At the moment, it always says "Our radar detected a new UFO near [base]". I think it would be nice if the UFO number the game assigns to it was shown in brackets here, since UFOs that you have seen before do get their old number back. That way, you could check back and verify whether you've seen that particular UFO before or not.
Also, maybe it should say "Our radar reacquired a previously detected UFO near [base]" instead when you've already seen that UFO.
