While searching for references on Curiosity’s rocker-bogie suspension geometry, I came across a high-resolution CAD rendering of JPL’s upcoming Mars 2020 rover. It was a useful reference for suspension geometry as it is largely identical to Curiosity’s suspension. But there’s one very interesting change: the wheel design was noticeably different for Mars 2020.
Curiosity suffered wheel damage in its travels and it’s no surprise JPL took the lessons learned and equipped their follow-up rover with a different wheel design. Aside from lessons about reliability, there are also changes made to better match the terrain this rover expects to see in its mission area. Here on Earth our cars have different tires for different environments, so a Mars rover similarly gets wheels tailored to its mission.
Performance requirements are not nearly as stringent for an earthbound rover model, so we have the freedom to adopt either design based on preference. I decided to try printing a wheel inspired by Mars 2020 rover wheel design and see how it looks.
These wheels still have the same six spokes as Curiosity wheels, each a piece of titanium curved in a way that’s not easy to duplicate in 3D printed plastic, but we can still take inspiration. The article linked above mentioned the wheel proportions are slightly different, they didn’t provide exact numbers. So we kept the spokes and the proportions and changed the wheel grousers, which are gently curved instead of zig-zagged and there are twice as many of them. (24 vs 48.)
Once printed, we can compare the wheels side by side. Curiosity-inspired design on the left, Mars 2020-inspired design on the right. I took it around for feedback from other members of SGVHAK and the response overwhelmingly favors the new Mars 2020 inspired design. So that’s what Sawppy and Rover will roll on!