So I got my mum playing this to give me some resources in the PC game, then I got into playing it myself. We're at about the same amount of progress, with 3 galaxies unlocked so far. I have all the drones. Mum, however, is missing the gold / vertical drone.

Is it really so random that you may never get it or take ages to get it? It seems to me the vertical drone starts to become more necessary in the harder levels so I feel sorry for my mum to not have it available.

I suggested she tried going back to do the question-mark asteroids in the Stardust galaxy - I mean, doing ones she's already done, in case it gives her another chance to receive the yellow drone. But I can't shake the niggling doubt that maybe once you've done a question mark asteroid once, you don't get another chance at discovering something by doing it again.

Any help appreciated.