A Lunokhod 2 model from “Russia in Space” exhibition (Airport of Frankfurt, Germany, 2002). Image: Wikipedia
Soviet Union’s Luna 21 spacecraft landed on the Moon and deployed the second Soviet lunar rover, Lunokhod 2, in January 1973.
The rover stood 135 cm high and had a mass of 840 kg. It was about 170 cm long and 160 cm wide and had 8 wheels, each with an independent suspension, motor, and brake. The rover had two speeds, ~1 km/h and ~2 km/h.
Lunokhod 2 was equipped with three TV cameras, one mounted high on the rover for navigation, which could return high-resolution images at different rates (3.2, 5.7, 10.9 or 21.1 seconds per frame). These images were used by a five-man team of controllers on Earth who sent driving commands to the rover in real time.
Power was supplied by a solar panel on the inside of a round hinged lid which covered the instrument bay, which would charge the batteries when opened. A polonium-210 isotopic heat source was used to keep the rover warm during the lunar nights. There were 4 panoramic cameras mounted on the rover.
Scientific instruments included a soil mechanics tester, solar X-ray experiment, an astrophotometer to measure visible and UV light levels, a magnetometer deployed in front of the rover on the end of a 2.5 m boom, a radiometer, a photodetector (Rubin-1) for laser detection experiments, and a French-supplied laser corner-reflector. The lander and rover together weighed 1814 kg.
Lunokhod 2 operated for about 4 months, covered 37 km of terrain including hilly upland areas and rilles and 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.
On June 4 it was announced that the program was completed, leading to speculation that the vehicle probably failed in mid-May or could not be revived after the lunar night of May-June.
The Lunokhod laser retroreflector is still used by Earth-based stations for laser ranging, Lunokhod 2 is located at 25.8323 N, 30.9221 E.