(CNN)Here’s some background information about Mars exploration. The United States and the Soviet Union are the only two countries to land a spacecraft on Mars.
Facts:
There have been seven successful US Mars landings: Viking 1 and Viking 2 (both 1976), Pathfinder (1997), Spirit and Opportunity (both 2004), Phoenix (2008) and Curiosity (2012).
There have been seven successful US Mars landings: Viking 1 and Viking 2 (both 1976), Pathfinder (1997), Spirit and Opportunity (both 2004), Phoenix (2008) and Curiosity (2012).
The only other country to land a spacecraft on Mars was the Soviet Union in 1971 and 1973.
