(CNN) — Here’s a look at the exploration of Mars. The United States, Soviet Union and China are the only three countries to land a spacecraft on Mars. There have been nine successful US Mars landings: ...

Mars has captured human imagination for centuries, but the Red Planet holds far more secrets than NASA typically shares with the public. While the space agency presents Mars as a fascinating but ...

(CNN) — Here’s a look at the exploration of Mars. The United States, Soviet Union and China are the only three countries to land a spacecraft on Mars. Facts There have been nine successful US Mars ...

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 ...