Question: when did we first put a rover on mars?
Answer: January 2004

In January 2004, the NASA twin Mars Exploration Rovers named Spirit (MER-A) and Opportunity (MER-B) landed on the surface of Mars.  Both have met or exceeded all their targets. Among the most significant scientific returns has been conclusive evidence that liquid water existed at some time in the past at both landing sites. Martian dust devils and windstorms have occasionally cleaned both rovers' solar panels, and thus increased their lifespan. Spirit Rover (MER-A) was active until 2010, when it stopped sending data because it had fallen into a sand dune.