My first impression was that this looks like an old Mac game. Macs came out 1-20 years after the space race, depending on whether you count the start or finish. So the 'retro' look didn't really work for me even though it is implemented fantastically well. Full disclosure - I have never liked Macs so maybe a bit of bias going on here.
There is so much detail here that I found it totally overwhelming. I parked the game for a couple of days and am playing it now as it's one of the last ones I have left to rate.
It's like being made head of NASA with no prior experience and being asked to micro-manage the entire space program.