Unless this mission can be shown to serve some necessary engineering proof-of-concept or demonstration role that no other can provide, it is an enormous boondoggle with nothing to recommend it. Even its PR and publicity value would quickly go negative if the mission failed, as can even the most routine space travel. It would only be worthwhile if it were some sort of rescue operation, like the Hubble Repair mission. Perhaps there is some other expensive and potentially value spacecraft out there out of action and potentially rescuable. But even then, just launching a new one may turn out cheaper than chasing down and fixing a broken one.

There's a lot of space junk out there that might be worthwhile recovering, but only because it poses a threat to future space exploration. Large objects with a good chance of undergoing collisions which would turn them into deadly clouds of shrapnel should be removed, kicked up into safer orbits, or sent into the atmosphere to burn up harmlessly. I don't think Vanguard I would be at the top of that list.