Congrats Solyaris! Nice game with a 1550 AD space victory. It would be nice to compare games if you are willing to share any details of your game.
re: space victories
I don't think space victories are at all the most common victory to go for in gotm. I enjoy playing space games because it feels more "complete" since it takes you through all of the technologies (or most of them).
A military victory at this level of difficulty would be quite quick I have to imagine.
Pre AD: Stonehenge, The great wall, Oracle (->CS), pyramids, MoM and TGL. Basicly had 1/2 central cities to build wonders while the other main city build settlers/workers. Delayed any building (library ect) untill post AD. My plan is always to get as many cities as possible, as propperly improved as possible before 200-300 AD. Its also important to understand that this map was "happy" limited, since all of your early cities could easily grow to 15+. This means that techs such as MC (forge +2), construction (ballpark +3) and pyramids (+3) increased alot in value.
@ 1 AD I had 15 cities, ~20 workers and research edu (done with music and philo.)
Post 1 AD its all about reaching MT ASAP. Edu -> nat -> gun -> MT (usualy lib. MT, but figrued it would be better to lib. biology). Then killed off America, Croatia (sitting bull) and 50% of Holland. Basicly tried to balance my area to 60-63%. Was done with this around 1050AD. Around 800-900AD I also stop making cottages and start building workshops/watermills.
Techs (post MT): chem. -> Scientific M. -> Lib (biology as free tech) -> Communism
Lean back, watch your backers skyrocket!
Watermills are btw very, very good post electricity/financial/golden age/communism. Instant 3F, 3P, 5C; almost better then a town.
Pretty sure I could have done 4-5 turns or so better if I had started my first chain golden age earlier. Wasted about 12 turns of my last golden age (@ it came after spaceship launch)