I don't think it's plausible to think that they a) adlibbed it, nor b) wrote the speech themselves and revealed their true location by mistake
Now that we both understand my A) B) C) questions, can you answer what you think would be the most plausible answer?
"Right now we only can fly in earth orbit, that's the farthest we can go, and this new system that we are building is gonna allow us to go beyond and hopefully take humans into the solarsystem to explore, so the moon, mars, asteroids, there's a lot of destinations that we could go to, and we're building these building-block components in order to allow us to do that eventually"
He's saying that RIGHT NOW they can only fly in earth orbit. They don't have a program/technology to, for instance go to the moon. This doesn't mean that he's saying that they never could go to the moon.
Example: Right now I can't go into town to the supermarket because I don't have my car. This does not mean that I wasn't able to go last week too (I could, because I had my car)
Same with when he's saying that eventually they will, this doesn't rule out that they went before.
Example: Eventually I will be able to go to the supermarket because I will get my car. This does not mean that I've never been able to go
I've posted explanations to this at least twice before, the explanation to why NASA can say that they don't have the technology to go to the moon right now. Here they are again:-