(after writing this, I feel like the tone may look hostile? I don't mean to be, I just enjoy talking about this stuff. You're all good)

Not to claim any sort of expertise here, and we're also talking about military stuff that's under wraps. No posting of blueprints of kalibr missiles to win online arguments haha.

I remember online discussions of the dongfeng and the kalibr missiles. and people making this point. Friction from the air heats up the skin of the missile, causing problems with comms and detection, as well as limiting the materials used on the surface. Which, yes, is definitely a real thing that happens. However, I always felt that western observer's assumption that this was insurmountable was wrong. Bafflingly so.

Not that it's trivial to work around, but I always felt like it could be worked around in a number of ways.

• My first go-to would be to have an exterior surface that relies on a part in front of it to create a shockwave that deflects most of the air away from it. The shielding part would obviously gain a lot of heat, but the area behind it wouldn't suffer as much friction heat. Imagine the common image of a space shuttle coming in from orbit. The bottom gets very hot, the top part stays pretty cool. The soviet experience with supercavitation (albeit in torpedoes) is helpful here.
• Another method could be to blast the surface in question with refrigerants. The pressure from the refrigerants boiling could also move hot outside air away in the above method, and the refrigerants boiling would also cool the surface. Obviously, you'd have to carry a reservoir of refrigerant, but you'd need it for maybe 30 minutes or so max, and a small amount of liquid can turn into a lot of gas.

Based on what early reporting was saying about these design issues, I think western observers assumed a combination of gyros and accelerometers with detailed terrain maps for striking stationary targets. idk what they assumed for moving targets (the armchair generals just kind of assumed that a dongfeng couldn't hit a moving target like an aircraft carrier).

We know now that kalibrs are indeed functional weapons that can hit things, and also go very fast. So there is clearly some sort of solution at play. Given the cheapness and accuracy of modern consumer grade GPS tech (especially since kalibr missiles aren't riding in elevators), and that the solutions I've listed don't rely on particularly precise technology or dense computing, and that a hypersonic cruise missile is about as fast as the fastest air defence missiles (uh, I can expound on this point if you want), I think that kalibr isn't reliant on particularly fast computing in the missile.

I also think that "the west" has neglected both cruise missile and strategic AA technology, which tbf is fine for the wars they fight.