The screenplay wasn't particularly different in any way and didn't need to be set on Mars, except for the tin can on wheels I suppose, and I bet it was shot on Earth anyway.
Unfortunately, the nature of the beast (the screenplay) meant that Helen Mirren didn't really have any say until well into proceedings. Jessica was fine but the story whilst she was at the helm couldn't steer a straight course and got distracted.
Although the material is light to its credit it is not too mawkish. The screenplay touches bucket list territory but I'm surprised it didn't get more mileage (or French kms) out of the Omar character's family to add a bit more substance to proceedings.
Based on a Le Carre novel it therefore needs concentration. Hoffman's accent was annoying and I don't see how this kind of falseness can be seen as a positive for anyone or anything.