An error occurred while saving the commentAnonymous commented
You can already do this.
1 design your spacecraft
2 add a docking port where you want your rover to be
3 design your rover and dock it with your spacecraft by either building an infrastructure with wheels and struts so you can dock it before you leave smearth, or dock in orbit.
I did a mission to mars and I used 3 command module's one was my spaceship I used for orbiting returning to earth etc. Another was a Lander that I used to land on mars and return to orbit. And the last one was a rover that I brought to mars docked to my Lander and undocked once I landed.