@war_killer: Well that's the entire point of the position, he'll be sneaking around alien civilizations and stuff.
True, but even then he's still a complete unknown in space. On Earth people knew him as Cap's sidekick during WWII, having step in as Captain America, and his past as the Winter Soldier being made public. But out in space, those worlds wouldn't really give a crap about any of that...to most alien civilizations Earth and humanity are just lower life forms and beneath them...so I don't see why Bucky would have to be as covert out there seeing as it's not like people are going to even give a second thought about some random human.
Because if they know who he is then they know where to find find him. And if they find out an earth man is assassinating people then that means war for earth.