In radio, talking over the start of a song and ending right when the lyrics kick in is called "hitting the post" and sometimes it's done without prewritten copy, just winging it.
It's just a skill you can practice and some people get quite good at it.
One difference with this is if you miss the lyrics, you can just try again next time. There's a new song every few minutes.
There was only ever one launch of Voyager 2.