The US looked at this in the 50s and the 60s as Pluto & SLAM.
The consensus was that it was a dumb idea, especially after ICBMs were deployed. Their only benefit vs alternatives -- incredibly long flight time (on the order of months / circling the globe 4.5 times) -- doesn't allow you to do anything you couldn't already do.
This was pre-stealth, but I can't imagine it's easy to stealth something with a red-hot exhaust (remember, to have endurance, it's superheating air rather than combusting limited fuel).
Hypersonic re-entry vehicles are far more useful, but also harder to develop.
Honestly, this seems a pretty blatant attempt to trot out Cold War era technology for a ra-ra "look, we're still relevant" showing than new R&D.
For those curious on how a nuclear-powered missle could work...
On the Pluto project a ramjet scoops up air, and then the decay heat from a radioisotope is used to heat that air and expel it to generate thrust.
The range really is practically unlimited. The Pluto missle could have flown for months. Nuclear fuel just has over 1000x the energy density of fossil fuels (but lots of complexity around using that energy)
Hypersonic re-entry vehicles seem effective at beating missle defense systems, but a nuclear ramjet missle always in the air seems like it'd have other advantages. (First strike? Persistent threat even after all land/water based missle systems are destroyed?)
You can, at the very least, probably aim them a lot better or change the target altogether, for example for misdirection. An ICBM mostly goes up and falls down again on a ballistic trajectory, at least in a first approximation, they can of course correct the trajectory to some extend. On the other hand ICBMs are a lot faster which makes them harder targets for interceptors even if the trajectory is reasonably predictable.
I think the reason the project was shelved is that it did provide different capabilities, but none of those capabilities were actually useful in a military context.
That said, after a bit more review, there is one scenario where they would be useful -- launched en masse as a first strike weapon.
While easy to detect at radar range, the smaller boost signature does make launch detection more difficult.
Assuming a launch from the west coast, and design speeds comparable to Pluto (mach 4.2), you'd have about 9 min before they hit Midwest US silos.
Which is one of the other reasons we never developed them. Announcing loudly that you're developing something that's primarily a first strike weapon tends to make the other person jumpy...
One Cold War era tactic comes to mind, probably void now with modern interception.
A "failsafe point" is where you can stage bombers (or flying bombs in this case) in neutral airspace near your enemy, and have them orbit there for long periods. If things get more tense, you can stage more there without committing to a strike. With tankers, they can park there for days before being swapped out. Then if things turn sour, they're not as far from the target; they can drop to terrain following and go downtown for business. See the awesome Henry Fonda 1964 movie Failsafe for a period story about how talking to your bombers can go wrong.
Last October a mysterious radioactive cloud spread over Europe [1,2]. The source was traced to the Ural mountains between Russia and Kazakhstan. Although the amount of radioactive fallout in Europe was minuscule and harmless, there must have been a significant amount of radioactive material released at the source.
A few months ago, Putin announced Russia developed a nuclear powered missile with unlimited range [3] (really is was just 22 miles because "Russia"). The missile was reportedly tested in late 2017. Did Russia spew radioactive jet waste over their country during a field test of their nuclear powered missile?
A more likely explanation:
"The French IRSN has put forth the hypothesis in Jan-2018 that a possible reason for the release of Ru-106 radioactivity at Mayak-PA might be an unsuccessful attempt to extract the short-lived reactor-generated-isotope cerium-144 for the European/Italian nuetrino-detecton-project Borexino. Mayak-PA had agreed to deliver cerium-144 in early 2018, but canceled the contract in December 2017. Mayak PA was the only facility contractually-willing to attempt the extraction of cerium-144 from "fresh" spent nuclear fuel, 2–3 years old." [1]
Doesn't really sound plausible to me that a nuclear powered missile engine would, as far as I know, release a single radioactive isotope, Ruthenium 106 in this case, with its exhaust or upon a crash.
4 minutes is plenty enough time to validate the concept. And all these would "crash". Cruise missiles generally dont plan on landing. I wouldnt write this off so casually.
Does anyone have an educated guess on what the exhaust from this thing would consist of? Would it be spewing radiation, or mostly contained? Could it be safely stopped or cleanly destroyed after launch? Could the propulsion double as the payload?
"Sources said that the tests were ordered by senior Kremlin officials despite objections from the program's engineers, who voiced concerns that the system was still in its infancy.". Putin's press conference was on March 1st. The Russian presidential election was on March 18th. I think it's pretty clear that this was a marketing move.
The consensus was that it was a dumb idea, especially after ICBMs were deployed. Their only benefit vs alternatives -- incredibly long flight time (on the order of months / circling the globe 4.5 times) -- doesn't allow you to do anything you couldn't already do.
This was pre-stealth, but I can't imagine it's easy to stealth something with a red-hot exhaust (remember, to have endurance, it's superheating air rather than combusting limited fuel).
Hypersonic re-entry vehicles are far more useful, but also harder to develop.
Honestly, this seems a pretty blatant attempt to trot out Cold War era technology for a ra-ra "look, we're still relevant" showing than new R&D.
https://en.m.wikipedia.org/wiki/Project_Pluto
https://en.m.wikipedia.org/wiki/Supersonic_Low_Altitude_Miss...