Nasa wanted to send a bigger and heavier rover to Mars. And the questions was... how to get it safely down.
Given the limitations with the thin atmosphere, the heavy rover, the need to avoid kicking up dust... they came up with a... solution.
This is the kind of Stuff Nasa and JPL are good at.
Impressive if it works. And meshes with my current reading material. Man so glad I picked up my copy for free.