there are 6 of these wheels on each rover on Mars! It was programed with GIBBSCAM I tried to make this wheel a bit too small and have been gradually getting bigger. It should be quite a desk top conversation piece!! Some of the detail is really small in the inner bottom side. Original wheel is a little over 10" across. a little less than 50 percent size might work well. Let me know what you think. I just got a new model that has less smaller detail on sides. I am running this new file right now