Moonwalker: The Soviet Lunokhod Program

Lunokhod was a series of Soviet robotic rovers that landed and explored the moon in the early 1970s. The name is Russian for "moonwalker" and the program operated concurrently with the Zond and Luna programs. Zond flew uncrewed circumlunar missions while Luna, mistakenly called "Lunik" in the West, consisted of lunar robotic spacecraft missions.

Artwork depicting Luna landing on the moon and deploying Lunokhod (NASA)

The rovers were initially designed to support crewed Soviet lunar missions. In the original plans, two Lunokhod rovers would be sent to the moon to survey the landing site on an LK-R uncrewed lander a few weeks before cosmonauts would arrive in their own LK lander. The LK-R would serve as a rescue craft should the LK fail. Later crewed versions of Lunokhod would have been equipped with oxygen, standing pads, and manual control for the cosmonaut. This future concept is the root of legends surrounding cosmonauts driving Lunokhod's 1 and 2 and taking part in suicide missions. The fact is these rovers were too small and the Soviet Union never would have even acknowledged their existence if knowledge of such missions was detrimental to its international image. Instead, they were used only for surface exploration and photography after the American crewed Apollo landings caused the cancellation of the Soviet manned lunar program.

The Lunokhod rovers were designed by Alexander Kemurdzhian at Lavochkin, a Russian aerospace company and major participant in the Russian space program. They were 4.5 feet (1.35 m) high, 5'7" (1.7 m) long, and 4'11" (1.6 m) wide. They had only two operating speeds, approximately 0.6 and 1.2 miles per hour (1 and 2 km/h), and eight wheels. The rovers were able to work in a vacuum because they used a special fluoride-based lubricant for their mechanical parts. Each wheel hub had electrical motors enclosed in pressure containers. They drove across the moon during the day and used solar panels to recharge their batteries. At night, they went into hibernation mode and were heated by a radioisotope heater unit. The rovers were equipped with a cone shaped antenna, a helical antenna, four TV cameras, and special devices to take samples of lunar soil as well as an x-ray spectrometer, an x-ray telescope, a cosmic ray detector, and a laser device. The Lunokhod's were transported to the surface by a Luna spacecraft and were launched by Proton-K rockets.

Lunokhod Rover (dkfindout.com)

A lunodrom, or moondrome, was built in the village of Shkolnoye in 1968. It was used to study and solve issues with the Lunokhod rovers' framework and train cosmonauts for lunar EVAs. It covered more than 9,842 cubic feet (3,000 cubic meters) and included 54 craters and around 160 rocks of varying sizes. The facility was located not too far from the tracking facility that supported all Soviet lunar programs in the closed town Simferopol-28. The first rover, Lunokhod 1A, was destroyed during launch on February 19, 1969. This event was not made public until years later and resulted in polonium 210, a radioactive heat source, being spread over a large region of Russia.

Lunokhod 1, the first true Lunokhod rover, launched on November 10, 1970 and was the first roving remote-controlled robot to land on a celestial body. Luna 17 carried and landed the rover on the moon. They entered lunar orbit on the 15th and soft landed in the Sea of Rains on the 17th. Luna had dual ramps so the rover could easily roll down to the surface. Lunokhod 1 operated for 322 days and traveled 6.5 miles (10.5 km), taking more than 20,000 television images and 206 high-resolution panoramas. It also performed 25 soil analyses.

Lunokhod 1 before launch (NASA)

Lunokhod 2 launched with Luna 21 on January 8, 1973 and entered lunar orbit on the 12th before landing in the Le Monnier crater on January 15. This rover was more advanced than the first and some of its primary objectives included surface photography, studying light levels to determine the practicality of astronomical observations from the moon, and studying the mechanical properties of lunar regolith. Lunokhod 2 took pictures of Luna 21 and their landing site after rolling down the lander's ramp to the surface. The rover operated for about four months and covered 26 miles (42 km), including hills and rilles [1]. It took more than 80,000 pictures and 86 panoramas and held the record for longest distance of surface traveled by a vehicle on an extraterrestrial body until 2014.

Lunokhod 2's picture of Luna 21 (NASA)

Lunokhod 3 was planned for 1977 with Luna 25 but did not launch due to lack of launch vehicles accessible and funding. It is now on display at the NPO Lavochkin museum.

Two more Lunokhod rovers were built in the 1980s, not for any sort of space exploration, but as a result of the Chernobyl nuclear power plant disaster. The East German-built remote controlled bulldozers the cleanup team were using were too heavy to operate on the partially collapsed reactor building roof. Lunokhod designers were brought out of retirement and two weeks later, two new rovers called STR-1 were complete. The rovers were a natural choice for nuclear disaster recovery work because they already used nuclear decay as a heat source. They were delivered to Chernobyl on July 15, 1986 and cleaned up some of the accident before failing due to extremely high radiation levels.

STR-1 at Chernobyl (rovercompany.ru)

Fifty years later, Lunokhod 1 and Lunokhod 2 remain dormant on the lunar surface. Ownership of Lunokhod 2 and Luna 21, however, was sold by the Lavochkin Association at a Sotheby's auction in New York in December 1993. Richard Garriott, private astronaut and son of Skylab and Space Shuttle astronaut Owen Garriott, purchased the rover and lander for $68,500. He remains to this day the only private owner of an object on a celestial body [2]. After Lunokhod 2 the next remote-controlled vehicle put on a planetary body was Mars Pathfinder in 1997. NASA's Lunar Reconnaissance Orbiter photographed Lunokhod 1's tracks and final resting place.

Author's note: Thank you for reading and please remember to like, share, and check out my other posts!

[1] Rilles are long narrow depressions on the lunar surface that look like channels.

[2] International space treaties declare no state shall lay claim to territory off Earth, but say nothing against corporations and private citizens.

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Bibliography

• Chaikin, Andrew. “The Other Moon Landings.” Air & Space Magazine, Mar. 2004, wayback.archive-it.org/all/20140511103222/www.airspacemag.com/space/the-other-moon-landings-6457729/.

• Howell, Elizabeth. “Lunokhod 1: 1st Successful Lunar Rover.” Space.com, Space, 20 Dec. 2016, www.space.com/35090-lunokhod-1.html.

• “In Depth — Lunokhod 1.” NASA, NASA, 15 Mar. 2018, solarsystem.nasa.gov/missions/lunokhod-01/in-depth/.

• “In Depth — Lunokhod 2.” NASA, NASA, 15 Mar. 2018, solarsystem.nasa.gov/missions/lunokhod-02/in-depth/.