The New B-21 Stealth Bomber to Be Revealed Later This Year, Senator Says

Have you considered that maybe just maybe Russia is not keen on starting a kinetic war with Israel? Not shooting down doesn't mean not detected.

Also, Russia has already delivered some S-500s into service. Their supply chains might be strained, but they are still functioning & mostly domestic sourced.

Ukraine is a poor example since Russia's approach is to induce fear by firing indiscriminately at civilian areas.

So it's impossible to gauge the accuracy of anything let alone the rarely seen Kinzhal missiles.

A cruise missile strapped to a plane is not what people mean when they talk about hypersonics, even if it is (barely) technically correct. The new class of hypersonic missiles are aiming to be Mach 20 or faster, and highly maneuverable in comparison, quite a different capability. This is the type of missile that has not been proven to work beyond testing yet.

The term "hypersonic missile" these days is short-hand for terminally-guided endoatmospheric missiles that can operate at hypersonic velocities. This is an extremely difficult engineering problem and there is no evidence that anyone has an operational weapon in this class.

Nothing in the Ukraine fits this description. Those are ordinary ballistic missiles, which naturally have hypersonic ballistic re-entry. There is nothing interesting about that, we've had it for 70+ years now.

A Kinzhal missile is not what people are referring to when they talk about "hypersonic missiles". They're usually referring to either maneuverable glide vehicles (lifting bodies for warheads that allow them to change course during the terminal phase), or air-breathing SCAMJETs cruise missiles that are both maneuverable and can fly at low altitude to avoid detection (well, other than the noise).

Also consider that russia's Kinzhal can go about mach 4-5. That sounds pretty bad, until you realize that good old ICBMs re-enter from space and travel in atmosphere somewhere between mach 15 and 20.

Fast missiles like Kinzhal are not new at all. As far back as the 60s the USA had the Sprint and Nike which could accelerate from the ground to mach 10 in seconds and would glow white hot from heating. Even maneuverable glide vehicles aren't new, the Pershing II could perform limited course changes during descent back in the early 80s. Yes, fast missiles are scary, but they're not in the same class as true air-breathing hypersonic weapons.

https://en.wikipedia.org/wiki/Nike_Zeus

https://en.wikipedia.org/wiki/Sprint_(missile)

https://en.wikipedia.org/wiki/Pershing_II

The SM-6 has some limited ability to intercept hypersonic weapons. This hasn't been tested in a realistic way yet.

https://seapowermagazine.org/vice-adm-hill-mda-pushes-space-...

'Cheap' / dumb ammunitions may be easier to produce in volume, so if you need to increase production it could be easier.

The B-21 is a fixed cost that is ready to go: just 'add water' (munitions) and you can have a higher pace of operations as long as you can feed the machine (B-21).

Yep. True. But amortized over the expected lifetime of the aircraft, it will still be orders of magnitude cheaper.

My point is to outline that the topic is complicated. There is a lot more to it than "x radar resolves y aircraft"

Cynical take: jobs program for the senators district.

Non-cynical take: Most modern aircraft are equipped with networking/avionics that allow information to be shared across multiple battle domains (army on land, air force, maybe space who knows). A stealth-ish (not completely invisible but still tough to track) aircraft that can perform this role as well as carry nukes might be useful in coming conflicts.

The radars of WWII could see these aircraft but with extremely low resolution. What THz phased array radars are in service right now?

> hiding from modern THz radar is impossible

Seeing a plane and targeting it as separate beasts.

It just needs to be invisible enough to have the planes be able to destroy targets before the enemy (a) detects and determines what you are and (b) launches a set of missiles to destroy you.

If stealth fails at (a) but buys you enough time to get out before (b) then it's still a successful technology.

"Stealth" means "as stealth as we can be", not "100% invisible".

Hiding in the THz is the easiest; paint it black and fly at night.

Lower THz, e.g. IR, is attenuated by the atmosphere. Useful but limited, and stealth planes are designed to make it harder (e.g. by mixing hot exhaust with cooler air above the wing, where the hot engine cannot easily be seen from the ground.)

> THz radar

I've got your THz right here (shines laser pointer at sensor)

You'll see puff pieces from radar manufacturers saying "we spotted your best stealth plane, game's up," but they tend to leave out critical details like how more sensitive radars tend to be more vulnerable to jamming. Detecting a stealth aircraft in peacetime is a very different prospect from detecting a stealth aircraft in a hostile EW environment, which is itself different from an outright hostile environment where every radar pulse is a targeting opportunity for an anti-radiation missile.

Also, it's not black and white: range of detection matters. Shrink it enough and either your opponent has to put up more radars or you get the opportunity to slip through. Retro-reflective stealth is defeated by networked radar, but then the opposing forces have to maintain a network and you can try to disrupt that network. Even if you can't disrupt the network, it doesn't fit on a missile, so now the missile either can't target you or needs network communication to target you, and now you can try to go after the missile's network, which is wireless and even easier to mess with.

Stealth isn't necessarily an overriding factor these days, but it definitely gives you options and puts pressure on the opposition.

AFAIK it's the opposite. Low frequency early warning radars are able to detect the vague position of stealth fighter jets (like the F-35) because these jets need a vertical stabilizer to be able to do combat maneuvers. Knowing the vague position is good enough to route intercepting aircraft towards the threat but in theory you will be unable to target these jets with AA missiles because targeting radars can't see these jets until they're very very close.

Flying wing designs like the B-2 and B-21 don't have this issue and are mostly invisible to early warning and targeting radars.