From: Utopia Planitia Fleet Yards
From the FAQ:
Am I crazy or do the planets no longer orbit their stars?
--> I explained this a bit in the stream Q&A, but bottom line is that the the planets still rotate, but they no longer have animated orbits.
Partly this is due to the change in scale, the rest comes down to the difference between having things look ok in 2D where ships and stations moved through each other all the time vs. nice 3D where they need to avoid colliding, enter hangars and docking bays properly, exit construction yards, etc.
Having the orbits match up with the more realistic scale would have meant they would be slow enough that you likely wouldn't notice the movement easily, while at the same time any movement would create a lot more challenges for us in terms of the new 3D mechanism for docking of ships in spaceports and near planets and collision avoidance. We decided ultimately that it wasn't worth adding extremely slow orbits to create a huge amount of extra bugs and work to account for that when we could spend that limited time better elsewhere on other more noticeable features. It's not impossible that orbits may return at some future date, but it's not in the plans right now.
Thanks, well orbiting planets is indeed missing, I definitely agree.
Chancellor Gorkon to Captain James T. Kirk:
You don't trust me, do you? I don't blame you. If there is to be a brave new world, our generation is going to have the hardest time living in it.