Sojourner Mars Rover

This model of the Sojourner Mars rover is ½ scale.  The model can either use motors/stepper motors to drive the rover with a joystick or as a static model.  To drive the motors an Arduino Uno is used to take inputs from the joystick and drive the various motors.  Note: The scale size servo motors I chose to use work fine on the workbench but are not powerful enough to turn the wheels with the weight of the rover.  

To make the model look as realistic as possible with minimal gluing and best results the technique of changing the filament partway through printing is used.  This is mainly used on the solar panel which has a white base followed by a single layer of copper (or similar color) and then a single layer of black.  It is suggested to try a small test print first to verify the technique before printing the entire part (see pictures).   This technique is also used on other smaller parts such as the rotation sensors.

Another multi-color technique is used to print the one center wheel tread with a black and white strip running down the middle.  This technique is described in the install guide.  The three parts of different colors are printed one on top of the other.  Since the black and white parts are only two layers high they do not conflict with the printing of the other parts.  Since the Prusa slicer has a very good elephant compensation you should turn off this compensation for these prints so the parts stick together.  With the Prusa printer (and possibly others) you need to know where the printer checks bed height and print the black and white stripe in an area of the bed where print bed height is not checked, which is usually just off the center axis.  When you are done you will have a single part made from three different colors ready to glue onto the wheel.  

A bit of trivia... The Sojourner was named after a famous black slave woman named Sojourner Truth.  The center wheel with the black and white stripe is a wheel abrasion experiment.  Since NASA doubles up on everything an exact duplicate was created and named Marie Curie which now resides at the Smithsonian Air and Space Museum.