This is my model of NASA's Sojourner rover, which explored the Martian surface in 1997 and 1998. Oddly, the lander (Pathfinder) which deployed the rover and and relayed all transmissions fell silent the exact moment I turned 7 years old (6:19 PM, February 27, 1998).
Anyway, I think this one of my better models. I spent a long time on the wheel connections. Also the APXS (alpha-proton x-ray spectrometer [a tool for analysing the composition of soil and rocks]) was a little difficult; I wanted it to be able to extend; for a while I experimented with pneumatics, until choosing the connections used on the arms of the big old lego people (scala, isn't it?). Please write a review!