Ah! right.. best place to hide a space ship is the backside of the moon, with a light covering of lunar regolith. Nice and handy for access, no maps of the far side until 20th century so no chance of anyone noticing a discrepancy, so you could park in in a crater and cover it over and no-one would know it's there, it's just another bolder field in the middle of the lunar scape. You could even hide access hatches as smaller craters with a bit of paint.