Atmospheric drag on satellites- especially how it changes with solar output levels- is a hard thing to model accurately, and a major contributor to orbital unce

Atmospheric drag on satellites- especially how it changes with solar output levels- is a hard thing to model accurately, and a major contributor to orbital uncertainty here on Earth. The Martian atmosphere is two orders of magnitude thinner, but it is far less than two orders of magnitude understood. And the level of our understanding matters for our ability to correct for it's perturbations. NASA is very good at sending spacecraft through regular space and hitting precise windows (MCO units issues aside), it's in orbit that things get more complicated, because now there are just a lot more potential interactions to deal with. We can use LOS on planetary occultations to give you some data, but it's still a lot of work to get from there to mascon maps, upper atmospheric data, etc.