Fusion bomb is technologically hard problem even today. Fission is simple but required a of the material which can only be produced by technologically hard devi

Fusion bomb is technologically hard problem even today. Fission is simple but required a of the material which can only be produced by technologically hard devices. This gates it for now. But even today we can see that countries wishing to destabilize neighbors can simply gift complete assembly to their allies. Like russia did with North Korea, and is now probably doing with Iran. So ownership of the tech by large political entities doesn't matter if one of such entities decides to defect and abandon common rules. So, yes, there won't be some independent spacer terror cell. But what if one of the space faring countries will decide to simply sponsor some Hamas 2.0 to attack their opponents? Considering that this will be a new age of conquest possibly, where nothing in the Solar System is yet owned by anyone and there will be a lot of takers. Like a simplest question - who's are Luna and Mars? :) Next issue is that chemical rockets are much simpler and cheaper, also they are not gated by any tech or material. Sure, there are important secrets around nozzles and stuff, but I suppose a simple crude rocket will work just fine. So assuming we are at the level when humans can travel to the asteroids to mine them (also a big if, due to it being economically unfeasible) they can setup such a kamikaze rocket. Attack will be from outside of the ecliptic plane, so likely undetected. Attack can be scaled to more than one rock, so that every single point of failure, every dome etc must have dozens of anti-spacecraft level defense rockets (nukes most likely). It is not feasible. Of course all of this is about far far future, we can't predict what will happen.