Mars Surface

Exploration
Dozens of spacecraft, including orbiters, landers, and rovers, have been sent to Mars by the Soviet Union, the United States, Europe, and Japan to study the planet's surface, climate, and geology. As of 2008, the price of transporting material from the surface of Earth to the surface of Mars is approximately US$309,000 per kilogram.
Active probes at the Martian system as of 2011 include the Mars Reconnaissance Orbiter (since 2006), Mars Express (since 2003), 2001 Mars Odyssey (since 2001), and on the surface, Opportunity Rover (since 2004). More recently concluded missions include Mars Global Surveyor (1997-2006) and Spirit Rover (2004-2010).