A laser defense weapon, coupled with the black titanium skin, likely already close to its thermal limits, might produce results of interest to a defender.
In the meantime, its going to take a lot of time and money to develop those weapons as well. I mean, you're talking about hypothetical countermeasures that don't even exist as a solid concept yet.
I wonder if satellites and newer weapons wouldn't be able to intercept its flight path by then.
You probably wouldn't have to match its speed to bring it down, just throw up a cloud of junk in its way.