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I had understood that regular missiles (such as ICBMs) are pretty much unstoppable too. There are some anti missile programs but publicly available test results

I had understood that regular missiles (such as ICBMs) are pretty much unstoppable too. There are some anti missile programs but publicly available test results are poor, even with extremely favorable test conditions. Why is this topic in the news right now?

mdorazio 7y ago
The Iranian missile that shot down the US drone was of the hypersonic variety (though I’m pretty sure just about any modern SAM could shoot down a drone), so people are more interested than previously.
jandrewrogers 7y ago
ICBM intercept has been a solved problem for (at least) a quarter century in the US, the core capability is quite reliable. The practical gaps show up in two tangential areas: upgrading systems designed for anti-aircraft applications to also intercept ballistic missiles and enabling kinetic intercept on hypersonic rocket platforms. The first case, which includes examples like the Patriot missile system, are making missile systems do something they were never designed to do. You can only modify them so far but it is cheaper to modify them than to design an entirely new system, if you can make it work. In practice though, many of these are being slated for replacement as it was a stopgap measure. The second case is more interesting. Conventional missile motors designed for ballistic intercept can consistently hit the target. But they are too slow to close the distance to the target, allowing the inbound missile to get closer than the military would like. Hyperkinetic interceptors can close the target very quickly, but the materials performance envelope required does not play well with precise terminal guidance systems due to ablation of the missile as it transits the atmosphere. Basically, the necessary precision of control could not be delivered over the entire flight time due to materials degradation. (This is related to why incoming hypersonic missiles have limited maneuverability -- maneuvering destroys the structural integrity of the materials it is made from.) The US appears to have solved the problem of hyperkinetic intercept of hypersonic targets in recent years. I think what confuses people is that the tests of new systems are only designed to test the things that currently don't work well. They know they can reliably discriminate decoys and do kinetic intercept, that is proven capability and doesn't need to be tested. What they need to test is things like precision terminal guidance when attached to one of these newfangled hyperkinetic rocket motors that ablates itself mid-flight, which turned out to be a much more difficult challenge.
- banku_brougham 7y ago
  >ICBM intercept has been a solved problem for (at least) a quarter century in the US, the core capability is quite reliable. This is a bold claim (one might say absurdly bold) that demands extensive support if you don’t want readers to dismiss your commentary completely. Let’s start from here: the problem solution can only be inferred from tests, because no ICBMs have ever been launched at a target. Those tests must have provided overwhelming confidence for the real world scenario. So how are those test result?
nitwit005 7y ago
> Why is this topic in the news right now? It's generally best to assume that articles like this happened because the companies involved contacted the reporters. I'd note that this article has both a product photo at the top, and a sales pitch in the headline ("hypersonic missiles are unstoppable").

mdorazio 7y ago

The Iranian missile that shot down the US drone was of the hypersonic variety (though I’m pretty sure just about any modern SAM could shoot down a drone), so people are more interested than previously.

jandrewrogers 7y ago

ICBM intercept has been a solved problem for (at least) a quarter century in the US, the core capability is quite reliable. The practical gaps show up in two tangential areas: upgrading systems designed for anti-aircraft applications to also intercept ballistic missiles and enabling kinetic intercept on hypersonic rocket platforms. The first case, which includes examples like the Patriot missile system, are making missile systems do something they were never designed to do. You can only modify them so far but it is cheaper to modify them than to design an entirely new system, if you can make it work. In practice though, many of these are being slated for replacement as it was a stopgap measure. The second case is more interesting. Conventional missile motors designed for ballistic intercept can consistently hit the target. But they are too slow to close the distance to the target, allowing the inbound missile to get closer than the military would like. Hyperkinetic interceptors can close the target very quickly, but the materials performance envelope required does not play well with precise terminal guidance systems due to ablation of the missile as it transits the atmosphere. Basically, the necessary precision of control could not be delivered over the entire flight time due to materials degradation. (This is related to why incoming hypersonic missiles have limited maneuverability -- maneuvering destroys the structural integrity of the materials it is made from.) The US appears to have solved the problem of hyperkinetic intercept of hypersonic targets in recent years. I think what confuses people is that the tests of new systems are only designed to test the things that currently don't work well. They know they can reliably discriminate decoys and do kinetic intercept, that is proven capability and doesn't need to be tested. What they need to test is things like precision terminal guidance when attached to one of these newfangled hyperkinetic rocket motors that ablates itself mid-flight, which turned out to be a much more difficult challenge.

banku_brougham 7y ago
>ICBM intercept has been a solved problem for (at least) a quarter century in the US, the core capability is quite reliable. This is a bold claim (one might say absurdly bold) that demands extensive support if you don’t want readers to dismiss your commentary completely. Let’s start from here: the problem solution can only be inferred from tests, because no ICBMs have ever been launched at a target. Those tests must have provided overwhelming confidence for the real world scenario. So how are those test result?

nitwit005 7y ago

> Why is this topic in the news right now? It's generally best to assume that articles like this happened because the companies involved contacted the reporters. I'd note that this article has both a product photo at the top, and a sales pitch in the headline ("hypersonic missiles are unstoppable").