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I read this question and was struck by something "obvious": why are not ICBMs built using "stealth" technology? A rocket, basically a pipe, must be much easier to "stealthify" than a irregular vessels like a plane or a ship.

Furthermore, according to the question above, the radar used to detect these missiles was using very low frequencies. AFAIK that means it wouldn't be good at detecting small objects. Compared to ships and planes an ICBM is quite small, making it even more motivated to build it stealthy.

d-b
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    As discussed in several of the answers to the linked question, making it harder for the opposition to see your missiles actually increases the risk to you because it increases the doubt the enemy have in their own safety. – Steve Bird Nov 22 '18 at 22:20
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    This is an stealth aircraft, and it does not resemble at all a pipe. So while your guess that a cilindrical object may have a lower radar signature sounds superficially interesting, I am afraid that it needs some proof. – SJuan76 Nov 22 '18 at 22:27
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    Even if an ICBM could be made stealthy (assuming one would want to do so), the launch would still be detected from satellites, which could then acquire and track the missiles visually. They generate quite a heat signature / trail which is easy to track on ascent. – Kerry L Nov 23 '18 at 00:04
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    In addition, 1) Stealth technology is relatively new, and the missiles (US ones, anyway) are fairly old; and 2) Until fairly recently, once the missiles were launched, there wasn't anything you could do about them anyway. – jamesqf Nov 23 '18 at 02:09
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    @KerryL So what is the purpose with radar if satellites can detect them - and not be jammed or disturbed - anyway? – d-b Nov 23 '18 at 08:36
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    @hensti I didn't say radar has no purpose, I merely pointed out that defeating radar would not make an ICBM invisible. The heat signature can be tracked by other high tech means. I was at NASA in the 1980's when there was a large transfer of knowledge taking place with the Air Force to give them their own heavy launch capabilities for delivering payloads to low and geo orbits. I helped set up one of their systems at Colorado Springs - there are many ways to detect and track ICBM launches and trajectories. – Kerry L Nov 23 '18 at 14:37
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    @hensti: The early warning radar dates from before satellites, and originally was intended to detect aircraft, not missiles. There's also the advantage of using multiple, independent systems to perform critical functions. – jamesqf Nov 23 '18 at 17:33

3 Answers3

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Stealthy ICBMs are pointless

Making the missiles radar-stealthy isn't useful, for quite a lot of reasons:

  • The curvature of the earth puts all current ICBM launch sites well below the radar horizons of other countries.

  • Over-the-horizon radars use long wavelengths, long enough that shaping the missile for stealth doesn't do any good, because it's much smaller than the wavelengths you need to be stealthy against.

  • For the above reasons, early-warning systems that are intended to detect missile launches all use satellites with infra-red sensors. An ICBM is a rocket, and cannot avoid having a hot exhaust plume.

Stealthy ICBM warheads are somewhat useful

After the rocket stages of an ICBM have burned out, the warheads and decoys are released into slightly different trajectories, heading for their various targets.

  • Making the warheads radar- and infra-red stealthy makes detecting them harder, and thus attacking them with counter-missiles or (someday) directed-energy weapons harder. This makes them safer during their flight above the atmosphere.

  • The French TN 75 warhead is apparently stealthy. It was developed more recently than the known US and Russian warheads.

  • A stealthy warhead is attractive to a country like France, with access to high technology, but a small inventory of warheads, because their expected target is Moscow, and Moscow has a missile defense system.

  • The US has lots of warheads, and may find it simpler to saturate Moscow's defenses than to build special warheads for the job. Or it may have built stealthy warheads without telling anyone.

  • Once a warhead re-enters the atmosphere, it can't be effectively stealthy because the extremely hot gas surrounding it is very conspicuous to infra-red detection and is easily detected with radar. However, there's very little time left for interception before the warhead detonates.

John Dallman
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There's not need for that. They are stealthy enough as it is. It is already very difficult to spot an ICBM launch. You need pretty advanced radar systems to begin with. But that is just the start.

A missile doesn't need escape velocity which is 11 km/sec or 40,000 km/hour. But it still flies much faster than airplanes at 13.000 km/hr. Again, you need very good radar equipment to track something that fast and (probably) that far away. (thanks for the correction, @gdir)

The missile will loose its boosters in flight, and once in reach of the target(s) dumps its payload. The number of MIRV's varies per missile/type/country, but there is no obligation to load bombs only. They can easily add a few dummies, and some additional clutter to confuse radar systems.

Jos
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    No, a ballistic missile does not need escape velocity. You need escape velocity if you want the rocket not to return to earth. Unfortunately ICBM do return to earth. Wikipedia lists a maximum speed for the Poseidon ICBM of 13000 km/h. – gdir Nov 23 '18 at 05:03
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    Note that due to reentry speed ICBM on the final part of its trajectory will be sheathed in a layer of a superheated, ionized air, which will make it almost as bright as sun on any detection system. Can't hide that by stealthy construction, decoys are the only way to go. – Danila Smirnov Nov 23 '18 at 06:06
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I believe some missiles - some cruise missiles to be more specific - are designed with stealth features.

Jason Tan
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