Ukraine does have "Smerch" rockets - the engine part is about 500kg, 6m length, 0.3m diameter. In the dumb version it carries 280kg payload to 70km. The high-pr

Ukraine does have "Smerch" rockets - the engine part is about 500kg, 6m length, 0.3m diameter. In the dumb version it carries 280kg payload to 70km. The high-precision version carries 170kg to 120km. You can decrease payload further - to about 60kg - and hit the bridge (not that 60kg would destroy it, yet given the cheapness and availability of the rocket, one can use it to say regularly hit military cargo trains and trucks on the bridge while also damaging the rails/pavement for several hours in a row, and also one can use it to attack the S-400 defending the bridge, etc.) I think what Ukraine hits, be it with own or Western weaponry, isn't just the matter of capability. I think they are trying to be very careful to not trigger nuclear response (my personal opinion is that this fear is overblown - of course i have this opinion while sitting comfortably in an armchair in CA). Also i think they are trying to not scare the Western partners as a country which, just to name a few, was the powerhouse of the USSR space and ICBM programs and has several working plutonium producing nuclear stations, and thus definitely has very interesting options of its own strategic defense.