Lunokhod (Russian: Луноход, "Moonwalker") was a series of Soviet robotic lunar rovers designed to land on the Moon between 1969 and 1977. The 1969 Lunokhod 1A was destroyed during launch, the 1970 Lunokhod 1 and the 1973 Lunokhod 2 landed on the moon and the 1977 Lunokhod was never launched. The Lunokhods were primarily designed to support the Soviet manned moon missions and to be used as automatic remote-controlled robots to explore the surface and return pictures. The Lunokhods were transported to the lunar surface by Luna spacecraft, which were launched by Proton rockets. The moon lander part of the Luna spacecraft for Lunokhods were similar to the ones for sample return missions. Not until the 1997 Mars Pathfinder was another remote-controlled vehicle put on an extraterrestrial body.
During its 322 Earth days of operations, Lunokhod 1 traveled 10.5 km and returned more than 20,000 TV images and 206 high-resolution panoramas. In addition, it performed twenty-five soil analyses with its RIFMA x-ray fluorescence spectrometer and used its penetrometer at 500 different locations.
Lunokhod 2 operated for about 4 months, covered 37 km (23 miles) of terrain, including hilly upland areas and rilles, and currently holds the record for the longest distance of surface travel of any extraterrestrial vehicle. It sent back 86 panoramic images and over 80,000 TV pictures. Many mechanical tests of the surface, laser ranging measurements, and other experiments were completed during this time.
For comparison, the similarly sized NASA Mars Exploration Rovers, Spirit and Opportunity had, by their fifth anniversary in January 2009, traveled a total of 21 km (13 mi) and transmitted over 125,000 images.
According to a French documentary TV film "Tank on the Moon" by Jean Afanassieff, the Lunokhod design returned to limelight 15 years later due to the Chernobyl nuclear power plant disaster. The East German made remote controlled bulldozers available to Soviet civil defense troops weighed dozens of tons. Too heavy to operate on the remaining parts of the partially collapsed reactor building roof. Human laborers could not be employed effectively to shovel debris, since work shifts were limited to 90 second intervals due to intense ionizing radiation.
Lunokhod designers were called back from retirement, and in two weeks rovers used nuclear decay heat sources for internal rack climate control, their electronic systems were already hardened to resist radiation. This benefit allowed the 1986 designers to quickly devise a derived vehicle type for nuclear disaster recovery work. Eventually two rovers were delivered to the Chernobyl accident zone and proved useful for clearing debris, earning awards for the designers. Due to extremely high radiation levels, all rovers eventually failed, and human workers (later named liquidators) were called in.