Planets. The only problem is there is nothing rewarding about going to planets other than you've been there. I made this post for what you guys think of this. Although, I personally think that adding food to the game would be awesome, it could be about efficiency as well. Like better soil performs better. This means farming on planets could be more efficient as well, attracting players to build large farms on planets. Earth should always make fruits, vegetables and grains grow 100% produce due to right temperatures, making it a good idea to stay here on Earth. Mars, this planets soil, could, be used to create fresh martian soil that has a efficiency of 75%. Alien planet could also create a new type of soil that could only grow unique, extraterrestrial vegetables at a high 175% efficiency. I think in space the plants should grow at a low 35% efficiency. This is because of climates and natural gravity. Although, in moons it is slightly higher, at 45%. I hope this idea could help space engineers in the future! (Soz for reposting comment!)