The MER robots and the moon buggy are both off world rovers, but they are very different.  The Moon and Mars are different.  We can’t use the MER robots on the moon because they were made to handle the Mars atmosphere and the Mars environment.  It is like trying to play baseball with a hockey puck.  It just wouldn’t work.  They are both sports games involving a stick but  you need the right equipment for each game.  

 

The differences in the gravity, atmosphere, surface geology, and amount of sunlight make each place a unique experience.  Mars (34 to 160 million miles from Earth) is also a lot further away than the Moon (384,403 km/ 238,857 miles from Earth).  The Mars Exploration Rovers work on Mars because they were designed and equipped with just the right instruments to explore Mars.  The moon buggy was also designed just for exploration of the lunar surface.  One big difference is size.  The moon buggy is much larger than the MER robots and can travel farther and faster.

 

The rovers work perfectly for the environment they were made to explore because scientists simulated the conditions of the environment and did field tests to develop the navigation, communications, and instruments for each of them.  Field tests for the Mars rovers include Death Valley, CA and the Meteor Crater in Northern Arizona.