Luna 21

Mission

Luna 21 launched on January 8, 1973, just weeks after the final Apollo moon landing. A Proton-K/D rocket boosted it into an Earth parking orbit, then sent it toward the Moon. On January 12, the spacecraft entered a 90 by 100 kilometer lunar orbit tilted at 60 degrees. Over the next two days, its lowest point dropped to 16 kilometers. After 40 orbits, on January 15, the braking engine fired at that altitude, sending the craft into free fall. At 750 meters above the surface, the main thrusters engaged, slowing the descent until 22 meters, when they shut off and secondary thrusters took over. The engine cut out at 1.5 meters, and the lander touched down at 23:35 UT inside Le Monnier crater, at coordinates 25.85 degrees north and 30.45 degrees east, between the Sea of Serenity and the Taurus Mountains. Onboard was a bas-relief of Vladimir Lenin and the Soviet coat of arms.

Less than three hours later, at 01:14 UT on January 16, the rover rolled off the lander. This 840-kilogram vehicle, named Lunokhod 2, was an upgraded model with a third TV camera, better eight-wheel traction, and extra scientific gear. By the end of its first lunar day, it had already covered more ground than its predecessor, Lunokhod 1, did in its entire mission. On May 9, the rover accidentally drove into a crater, and dust coated its solar panels and radiators, upsetting its internal temperature. Efforts to rescue it failed, and on June 3, the Soviet news agency declared the mission over. Before contact was lost, Lunokhod 2 had captured 80,000 TV images and 86 panoramic photos, and conducted hundreds of soil surveys, both mechanical and chemical.

The Soviets later disclosed that during a planetary exploration conference in Moscow from January 29 to February 2, 1973—after Luna 21 had landed—an American scientist gave photos of the landing site to the Soviet engineer leading the Lunokhod 2 mission. Those images, taken before the Apollo 17 landing, helped the rover’s driver team navigate the Moon.