No supports needed.  6 M3 screws at least 30 mm long needed. Print the planet carrier first. Print the 40 tooth ring and planets together, do not separate them,  as each planet is different. Lock the planet positions using M3 screws to planet carrier as shown on the picture. Then place the ring 41 last. If planets and 41 ring are fused together tinker with shell/horizontal expansion parameter of your slicer. Some refinement of the planet gears holes needed to make them rotate smoothly on M3 screws,  after some run in they will be much smoother. you can print the planet carrier 2 times to clamp everything together, but using planet carrier only on 1 side displays the planet/ring interactions best.