While the ghost has eluded detection (he comes out in October), there are still quite a few different secrets to be found! See what you can find and earn you and your fellow players more in-game rewards! Just post your screenshots to the community hub as you find them. If you find a silent space slug that hasn't been found already, you get to name it! The ones that have already been found say something if you bump into them or get near them. There are many other secrets still to be found too, here is a running list:
https://steamcommunity.com/app/857860/discussions/0/3108017414040352882/