Greek Gods? You are asking if Zeus, Apollo, Hermes, Aphrodite, Poseidon and all of them are Astronauts? Seriously?
Think s/he meant Aliens............................... lmao. It's just........ idk. hilariously hilarious.
This is actually an old Star Trek thing. In Star Trek, our first "official" contact was with the Vulcans. However, many years prior, we had two contacts that were unofficial. The first was when a race of humanoid aliens helped populate a ton of planets with their DNA, giving Klingons, Vulcans, Humans, Cardassians, and thousands of other species a common bond. The second was when Greece and Rome were at the height of their power. According to the Trek timeline, a spaceship crash landed on earth. As the Federation wasn't in existence then, there was no Prime Directive to stop the aliens from messing with the more primitive Humans. Thus, with the technological advantages this race had over us, it made them seem like gods.