Lunokhod, the first real rovers

 

 


 

Of course seen like this it looks very vintage, but Lunokhod was ahead of its time. NASA Credits

Originally intended to support the operations of cosmonauts on the lunar surface, Lunokhod rovers (or spacecraft) have gone down in history as the first true wheeled robots operating on a surface other than Earth. The program, eclipsed by Apollo, was nevertheless a resounding success.

They walked the roads, they went the distance ...

 

 

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From support to exploration


Which vehicle for the moon? The question animates the imagination even before the space race, since even Hergé equips his astronauts with a moon tank. When the Soviet Union began to work (too late) on its response to the Apollo program, the famous OKB-1 design office of Sergei Koroliov imagined a first version of the rover (or astromobile), which would have the task of prepare the site before the cosmonauts land, and help them install equipment on site. The engineer responsible for the program, Alexandre Kemourdjian, comes from the design of tanks, and this is reflected in the design of the machine. But he's also particularly drawn to remote-controlled systems, and that will prove to be very effective.

Unfortunately the first version developed for the N-1 is too big and too heavy: you have to change the launcher so that Lunokhod (literally 'lunar rover') can start. And thanks to the first robotic missions that touch the surface, the office is still changing it: it will be equipped with eight wheels, and no longer with tracks. The initial design was completed at the end of 1965.

 

 


 

Unfortunately, many Soviet projects collide with limited and compartmentalized resources. The manned program is struggling to put Soyuz into operation, the gigantic N1 rocket is very late, and the promising debut of the Proton launcher is being mobilized by other vehicles and probes (such as the Zond lunar missions). Built from 1967, the first copy of Lunokhod was ready at the start of 1969. After the American manned exploits of Apollo 8, successfully landing and operating a rover on the surface of the Moon would be a significant revenge: the USA have nothing equivalent in their boxes. Unfortunately for the USSR, the takeoff of Lunokhod-1 on February 19, 1969 goes very badly, and the robot will not reach orbit. Double disaster, the 25 kg of radioactive materials used to heat Lunokhod will never be found ...

A second Lunokhod could be ready quickly, but the authorities are changing their minds. To take the popular initiative back from the Americans, they decide to put the package on the projects of lunar sample returns. Renamed Lunokhod-1, the second robot will not finally leave for the Moon until November 10, 1970.

 

 

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A very nice pot ...


Lunokhod, without offending its designers, looks a bit like a closed tub placed on six wheels. It is relatively consistent with its dimensions, because it is a large rover: 1.35m high without counting the antennas, 2.2 meters long including the chassis, and 2.15m wide at the solar panel! The latter looks like the lid of an enormous pot, and closes again during lunar nights (reminder, there is daylight for 2 weeks, then night for a similar interval). At night, Lonokhod relies on its radioactive heat generator to keep its equipment alive. The motors are distributed over the hubs of its eight wheels, the suspensions of which absorb the shocks when moving this mastodon of almost 800 kg. They carry rudimentary but effective instruments for the time: cameras equipped to take panoramas, what to measure the distance and the resistance of the ground, an X-ray spectrometer, an X-ray detector, a small X-ray telescope , a French reflector per rover, and for Lunokhod 2, a photometer and a magnetometer.

 

 


 

Lunokhod is also an impressive landing platform, with a wingspan of 4m once the feet are deployed, intelligently designed and which will not disappoint! Reliability, engines and tanks, however, are paid for by a high mass: 4.9 tonnes for the platform alone. Once on lunar soil, it lowers two ramps which allow the rover to descend to roll on the regolith.

 

 

Lunokhod-1 lands successfully, Lunokhod-2 traces the road


7 days after takeoff from Baikonur, Luna-17 landed, and deployed the first Lunokhod on the lunar surface, in the rainy sea (northwest quarter visible). Its progression is not always easy, because it is not necessary to believe that the piloting was comparable to what is sent today to Curiosity or Yutu, which are very automated vehicles. For Lunokhod, it is neither more nor less than a very long distance remote control vehicle. There is therefore a real driver's station installed in Moscow which allows the rover to be piloted with a latency of about 5 seconds in the controls; quite correct for simple maneuvers.

By being careful, and despite some fears on the slopes of craters, the teams will succeed in making it last ten lunar days, or more than 300 Earth days, until September 14, 1971, with more than 10.5 km on the clock.

 


 

 

A feat reiterated with Lunokhod-2, an improved version of the first which took off on January 8, 1973 and landed in the Le Monnier crater on the 15th. This time, the rover (840 kg) and in particular its propulsion and its instruments, have been optimized. The mission is more efficient, but will survive for a shorter time, as the robot falls into a crater on May 9. Its panel covered in dust, it doesn't work as well anymore and the mission ends on June 2nd. Still, Lunokhod-2 produced and transmitted almost 80,000 pictures (unfortunately very few have been published), and traveled 37 kilometers! A record that will hold until 2015 with the Martian marathon of the little Opportunity.

 

 

A mixed heritage


Not only did the two rovers generate a deserved enthusiasm for their feat (even if it had little influence, in terms of history, on the race to the Moon which was already 'over'), but they brought back a scientific harvest. important. Soil resistance, chemical analysis of its components, detection of the tiny and fluctuating lunar magnetic field… Not to mention the use still available today of its laser reflectors. These devices, which can be compared to reflectors, reflect the light of a laser beam emitted from the Earth, which makes it possible to calculate the Earth-Moon distance with extreme precision. A measure also available with the sites of the Apollo missions, and which is implemented at regular intervals. Today we know the position of Lunokhod-2 within a meter!

 


 

 

Lunokhod is not a very popular program for today's audience. Soviet achievement arrived too late, it will have set a major milestone in space exploration. She was also briefly talked about in 1993 for the wrong reasons. In a ruined Russia, the Lavotchkine company sells everything it can think of. The English entrepreneur (and future private astronaut) Richard Garriott then buys the title deed of Luna-21 and Lunokhod-2 for 68,500 dollars…

 

 

 


 

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