Mars Surface

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).
Roughly two-thirds of all spacecraft destined for Mars have failed in one manner or another before completing or even beginning their missions, including the difficult late 20th century period of early pioneers and first-timers. In the 21st century failures are much less common. Mission failures are typically ascribed to technical problems, such as failed or lost communications or design errors, often due to inadequate funding or incompetence for a given mission. Such failures have given rise to a satirical counter-culture blaming the failures on an Earth-Mars "Bermuda Triangle", a Mars "Curse", or the "Great Galactic Ghoul" that feeds on Martian spacecraft. Some of the latest failures include Beagle 2 (2003), Mars Climate Orbiter (1999), and Mars 96 (1996).
• Past missions
The first successful fly-by of Mars was on July 14–15, 1965, by NASA's Mariner 4. On November 14, 1971 Mariner 9 became the first space probe to orbit another planet when it entered into orbit around Mars. The first objects to successfully land on the surface were two Soviet probes: Mars 2 on November 27 and Mars 3 on December 2, 1971, but both ceased communicating within seconds of landing. The 1975 NASA launches of the Viking program consisted of two orbiters, each having a lander; both landers successfully touched down in 1976. Viking 1 remained operational for six years, Viking 2 for three. The Viking landers relayed color panoramas of Mars and the orbiters mapped the surface so well that the images remain in use.