As salawat stated in the excellent parent post, >The key is really about detection A cursory search indicates ICBMs have terminal velocity comparable to, or hi

As salawat stated in the excellent parent post, >The key is really about detection A cursory search indicates ICBMs have terminal velocity comparable to, or higher than, of hypersonic missiles, at about 16...34'000 km/h. The key difference is that a ballistic missile has recognizable launch signature -you can detect it via satellites- and coasts high above the atmosphere for several minutes, during which it's readily detectable by radar. We already have tech that reliably intercepts & destroys ICBMs - counter-rockets like Sprint/HIBEX [1], lasers, and even small nukes. A hypersonic missile could fly low-ish [2], perhaps even "on the deck", thus evading long range radar detection. Still we could probably detect, from satellites, the heat signature of super-heated plasma around the missile. I think the most stealthy -and dangerous- scenario would be a slow (trans-sonic, or maybe Mach 2) low-level cruise to mask the heat signature, followed up by a hypersonic dash to the target. Essentially leaving very little time to make decisions and launch counter-measures. >If you are talking about putting the debris in its path after observing the incoming missile, how can it be stationary? Relatively stationary. Dispersing several tens (or perhaps hundreds) of kilograms worth of small metal cubes or balls in area of a few hundred meters ought to be enough to hit a hypersonic missile with reasonably high kill probability. Basically old-fashioned flak, except delivered by a small rocket. The missiles own high speed would be enough to cause destructive damage upon hitting even small piece. This photo [3] shows effects of impact of tiny 7 gram particle at comparable velocities - some 25'000 km/h. A gaping hole like that in the heat shield would quickly lead to further damage in a hypersonic flight regime [4], perhaps also aerodynamic instability. And that's if the initial shock doesn't disable the mechanisms right away. [1] https://www.youtube.com/watch?v=xZTjA44T6tY&feature=youtu.be&t=93 https://www.youtube.com/watch?v=xZTjA44T6tY&feature=youtu.be... [2] however low level hypersonic flight is very fuel-hungry, and causes tremendous heating; both significantly limit endurance [3] https://en.wikipedia.org/wiki/File:SDIO_KEW_Lexan_projectile.jpg https://en.wikipedia.org/wiki/File:SDIO_KEW_Lexan_projectile... [4] https://en.wikipedia.org/wiki/Space_Shuttle_Columbia_disaster https://en.wikipedia.org/wiki/Space_Shuttle_Columbia_disaste... was triggered by a small-ish hole of some 15...25cm in thermal protection