As far as I am aware, Advanced Rocketry planets have they own specific biome, hence why Terraforming is an option, for example Mars is red, the Moon is grey-white, but I've been playing ATM3 for a while now, I've invested a LOT of time in AdvancedRocketry only to find that all the planets are generic clones of the Overworld because AbyssalCraft and Biomes'O'Plenty have replaced the biomes with the same ones you find on 'Earth', this kinda kills the game for me, I know there's plenty of mods to play but AdvancedRocketry is my main drive and since Planets won't generate their own style it just drains all the fun out of it.

a lot of work went into defining custom planets, but the conflict might still be biting us and we need to tweak some more

duplicate of #362

Should be fixed in 5.9.3 that will release in the next few days depending on testing.