Off-road vehicles for the ages

So far, humanity has shot six cars at the moon. One is still driving. The story of the insane race to mobilize the moon began more than half a century ago.

From Harold Kaiser

Only 80 meters? That sounds like a hop, a no-brainer. In any case, after a distance that can be covered by car in a minute. At least if you apply an earthly standard. But not on the moon with its special conditions. The Chinese moon car Jadehase 2 is facing this seemingly ridiculous trip. It is the only one of seven international vehicles that is still cruising around on Earth's satellite. The other six from the USA, Russia and one more from China (Jadehase 1) are now retired.

At the beginning of December 2021, the still active scout from the Middle Kingdom was commissioned to roll to a strange structure 80 meters away in order to be able to examine it from close proximity and send images to earth. So far, scientists have had to be content with blurry photos that were shot from a distance. It is unclear whether the dreary gray wasteland is a boulder, a strangely shaped heap of moondust or possibly an illusion.

The sun does not always provide electricity

The supposed hopping jump can by no means be mastered in a few minutes. Not even in two or three days. Because Jade Bunny 2 is not only a particularly lame duck with a speed of one meter per lunar day, he also has to struggle with special requirements. A lunar day extends over 14 earthly days, which is due to the position of the moon to the sun. Only then does the central star of our galaxy shine sufficiently so that Jadehase 2 can generate enough current for the electric motors on the six wheels with the help of its solar paddles. However, on the moonlit night, which also lasts 14 earth days, the scout has to pause because the weak sunlight does not provide enough energy. So the mission will drag on in time. In purely mathematical terms, the rover would need 5,7 months to reach its destination. He would achieve this around Easter 2022, provided that no obstacles have to be avoided over a large area.

The Russian Lunochod 1: 756 kilograms, 8 engines ensure a top speed of 2,5 km / h

The Asian scout landed on the far side of the moon in December 2018 in the huge Von Kármán crater of the South Pole Aitken Basin. Experts estimate that he has driven about 500 meters since then. In order to be able to control it remotely there, a satellite had to be shot up and brought into position. Otherwise the lightning-fast radio commands, which run over the gang, so to speak, would be sent to nowhere. He inherited the funny name, named after the animal companion of the moon goddess "Chang'e" from Chinese mythology, from his predecessor Jadehase 1. In the course of an online vote, the majority of a good 650.000 participants thought this term was appropriate.

The "Jade Bunny" fell silent a long time ago

Jadehase 1 only partially fulfilled the hopes placed in him. Because Robbie, who is also equipped with solar cells and an electric drive, weighs 140 kilos and is 1,5 meters short, got stuck in the partially ankle-deep moondust after just 114 meters. For this, his scientific devices worked far longer than the planned three months, namely more than two and a half years. On July 31, 2016, it finally fell silent because the technology had given up at temperatures of more than 100 degrees below zero.

The Chinese "Jade Bunny" is now retired

His end was communicated to the world in a special way - in first person form. The public relations workers at the space agency composed this farewell sentence for him, as if he could have spoken: “There are still many questions I would answer, but I am the rabbit who has seen the most stars! The moon says it has prepared a long, long dream for me. ”Before China revived mobilization on the moon with the first version of the jade bunny on December 14, 2013, there was 40 years of stagnation. No automobile whirled up moondust for so long. The last earthly scout to date was the Russian Lunochod 2, which finally froze forever in May 1973 due to the brutal cold of space.

The mad race began in 1970

In 1970 the mad race between the great powers of the Soviet Union and the USA for mobilization began high above our heads. The triggering event for these long-lasting muscle games was a painful blow into the self-image of the United States, which at the same time spurred the Americans on to new exploits. On the night of November 16-17, 1970, the leadership team of the US space agency NASA will have found no sleep, or only with difficulty, because they must have been kept awake by the news of the Soviet Union's latest and successful space mission.

At that time the Russians managed to catch up with the USA again: They shot the first automobile at the dusty earth satellite - Lunochod 1. That was more than 50 years ago. One day after landing, the New York Times reported in sober news language on page one: "Eight-wheeled Soviet vehicle maneuvering on the moon." July 21 became the first person to step on the moon. Reason enough actually for the USA not to have to feel caught up in this epoch-making achievement. And yet the emotional state in the phase was probably like that at NASA. There they knew that Armstrong's breathtaking step would challenge the rival world empire USSR to an undertaking of at least equal value. For example, if she should succeed in launching a rocket with an extraordinary cargo on top into space.

Luna 17 landed gently in the dust

That night it happened to the car that is about the size of the small car Smart. The Americans did not want to leave this hit unanswered in the bitter race between the two nations for supremacy in space. Because the exchange of blows was no longer just about technical-scientific leadership or satisfying the vanity of top political personnel. These billion-dollar projects primarily served the claim to world power and the demonstration of the superiority of the other political system.

In the early morning of November 17 at 6:47 am Moscow time, the Russian space command reported: The space capsule Luna 17 landed relatively gently in the dust of the “Mare Imbrium” region on the Earth-facing side of the moon at a sink rate of two meters per second. A picture book landing. When this success message came in, the Marshall Space Flight Center in Huntsville / Alabama had just passed midnight due to the time difference. Exactly 0:47 a.m.

The driver of "Lunachod 1" was sitting on the ground

About 75 minutes after touchdown, the Americans also had to acknowledge that the car was actually working. At around 2:02 am in Huntsville, the driver of Lunochod 1 reported to the overheard radio traffic with the words: “I see the surface of the moon. It's flat and beautiful. ”Laypeople would certainly have been taken aback by this sentence, after all, a driver always sees what is happening in front of him. Not so the NASA experts, who knew exactly what was meant: The driver of the moon mobile was not in the car, but a good 385.000 kilometers away in the control center in Evpatoria on the Crimean peninsula on the Black Sea. A masterpiece.

From there he directed the vehicle together with four other men - the commander, engineer, navigator and radio operator - from the lowered ramp to the surface of the moon. The images for this were provided by two black and white television cameras on the front of the car, which flickered on a monitor in the Crimea. Lunochod reacted to the radio steering commands that the driver gave on earth with the help of a control lever. What sounds simple, was anything but that. Because despite the speed of light (approx. 300.000 kilometers per second), image and radio signals always arrived with a delay of about three seconds for the 770.000 kilometers earth-moon-earth route due to the necessary reconfirmation. In addition, the driver had a reaction time of around one second. This meant that the bathtub-like vehicle on the earth's satellite was always a little further than the images currently arriving on earth showed.

Eight electric motors on eight wheels

In addition, a small design flaw was recognized soon after landing: cameras that were mounted too low made Lunochod to a certain extent short-sighted because their angle of view was too focused on the ground. If, for example, a large stone came into view that had to be avoided quickly, the time delay and the restricted field of view necessitated rapid steering. The situation was similar when accelerating or braking, both of which could be controlled by simply accelerating or releasing the accelerator with the help of the electric motors on each of the eight wheels. Thankfully, the robot vehicle was not fast. The top speed was only 2-3 km / h.

While this adventure caused astonishment all over the world, in addition to the slight time delay, the command team repeatedly struggled with weak radio signals, with often faltering and sometimes blurred TV images and, at best, with a moderate orientation. After all, modern electronic scouts like Google Maps weren't even part of dreams. Instead, the navigator had to deal with paper moon maps. Judging by this, it is a fantastic achievement to have freed the sometimes stuck “moon walker”, as Lunochod translates, from craters or otherwise difficult terrain. Last but not least, this was achieved thanks to a kind of crampon on the treads of the eight wheels and a courageous jolting back and forth.

The lifetime was almost eleven months

His lifetime was calculated to be a quarter of a year. But the construction turned out to be far more solid and worked much longer. Almost eleven months. In the meantime, she gathered a huge amount of new information about the chemical and physical properties of the moon, about its geology and geography, around 20.000 photos were transmitted, the ground was analyzed a good 500 times with special devices, and cosmic rays were constantly measured. The electricity for all of this work was provided by solar cells in the movable cover of the funny-looking moving tub. It opened automatically in daylight and closed in the dark.

This not only because electricity could not be generated without sunlight, but also because the sensitive measuring devices in the tub only had to be protected from the cold with the lid closed and at the same time kept warm by an atomic heater. At the beginning of October 1971, Lunochod 1 finally stopped making a sound - like its brother model later, it was frozen. Even the special heating apparently couldn't do anything against the brutal night cold. It was powered by a small amount of radioactive polonium, which generates heat as a side effect during its decay process. But that was no longer enough. The first man-made lunar vehicle left an eternally recognizable wheel track of 10,5 kilometers in the dust of the surface. It ends in the hilly landscape of the “Cap Heraclides” region.

The first space probe "Sputnik" was launched in 1957

Beyond the terrestrial transport of cars into space, the actual race for dominance in space had been going on for more than a quarter of a century at the time. With constant changes in leadership and different equipment. The national competition was started by the Soviets on October 4, 1957. At that time, they shot Sputnik 1 from the cosmodrome in Baikonur / Kazakhstan into orbit. The first space probe known to man. From a maximum orbit altitude of 939 kilometers, it sent short-wave beeps to earth that could be received anywhere.

These were sounds that gave Americans severe earache. Because with the spherical Sputnik (83,6 kilograms, 58 centimeters in diameter) it was proven that it is possible to transport objects into space that could pose a risk. Sputnik burned up 92 days after takeoff when it penetrated deeper layers of the earth's atmosphere. But the conclusion from the Sputnik mission that the Soviet Union might be able to reach the US with armed ICBMs in the near future sparked such an immense sense of threat in the US Congress that the administration of President Dwight D. Eisenhower dissociated itself was forced to take countermeasures.

The Sputnik shock led to the founding of NASA

This fear, also known as Sputnik shock, led to the founding of NASA in July 1958 and thus to a large number of space missions on both sides over the decades. The US programs were called, among other things, "Mariner", "Mercury", "Gemini" or "Apollo". Those of the Soviets called themselves "Lunik", "Luna", "Wostok", "Voschod" or "Salyut". It happened in quick succession. Sometimes the Americans were ahead of the game, then the Russians again. Like on April 12, 1961, when Lieutenant Yuri Gagarin was the first person to be chased into orbit at the head of a powerful Vostok launcher and orbited the earth once in his capsule. 108 minutes later, it landed on parachutes near the cities of Saratov and Engels in the Volga region. Gagarin was a hero, promoted to major, and the world had another space sensation.

The US President John F. Kennedy, who took office in January of the same year, assessed the Gagarin campaign as a national disgrace. So America had to show again that it could do even better. Cost what it may. Kennedy formulated the claim to world power on May 25, 1961 before the US Congress: “I believe that this nation should undertake to achieve the goal of having a person land on the moon before the end of this decade, and then him safely back to earth. ”In 1969, eight years after this direction was issued, US astronaut Neil Armstrong set foot on the moon. This demonstration of strength came at just the right time, because both countries were in the middle of the cold war and were constantly looking for opportunities to raise their profile and threaten the other great powers.

The folded lunar car came to the moon with Apollo 15

Two years later, on July 26, 1971, Apollo 15 was finally ready to be launched on the launch pad of the Kennedy Space Center in Florida. On board the giant Saturn rocket were the three astronauts David Scott, James Irwin and Alfred Worden (as commander of the space capsule "Endeavor") and the folded first space car in the USA, which looked like a cheap desert buggy, but more than 40 million dollars Devoured development costs.

With the “Lunar Roving Vehicle” (LRV) it was not only possible to extend the astronauts' radius of action from what was once a few hundred meters on foot to several kilometers on the move. What was much more decisive was that the car did not have to be laboriously remote-controlled, as was the case with the Soviets, but that two astronauts could take a seat in it and drive it themselves. In addition, the open car had four-wheel drive to be on the safe side, which was supposed to prevent it from getting stuck in the sometimes deep moondust. You had experience with Neil Armstrong's legendary first steps. Co-space pilot David Scott later reported that the surface consisted of a 15 centimeter thick layer of dust that felt like powder snow.

Everything went like clockwork, the take-off, landing near the Hadley mountain range on July 30th, pulling out and unfolding the wheels of the off-road vehicle as well as the return start to earth on August 2nd, 1971. Scott and Irwin lay during of their two-day stay with the space buggy 27,8 kilometers with a total travel time of three hours and two minutes. Maximum speed: 14 km / h.

The NASA car was trimmed to be lightweight

In contrast to its heavy Russian counterpart (756 kilos), everything on the NASA car was trimmed to reduce weight. From the aluminum frame to the two aluminum seats to the four lightweight wheels made of a flexible wire mesh with titanium inserts in the tread. The car weighed only 210 kilos and was powered by an electric motor per wheel. Performance together: one horsepower. The fact that the car was also given all-wheel steering paid off right at the beginning of the mission. Shortly after opening it, Scott radioed that the front steering was not working, but that was not a problem, because he could steer with the rear wheels.

The two astronauts explored craters, mountains and valleys on their three tours. They controlled the car using a lever in the middle of the cockpit, which already looked and worked like a joystick for computer games today. David Scott judged the driving characteristics on the funk as follows: “This is a rock 'n' roll ride. I get seasick. ”In fact, what was shown on US television on July 30, 1971, was a wild ride. To the accompaniment of country music, the Lunar Rover sometimes lifted up with all four wheels.

Fortunately, they were buckled up. But before starting the first trip, Scott and Irwin had difficulties with it. The seat belts, which had been fitted to prevent weightlessness and the risk of the astronauts being unbuckled from the car on uneven slopes, were very difficult to fasten. Strangely enough, the straps running across the middle of the thighs no longer seemed long enough in contrast to training on the ground. The reason for this can be found in NASA's final mission report from December 1971: Because of the lower gravity on the moon, the pressure suits were much less compressed while sitting than on earth. So Scott and Irwin were a bit puffed up and sat a few inches higher than planned due to this circumstance. Because of this, their belts were harder to fasten and were also much tighter.

The first American sled for use in a vacuum, largely co-developed by the German-American rocket engineer Georg von Tiesenhausen and built by Boeing and General Motors, was followed by two more cars in April and December 1972 (Apollo 16 and 17). All equipped with TV cameras, transmitter and receiver units, various scientific measuring devices and a navigation computer each so that the crews could safely find their way back to their combined landing and take-off modules in the gray monotony of the moon. Because with them they should jet back home after the end of their moon excursions.

Deadly cold ended the life of Lunochod 2

In January 1973, the Lunochod 2, the last moon car for decades, joined the now three US off-road vehicles. At 840 kilograms it was the heavyweight of all previous moon vehicles and at 39 kilometers it made the longest journey at the time. While the previous model put an end to the cold, Lunochod 2 first died of heat before it froze too. The 'International Atlas of Lunar Exploration' describes the exact course of events as follows: “Towards the end of the lunar day, the rover drove with the sun behind it and poor visibility. He was accidentally steered into a small crater. When trying to maneuver it out again, the open flap with the solar cells, which protruded backwards over the fuselage, hit the crater wall, whereupon it and its solar cells were partially covered with lunar material. The ground team noted a drop in energy performance but did not consider it a serious problem. But when the flap was closed a little later to keep the rover somewhat warm during the lunar night, this lunar material spilled onto the cooler, the purpose of which was to prevent the rover from overheating during the lunar day ... On May 8, 1973, Lunochod was 2 awakened again and the journey ... continued. But eventually he overheated ... "Then he fell prey to the deadly cold.

Except for the remaining Jadehase activists, the earthly car fleet consists of six long-term parkers. The multimillion-dollar used electric vehicles from Russia, the USA and China stand lonely and abandoned widely scattered in the dust. Each with a ridiculously few kilometers on the clock and no prospect of reactivation. Because there has long been no chemical process in your battery cells that could generate energy and get it going again. It's a parking lot for the ages.

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