Launch year / Name / Size / Comparison 2011 Curiosity 2.8 meters (Mini Cooper) 2003 Opportunity 1.7 meters (Go Kart) 2003 Spirit 1.7 meters (Go Kart) 1999 Pathfinder .75 meters (Microwave)
really big
Yes
Rock and traces of various gases, such as oxygen, nitrogen.
Two rovers of different kinds have landed on Mars. The first Mars Rover landed in 1997. The first Mars Navigator landedin 2004.