14 DAY TRIAL // The Mars missions started with the wrong foot in the early 1960s with six failures, five by the USSR and one by the US - the crafts didn't even manage to leave Earth's orbit and many exploded at launch. The first successful mission to Mars was NASA's Mariner 4 in 1964. This mission sent back to Earth 21 pictures. After another string of USSR failures, followed the successful Mariner 5 and then 6 in 1969 which returned 75 and 126 images.
Encouraged by its failures, USSR decided to aim at a more difficult target: actually landing a craft on Mars' surface. After three more failures, they finally did it in 1971. They were the first to do it. Mars 3 Orbiter/Lander was functional in orbit for 8 months sending interesting data and the craft landed safely on the planet's surface, but for some reason it only sent 20 seconds of data.
After several years of mixed results, including the successful US Mariner 9 (which returned 7,329 images) and the USSR's Mars 5 (which returned 60 images in its short 9 days adventure around Mars), the US successfully landed the Viking 1 and 2 in 1975. These returned more than 15 hundred pictures, made atmospheric measurements and the landers conducted soil experiments. These were the first direct evidences that Mars is a dead, waterless and incredibly cold desert.
The next successful mission was NASA's Mars Global Surveyor launched 11 years later in 1996. This orbiter has sent the largest amount of pictures and data and has been working for the past ten years.
Japan tried its chances in 1998 but the Nozomi craft unfortunately failed to enter Mars' orbit. The European Space Agency sent a very successful orbiter in 2003, the Mars Express Orbiter, but the Beagle 2 lander that went with that orbiter crashed on the planet.
Other US successes include Mars Pathfinder rover which has lasted until 2001, 5 years beyond its warranty and returned 2.3 billion bits of information, Mars Odyssey which sends high resolution pictures and of course the Mars rovers Spirit and Oportunity. Among the failures are the Mars Climate Orbiter (burned into the atmosphere), Mars Polar Lander and the Deep Space 2 Probes (communication failure) in the late 1990s all of which failed to enter Mars' orbit properly.
Although there have been more failures than successful missions to Mars, the trend is definitely encouraging. While in the early 1960s the crafts often didn't even exit Earth's orbit and in the 1970s some actually missed the red planet (!), now successes seem to be within reach more often.
Here's a statistic of the reasons why the missions to Mars have failed:
Failed to get off the ground: 4 times (USSR: 3, US: 1) Failed to reach Earth's orbit: 3 times (USSR: 2, US: 1) Reached Earth's orbit but couldn't escape from it: 3 times (USSR) Didn't reach Mars because the craft missed the planet: 2 times (USSR) Ran out of fuel: 1 time (Japan) Communication failure: 6 times (USSR: 5, US: 1) Burned into Mars' atmosphere instead of entering a stable orbit: 1 time (US) Crashed on the planet: 4 times (USSR: 2, US: 1, Europe: 1)
