A timeline of Mars exploration

1960

USSR - Marsnik 1: Rocket failed

USSR - Marsnik 2: Rocket failed

1962

USSR - Sputnik 22: Exploded in Earth orbit during Cuban missile crisis; debris triggered U.S. early warning radar systems.

USSR – Mars 1: Radio failed at 65.9 million miles.

USSR – Sputnik 24: Achieved Earth orbit only.

1964

U.S. – Mariner 3: Cover of craft never detached from rocket.

U.S. – Mariner 4: First Mars success; returned 21 photos.

USSR – Zond 2: Radio and solar panel failed.

1969

USSR – Mars 1969A: Exploded on launch.

USSR – Mars 1969B: Exploded on launch.

U.S. – Mariner 6: Returned 75 photos.

U.S. – Mariner 7: Returned 126 photographs.

1971

U.S. – Mariner 8: Launch failed.

USSR – Kosmos 419: Failed to escape Earth orbit.

USSR – Mars 2: First man-made object on Mars; transmitted some orbital mapping data before crashing on surface.

USSR – Mars 3: Transmitted some orbital data and photos before lander was destroyed by massive Martian dust storm.

U.S. – Mariner 9: Transmitted 7,329 photos.

1973

USSR – Mars 4: Never achieved orbit but provided fly-by pictures and data. Microchip flaw prevented retro-rockets from firing to slow craft into orbit.

USSR – Mars 5: Lasted only 22 orbits; sent 60 images; craft pressurization lost.

USSR – Mars 6: Lander transmitted information during descent, but communications failed at moment of impact.

USSR – Mars 7: Microchip error caused lander/orbiter separation four hours early, missed planet.

1975

U.S. – Viking 1: First lander to successfully complete mission.

U.S. – Viking 2: Combined, the Viking orbiters and landers returned more than 50,000 photos.

1988

USSR – Phobos 1: Software error pointed solar panels away from the sun, power failed.

USSR – Phobos 2: Onboard computer failed.

1992

U.S. – Mars Observer: Fuel explosion sent orbiter off course.

1996

U.S. – Mars Global Surveyor: Conducted prime mission of science mapping until 2006.

Russia – Mars 96: Failed to reach Mars orbit; reentered Earth’s atmosphere and burned up.

U.S. – Mars Pathfinder: Lander (Sagan Memorial Station) and Sojourner rover sent thousands of images and other data.

1998

Japan – Nozomi (Planet-B): Navigation errors, electrical problem and power failures prevented craft from entering close Mars orbit.

U.S. – Mars Climate Orbiter: Orbit too low, burned up in Martian atmosphere.

1999

U.S. – Mars Polar Lander/Deep Space 2: Software error caused retrorockets to turn off, causing lander to crash on Martian surface. Two probes also failed to communicate after impact.

2001

U.S. – Mars Odyssey: Currently conducting prime mission of science mapping and serving as information relay for current and future Mars missions.

2003

European Space Agency – Mars Express/Beagle 2: The Mars Express orbiter conducted extensive imaging of Mars’ surface and mapping of mineral composition and relays information from current and future Mars missions. Beagle lander communications failed on impact.

U.S. – Spirit Rover (MER-A): Conducted geological research and imaging for five years before getting trapped in soft sand and losing communications.

U.S. – Opportunity (MER-B): Continues to search for clues to past water activity and conduct geological research.

2005

U.S. – Mars Reconnaissance Orbiter: Continues to map future landing sites, study Martian weather and climate, and relay information for current and future Mars missions. Has returned more data than all other missions combined.

2007

U.S. – Phoenix Mars Lander: Studied northern polar climate and weather until it was destroyed by harsh Martian winter.

2011

China and Russia – Phobos Grunt/Yinghuo-1: Joint mission involving Martian moon lander and Mars orbiter failed to escape Earth orbit. Burned up in atmosphere with fragments landing in Pacific Ocean.

U.S. – Curiosity rover: To arrive Aug. 5 at 10:31 p.m. PDT.

2013

U.S. – Mars Atmosphere and Volatile Evolution Mission (MAVEN): Will explore the planet’s upper atmosphere.

Sources: NASA; Times reporting