinese and Russian “advances” in hypersonics are pure marketing. The US was testing scramjets in the 1960s. The US has a hypersonic space plane. Alas, the media fell for it and billions are now being spent on “catching up” with our “peer” competitors.

the missile in TFA only achieved fivefold the speed of sound. Russias Avangard moves at twenty-seven times the speed of sound. thats faster than the re-entry speed for the space shuttle endeavor. it also advertises a newfound maneuverability.

Americans under-estimate their adversaries sadly quite often. when the TU95 bear first arrived during the cold war era its specifications were habitually lowballed by analysts until it appeared on radar over Canada. When the RQ710 was deployed in Iran with the same arrogant impunity, it was intercepted, landed, and dissected. heck, we spent about two decades insisting we could depose a cuban leader and just as long insisting we would "win" against the taliban.

and when the united states assumed china incapable of a cryptographic advantage, the nation summarily identified and executed more than a dozen spies thanks in part to dismissive hubris.

https://www.reuters.com/article/us-usa-china-espionage-idUSK...

the absolute worst thing you can do is dismiss a capable enemy.

Re: U.S. Air Force says it conducted successful hypersonic weapon test

#67

Post by aidenn0 »

oneoff786 wrote: post #4

I believe most explosives detonate in the air anymore. Is there a speed threshold where the kinetic energy is enough to justify not doing that?

About mach 8, but then you need to actually hit your target.

For ground based targets that's probably fine (in fact for slow-moving, armored targets kinetic-energy penetrators are already a thing). For anti-aircraft fire the goal is to get "close enough" that the explosives will damage it.

Re: U.S. Air Force says it conducted successful hypersonic weapon test

#68

Post by adrian_b »

theptip wrote: post #36
zmgsabst wrote: post #18

Earlier quoted context omitted.

Not really. Even for hypersonics, the efficiency of chemicals at storing energy and then releasing it is hard to beat. 1 kg of TNT produces 4.2MJ; to get the same energy in 1kg of projectile you’d need to travel at ~6500 miles per hour. (About mach 9 at sea level.) The role of hypersonics is in application: - sudden attacks, to prevent response - low altitude, high velocity attacks, to defeat intercept - penetration,…

Appreciate the detail. I'm not sure I see the conclusion as obvious though; if a 2kg weapon is going Mach 20 (as the weapon in the OP apparently does), with 1kg of that being TNT, then the explosives only provided 20% of the energy (rounding to the nearest 10% to make the example clearer). If you just lobbed the same 1kg weapon at Mach 20 then you'd have halved the weight, and reduced the energy to 40%. Presumably lo…

When close to the ground, something flying at Mach 10-20 would either be deccelerated very quickly to much lower speeds, if flying passively, or require a very large mass of fuel to maintain the speed.

Moreover, it would be hard to avoid being partially vaporized before reaching the target. So hitting something at Mach 10-20 seems much more difficult than filling the missile with explosives and detonating it.

Weapons based on kinetic energy alone seem practical only against satellites or against targets that fly in the upper atmosphere.

Re: U.S. Air Force says it conducted successful hypersonic weapon test

#69

Post by aidenn0 »

manachar wrote: post #37
Buttons840 wrote: post #17

Earlier quoted context omitted.

Better we try to one up each other with fast cruise missiles than with more nukes. In fact, nukes are useless now, let's just get rid of all of them. (wink wink)

You joke about nukes, but since they're such an "unthinkable" weapon they've become almost useless for most people who have them. You need them so that others with fewer compunctions are not able to steamroll you, but as an actual help to the kinds of conflicts currently going on and likely to happen in the future, they're just not as effective. Whether that's fast cruise missiles, more powerful drones, more disposab…

Ask Putin about how useless having nukes is for preventing NATO involvement in the Ukraine...

Re: U.S. Air Force says it conducted successful hypersonic weapon test

#70

Post by ritwikgupta »

cersa8 wrote: post #10

How much of this is hype and boasting about military advances. According to this article hypersonic missiles are far from practical https://www.scientificamerican.com/article/the-physics-and-h...

Hypersonics are already being used in warfare today [1][2][3]. They are already practical weapons and gaining parity in offensive and defensive capabilities is critical.

[1] https://www.cnn.com/2022/03/22/europe/biden-russia-hypersoni...

[2] https://www.defenseone.com/threats/2022/05/russia-has-fired-...

[3] https://www.euronews.com/2022/05/10/russia-fires-hypersonic-...

Post reply on HN