There also have been several failed missions to Mars:
In 1964, NASAs Mariner 3 was launched from Cape Canaveral Air Force Station. In space, its solar panels failed to open and the batteries went flat. Now its orbiting the Sun, dead. In 1965, Russian controllers lost contact with Zond 2 after it lost one of its solar panels. It lifelessly floated past Mars in the August of that year, only 1,500 km away from the planet. In March and April, 1969, the twin probes in the Soviet Mars 1969 program both suffered launch failure, 1969A exploded minutes after launch and 1969B took a U-turn and crashed to earth. More recently, NASAs Mars Climate Orbiter crashed into the Red Planet in 1999 after an embarrassing measurement unit mix-up caused the satellite to enter the atmosphere too low. On Christmas 2003, the world waited for a signal from the UK Mars lander, Beagle 2, after it separated from ESAs Mars Express. To this day, theres been no word.
Reference: Mars failed missions (link).