That means that Russia has an interest in getting back these areas. Or at least having this area of the Ukraine in its sphere of influence.
[Also it just so happens that Russia can't build the super aircraft carrier they were planing on without the Ukraine. There is no dry dock. This all goes to show that Russia has to do serious rebooting of their industry unless they can get back the Ukraine.] The reason the weapons and space industry was divided up in this way was Stalin. As was explained to me (by a grandson of his) that by dividing up these major industries in this way he was assured that the USSR could not break up--because if it did, then each part would have factories that produced only one part of a car or an airplane which was useless without the other parts.
In any case, this was no problem until recently. The Ukraine simply made the parts, and sent them off to Russia. This has stopped recently, and this is the reason Russia is now looking to redo its military and space production industries.
In any case, it would seem the Russians feel they are just taking back what belongs to them. I think it is understandable that the Ukrainains don't feel the same way.
Certainly most of the infrastructure of the Ukraine was built by Russians. This really is one people.
Or maybe just let those two republics go over to Russia? Why fight about borders that have been fluid anyway over the centuries? If they want to be part of Russia, fine let them!