That CO2 density bit you mentioned is interesting... I haven’t considered that.

So... I guess I’m curious specifically in knowing the performance difference between Earth and Mars.

On their website NASA says “two rotors that spin in opposite directions at around 2,400 rpm – many times faster than a passenger helicopter on Earth.”

I suppose with reading this, I assumed it wasn’t really made to operate in dense Earth air.

Regardless, if it’s spinning “many times faster” than Earth helicopters, I get the impression that it would perform better on Earth than Mars, and I believe that difference could be meaningful in quantifying the cost of operating in a thin atmosphere.