The first one's rather easy apoapsis roughly translates to... wait for the surprise... apoapsis! Oh boy, that was a hard one. The other one is "Du wirst heute nicht in den (Welt-)Raum gehen." I actually have this problem in both ways, I'm a native German speaker but am around English vocabulary in my workplace very much. I'm a computer scientist... Well, engineer would be the better term, but anyways, I develop simulation systems. So sometimes I know the exact expression in English for something but I can't think of a German counterpart that would actually say the same without saying one to three sentences. But for orbital stuff I think mostly it's the same words, Apoapsis, Periapsis, Impuls(e) and stuff like that... I think that stems from the fact that most of these words are derived from Latin or some old Greek or something like that. And when in doubt and speaking with someone who doesn't know crap about the topic just pronounce the English words like you would in your native language and impress them with that...