Hypersonic is not always as fast as you think

Moreover, hypersonic gliders are actually at a speed disadvantage compared with ballistic missiles of the same range. Ballistic missiles are also boosted to high speed by large rockets, before arcing through the vacuum of space. A glider, by contrast, spends most of its trajectory in the atmosphere, using aerodynamic lift to extend its range. The increased range comes at the cost of faster deceleration caused by atmospheric friction. One implication of this reduced speed is that hypersonic gliders may be more vulnerable to interception by U.S. “point” missile defenses (especially after such defenses have been optimized for that purpose). Like cornerbacks in football, point missile defenses are intended to protect small but important areas — such as U.S. military bases in the western Pacific.

Here is the full piece by James Acton.


I did not read the article. I do not think I need to. From what I can see from this site, the guy does not sound that he really knows what he is talking about. The difficulty in intercepting HGV, compared to ballistic missile, is the unpredictability of the trajectory of the maneuvering HGV, not because of its absolute speed.

But simplicity of hitting a HGV is to send multiple, low cost interceptors. In the swarm the attacking glider cannot turn fast enough. Five gliders, powered to 100 MPH will defeat a F22 or cruse missile in any air battle below 6,000 feet. The five gliders cots about $2000 each, and the four that miss the F22 return home for another attack.

In this scenario, all 4 trillion dollars of fighters and carriers are now worthless. Nothing is easier that swarming into an F22 against the blue and gray ski.

For proof, examine the patriot batteries destroyed by simple Yemini drones. Or consider the admiral in charge of carriers, he is not putting any carrier in the Persian Gulf again without a complete peace treaty to protect them.

Here is our admiral:
WASHINGTON: Iran has not drawn back to a less threatening military posture in the region following the attack on Saudi Arabia, the top US admiral in the Middle East told Reuters, suggesting persistent concern despite a lull in violence.“I don’t believe that they’re drawing back at all,” Vice Admiral Jim Malloy, commander of the US Navy’s Bahrain-based Fifth Fleet, said in an interview.The United States, Saudi Arabia, Britain, France and Germany have publicly blamed the attack on Iran, which denies involvement in the strike on the world’s biggest crude oil-processing facility. The Iran-aligned Houthi militant group in Yemen has claimed responsibility.Malloy did not comment on any US intelligence guiding his assessment. But he acknowledged that he monitored Iranian activities closely, when asked if he had seen any concerning movements of Iranian missiles in recent weeks.
What he means is simple. He cannot put a carrier into the Persian Gulf unless all parties, including the press, agree to keep their drones a two miles away.

This is new, a discovery made by our military in the last month after 40 years of sending carriers into the gulf. Things have changed. Our military is now flat footed, they have no swarming drone defenses ready for carrier of aircraft. They are about two years behind Israel, Iran and Russia.

Good comment. Our military's unpreparedness is really indefensible. An astute observer could have seen this development 10 years ago.

There is no defense against swarming drones with AI.

It's been over 40 years since the oil shocks of the 70s, but the US still decided it was a good idea to build SUVs. Now that is poor planning on behalf of the United States.

But if it makes you feel better, after decades of being ahead of you, Australia is now officially dumber when it comes to fuel efficiency.

The article is probably referring to something like this:


Which costs a bit more than $2,000.

Sorry, Matt, I misunderstood your comment.

You may have missed that these things necessarily fly high up and go fast. Your 100 mph drone can't fly above a few thousand feet, has negligible energy for maneuver or powering sensors, and even if it could manage it's top speed straight up into the tippy-top of the atmosphere, would take uselessly long to do so.

There's no way a drone that has the properties of a crippled stinger missile is going to threaten regular aircraft, much less something like this.

That was my reaction too, but the article does address that issue:

"If capable of adjusting their heading rapidly enough, these gliders could indeed defeat defenses by dodging interceptors. But executing rapid maneuvers without sacrificing the accuracy necessary for military effectiveness presents a significant technical challenge. There is no evidence that China, or any other state, has yet surmounted it."

He makes that assertion without providing evidence, OTOH it's not implausible. As other commenters have said, the real key may be drones that can defeat HGVs -- or for that matter aircraft carriers.

These technological decisions require a diverse portfolio of solutions, because no one has a good enough crystal ball to predict what the truly important military technologies will turn out to be.

Here are a couple of examples. In the late 1800s, the invention of the Whitehead torpedo (i.e. a self-propelled torpedo of the sort that we think of today; prior to that a "torpedo" meant what nowadays we would call a "mine") posed a potential existential threat to navies that were based on big ironclads or battleships. Major navies were very concerned that swarms of cheap little torpedo boats could overwhelm a navy of traditional big ships.

As it turned out, that didn't happen. Big ships added numerous batteries of secondary guns to fight off torpedo boats. More importantly, the truly important and innovative ship was invented: the torpedo boat destroyer, which we now simply call a destroyer. Have several of them escort your capital ships, and the torpedo boats didn't stand a chance. And destroyers turned out to be hugely useful for pretty much all of the major naval roles: anti-submarine warfare, anti-aircraft, short bombardment, high speed raids, escorting bigger ships or operating on their own in flotillas, often they were even pressed into service as amphibious attack ships and emergency cargo vessels. Little bitty torpedo boats couldn't do that, and couldn't actually threaten a major naval force.

Airplanes are another example, in this case of eventual success. Pretty much as soon as they were invented, militaries started scheming about how they might be used. But for decades they were too frail, too short ranged, too lacking in payload, and too inaccurate (both with regards to navigation and to bomb aiming) to do decisive damage to the enemy. Historians now deride the World War II admirals who thought that battleships rather than aircraft carriers still ruled the waves. The thing is those pro-battleship admirals were almost certainly correct until at least 1936 or so. Early naval attack aircraft were too weak to decide a battle.

But by 1941, and probably earlier, aircraft had become decisive, as the Bismark and US Navy discovered to their chagrin. (And the Italian navy at Taranto in 1940.)

So airplanes in fact did become a critically important weapon -- but it took over three decades for this to happen.

Where do drones -- and HGVs -- fit in these stories? And where are they on their timeline of technological development? Who knows?

I think a reasonable guess is that future militaries will feature swarms of drones, including anti-drone drones (just as fighter aircraft became vital to defeat the enemy's attack aircraft).

But how soon they will be decisive, who knows. In the meantime the US military has to work on multiple technologies of unknown true utility (e.g. cryptography and radar turned out to be very important in World War II but other exotic high-tech weapons such as homing torpedoes and jet aircraft did not).

1936 being the year the Fairey Swordfish went into production.

The Italians, and the allies also learned a hard lesson when the Italian Navy surrendered to allies and the Luftwaffe attacked it en route with guided bombs. Martin J. Bollinger in "Warriors and Wizards: The Development and Defeat of Radio-Controlled Glide Bombs of the Third Reich" covers this very well.

But American anti-air proximity fuses and just generally better gunnery control was often able to stop air attacks cold or with minimal damage. This occurring even as early as the Battle of Midway. And it is notable by the end of the war, the guided bombs, had lost a lot of their effectiveness. Given how ruinously expensive it is to build a plane, train a pilot just to (try and) crash it into a ship, the kamikazes were only effective in that even in WW2, the United States could be very loss averse compared to other combatants at times.

To my mind, the big unstated danger is the increasing effectiveness of non-nuclear submarines. Since they are not very noticeable in peacetime, they don't get much press. But I have yet to hear what the answer was to the soviet wake guided torpedoes - and that isn't even knew technology.

+1 for effective air defense and the threat of subs.

With respect to drones, if they clump, they're vulnerable to anything that fragments. If they don't clump they're just a bunch of slow-moving short-range projectiles.

Now, if I recall correctly, there's something to be said for mixing fast-moving and slow-moving projectiles. In anti-ship parlance it's called streakers and dancers. Historically the USSR favored streakers and the USA favored dancers, but a mix has benefits. Not least because you can't specialize your air defense mix against a presumed threat.

I wouldn't be surprised to see a bunch o'drones replace a unitary warhead or traditional submunitions for some applications. Their potential to persist for minutes if they don't come too close to a defended target puts them halfway in between bombs and mines.

Good comments.

"To my mind, the big unstated danger is the increasing effectiveness of non-nuclear submarines."

I remember reading a couple of decades ago that non-nuke subs were even harder to detect that nuclear-powered ones -- which have somewhat noisy nuclear reactors or more importantly the cooling equipment and other associated machinery to run the reactors.

Whereas a non-nuke sub using its batteries is like a Prius sneaking up on an unwary bicyclist.

However I don't know if that's still true. For awhile, I think the biggest noise source was the sub's screw/propellor but high-tech research (that IIRC got leaked to the Chinese) may have quieted them now.

The question is, I guess, what will be the weapon of choice for sinking those aircraft carriers around which the USN is built.

Mines. Or to use their more traditional name torpedoes. These don't have to destroy ships, they just have to render them useless by convincing the ships to stay home. They are hard to detect and while passive impossible to distinguish from thousands of pieces of rubbish that will have been dropped as decoys. Once they become active they behave as we think of a modern torpedo and rapidly move towards a vessel and destroy, disable, or damage it.

Clearing everything that is potentially a mine will be a huge effort and may require carriers carrying automated mine clearing drones to protect the carriers carrying aircraft.

Yeah, torpedoes are a much bigger threat.

If the US really does have something to fear from the Chinese (or the Bolivians or Finns or Greenland Inuit) why not just bury nuclear weapons in their major cities that can be detonated by remote control? Of course, the Chinese or the ennimi du jour would also have control over nuclear weapons staged in Washington, DC, New York, and other large cities. This situation wouldn't be any different than the current one except the expense of delivery and defense systems could be eliminated. The concept probably was explored in a Star Trek episode I missed.

Just don't get caught shipping in your nukes. That would be frowned upon.

It involves giving nukes to spies for whom the word "deception" is in their job description. Then there is the problem of how to use the asset. Do you announce, "We have nukes in 20 of your cities. Do as we say or we'll blow them up." Congratulations, you've just become the most hated nation in the world and no ship or plane or vehicle that came from your country will ever be allowed into another country again -- at least not with an exhaustive search. If the purpose of hidden nukes is retaliation after a enemy's first strike there is no deterrent if you can't tell people they exist. But nuclear missile submarines play the same role and you can tell everyone you have them.

Since this is by-far the least stealthy kind of weapon ever proposed, it's just waiting for it to become a big enough threat to warrant countering it.

The one issue I'm aware of is that interceptors targeting this sort of thing necessarily have to be fast, and they have to operate in the upper atmosphere. Those requirements are a bit contradictory as your seeker head will be engulfed in a Faraday cage of plasma if you go much above Mach 7 to 9 depending on altitude, negating the usefulness of anything carried by the missile. You could still potentially talk to the interceptor through the wake to do cuing, but you lose a lot if the sensor isn't on the interceptor itself. I imagine you'll either need somewhat more interceptors because they can't go as fast as the exo-atmospheric ones, or they'll need to sprint and slow before unsheathing their sensors.

People talk about maneuverability, but giving the interceptor as much or more maneuverability (and energy) than the target is easy.

In the movie Angel has Fallen there is a drone attack on the President. Then it clicks - there's no good defense against a smart drone swarm attack. Unless you're too fast to hit.

By the time drone swarm attacks are common, little-Aegis with little-Phalanx will be on every tank anyway. There's nothing fundamentally different about the problem.

And if you're going to spend the money on 1000 fancy guidance systems, would it not be smarter to stick a cheaper, more energetic, and more reliable rocket motor on the back of each of them? They're not going to look like quadcopters.

"Or consider the admiral in charge of carriers, he is not putting any carrier in the Persian Gulf again without a complete peace treaty to protect them."
or a change in the rules of engagement

Cannot read the article - but arn't gliders delivered by ballistic missiles?

They are launched by rockets. A ballistic missile follows a, well, ballistic trajectory from the time of engine cut-off until it lands. The articles I have seen are short on details but these things somehow manage to glide either upon atmospheric re-entry or without ever leaving the atmosphere in the first place while withstanding the enormous heat that would be generated by traveling at such speeds.

The Nazis apparently tried to develop such a missile to threaten North America but, of course, it was too difficult of an engineering problem at the time.

This article has more details: https://www.livescience.com/62653-russia-hypersonic-weapon.html

"Rather than generating its own power to reach hypersonic speeds, the glide vehicle catches a ride atop an intercontinental ballistic missile (ICBM). Typically, these rockets fly to space on an arcing trajectory before releasing warheads near the top of the parabola, and these warheads drop back down onto the target at hypersonic speeds under the power of gravity.

Rather than falling back to Earth, though, Avangard reenters the atmosphere at an angle and its aerodynamic shape generates lift that lets it glide down at hypersonic speeds, says Juliano, which allows it to travel further farther and maneuver as it descends." - this is from the article you linked to.

So simple ballistic missile warhead just falls down - but if it is a glider it can maneuver. It has one more capability over traditional ICBMs - it is silly to point that it is slower when gliding when it can fall down like a traditional warhead - but it can also glide and change directions.

Yes, it's basically an RV with some lift and a limited ability to interact with the atmosphere and control it's direction. In the future, they may add propulsion to extend range.

It's the least-stealthy weapon imaginable, but it operates in a regime that currently has few surface to air weapons designed to target it.

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