FEATURE: Lunokhod 2 Луноход-2 (“moon walker”)
ON JANUARY 15th 1973 the Soviet Union landed their second lunar rover on the moon. Lunokhod 2 (vehicle 8ЕЛ№204) was the second and more advanced of the two unmanned lunar rovers landed on the Moon by the Soviet Union as part of the Lunokhod program. The launcher put the spacecraft into Earth parking orbit on January 8, 1973, followed by a translunar injection. On January 12, 1973, Luna 21 was braked into a 90 by 100 km (56 by 62 miles) lunar orbit.
The Luna 21 spacecraft landed on the Moon to deploy the second Soviet lunar rover, Lunokhod 2. The primary objectives of the mission were to collect images of the lunar surface, examine ambient light levels to determine the feasibility of astronomical observations from the Moon, perform laser ranging experiments from Earth, observe solar X-rays, measure local magnetic fields, and study mechanical properties of the lunar surface material.
The landing occurred on January 15, 1973 at 23:35 UT in Le Monnier crater (25.85 degrees N, 30.45 degrees E).
In Return to the Moon
Technical documents at
Lunokhod 2 and the Soviet Moon Programme
On January 16, 1973, Soviet unmanned lunar rover Lunokhod 2 took its first TV images of the surrounding area, then rolled down a ramp to the surface of the Moon, and took first pictures of the landing site. Lunokhod 2 was the second of two unmanned lunar rovers landed on the Moon by the Soviet Union as part of the Lunokhod programme. The Lunokhods were primarily designed to support the Soviet manned moon missions during Moon race. Instead, they were used as remote-controlled robots for exploration of the lunar surface and return its pictures after the successful Apollo manned lunar landings and cancellation of Soviet manned moon program.
Lunokhod’s original primary mission was the back-up for L3 manned moon expeditions and for later Zvezda lunar base. It was intended to send an LK-R lander in unmanned L3 lunar expedition complex and two Lunokhod automated rovers to the Moon for preliminar study of surface. Further, LK-R was supposed to be used as a reserve escape craft in case of disability to start from Moon of LK and Lunokhods used by cosmonaut for transfer to LK-R in necessity and for regular research.
Lunokhod 1 was the first of two unmanned lunar rovers successfully landed on the Moon by the Soviet Union as part of its Lunokhod program. It was launched on November 10, 1970 and carried by Luna 17. After two course correction manoeuvres it entered lunar orbit five days later and soft-landed on the Moon in the Sea of Rains on November 17. Lunokhod 1 moved onto the Moon’s surface and ran during the lunar day, stopping occasionally to recharge its batteries via the solar panels. At night the rover hibernated until the next sunrise, heated by the radioisotope heater unit.
Lunokhod 2 was the second and more advanced of two unmanned lunar rovers landed on the Moon by the Soviet Union as part of the Lunokhod program. On January 12, 1973, Luna 21 was braked into a lunar orbit and landed on the Moon three days later. The primary objectives of the mission were to collect images of the lunar surface, examine ambient light levels to determine the feasibility of astronomical observations from the Moon, perform laser ranging experiments from Earth, observe solar X-rays, measure local magnetic fields, and study mechanical properties of the lunar surface material. After landing, the Lunokhod 2 took TV images of the surrounding area, then rolled down a ramp to the surface and took pictures of the Luna 21 lander and landing site.
The rover was equipped with three slow-scan television cameras, one mounted high on the rover for navigation, which could return high resolution images at different rates. The images were used by a five-man team of controllers on Earth who sent driving commands to the rover in real time. The main power source was a solar panel and a polonium-210 radioactive heat source was used to keep the rover warm during the long lunar nights. Further, Lunokhod 2 was equipped with several scientific instruments including a Soil Mechanics tester, Solar X-ray experiment, an Astrophotometer to measure visible and Ultraviolet light levels, a Magnetometer, a Radiometer, a Photodetector for laser detection experiments, and a French-supplied laser Corner Reflector.
In summer 1973 it was announced that the program was completed and it is believed that Lunokhod 2 traveled around 39km on Moon’s surface which is the second longest rover traveled distance recorded. Lunokhod 2 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.
The Lavochkin Association sold Lunokhod 2 and the Luna 21 lander $68,500 in December 1993 at a Sotheby’s auction in New York. The buyer was computer gaming entrepreneur and astronaut’s son Richard Garriott, who stated in a 2001 interview with Computer Games Magazine’s Cindy Yans that: “I purchased Lunakod 21 [sic] from the Russians. I am now the world’s only private owner of an object on a foreign celestial body. Though there are international treaties that say, no government shall lay claim to geography off planet earth, I am not a government. Summarily, I claim the moon in the name of Lord British!”
In SciHi Blog
The Day a Soviet Moon Rover Refused to Stop
A formerly secret report details the triumphs and setbacks of an early lunar mission.
Forty-five years after the Soviet Lunokhod-2 robot explored the lifeless surface of the moon, a declassified document sheds new light on the legendary project.
The 125-page technical report published this week was written in the months immediately following the 1973 mission by members of the Lunokhod communications team, who were responsible for controlling cameras and radios aboard the eight-wheeled rover and monitoring its health.
The second, and what turned out to be the last, Soviet rover to operate on the lunar surface blasted off on January 8, 1973, and landed on the moon eight days later. Officially dubbed Luna-21, it came down inside a 34-mile-wide crater called Le Monnier, a little over 100 miles north of where NASA’s Apollo 17 astronauts had explored just a month earlier.
After rolling off its landing platform, Lunokhod-2 traveled for 23 miles, beaming 69,000 TV images back to Earth and producing 86 panoramas of the surrounding landscape. It also probed the strength of the lunar surface in numerous locations and received laser beams fired from Earth.
To the people who worked on Lunokhod-2, the lander was known as Article E8 No. 204. The newly released document details the months of painstaking preparations that led up to launch, including a series of failures in the rover’s programming timer during tests at the launch site in September and October 1972. Engineers had to remove the entire unit from the rover and take apart its components. The problem was eventually traced to a massive short-circuit in an avionics box, due to mechanical damage that resulted from its being forced into position in its holding compartment. After replacing the unit, engineers repeated the entire test routine for the communications system, which seriously shortened its lifespan during the actual mission. This finally explains why Lunokhod-2 survived only around four months on the moon, as compared to 10 months for its predecessor, Lunokhod-1.
The rover’s Earth-based drivers compensated for this shortened lifespan with much faster driving, which produced its own drama. According to the report, the first lunar day of Lunokhod-2’s journey went smoothly, with only a few minor glitches. But when driving resumed on February 11 after a period of hibernation, the operators experienced their first serious problem. Lunokhod-2 refused to immediately stop when the team spotted a crater ahead and issued a stop command. “The motion of the rover was (still) observed based on the shifting of the images on the VKU screen of the MKTV (TV) system,” the report says.
Only after repeating the stop command three times did the stubborn vehicle finally come to a halt. The problem was traced to a signal scrambler in the radio system, which led mission controllers to switch to a secondary scrambler.
Harsh temperatures on the moon also forced them to reduce the number of panoramic images taken by the rover. Still, Lunokhod-2 successfully completed its second lunar day on February 22, and hibernated until March 9.
Problems with the secondary radio scrambler got worse during the third lunar day, however, and the engineers switched to another radio channel operating on a different frequency.
By May 10, during the 503rd communications session, engineers discovered that the temperature inside Lunokhod-2 had soared as high as 47 degrees C (116 degrees F). Flight controllers immediately turned off onboard systems and ended the communications session, but all subsequent attempts to talk to Lunokhod-2 proved fruitless, according to the report. The document gives the exact time of Lunokhod’s death as May 10, 1973, at 15:25 (Moscow time).
Previous accounts of the mission appeared to blame the rover’s demise on a May 9 incident in which its solar panel scraped a particularly steep crater wall and became covered with dust. However, the newly declassified report stresses that by the time Lunokhod-2 stopped talking to mission control, its transmitters were already well past their warranty date—which appears to attribute the rover’s end to the communications system failure.
At the time Lunokhod-2 died, the team was still hoping to apply its engineering lessons to Lunokhod-3 and -4 (using vehicles No. 205 and 206). One drawback they wanted to fix was the inability to rotate the cameras independently of the rover’s body. The authors of the report also recommended installing the cameras at least six feet above the surface to provide a better view for the drivers.
That somebody listened to their recommendations is evident from the flightworthy model of Lunokhod-3 now displayed in a museum at the NPO Lavochkin company near Moscow. Unfortunately, the Soviet lunar program had lost momentum by that time, and Lunokhod-3 never had a chance to fly.
In Air Space Mag
Luna 21/Lunokhod 2
The Luna 21 spacecraft landed on the Moon and deployed the second Soviet lunar rover (Lunokhod 2). The primary objectives of the mission were to collect images of the lunar surface, examine ambient light levels to determine the feasibility of astronomical observations from the Moon, perform laser ranging experiments from Earth, observe solar X-rays, measure local magnetic fields, and study mechanical properties of the lunar surface material.
Lunokhod 2 Rover and Subsystems
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/hr and ~2 km/hr. 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.
The SL-12/D-1-e launcher put the spacecraft into Earth parking orbit followed by translunar injection. On 12 January 1973, Luna 21 was braked into a 90 x 100 km orbit about the Moon. On 13 and 14 January, the perilune was lowered to 16 km altitude. On 15 January after 40 orbits, the braking rocket was fired at 16 km altitude, and the craft went into free fall. At an altitude of 750 meters the main thrusters began firing, slowing the fall until a height of 22 meters was reached. At this point the main thrusters shut down and the secondary thrusters ignited, slowing the fall until the lander was 1.5 meters above the surface, where the engine was cut off. Landing occurred at 23:35 UT in LeMonnier crater at 25.9994 degrees N, 30.4077 degrees E. The lander carried a bas relief of Lenin and the Soviet coat-of-arms.
After landing, the Lunokhod 2 took TV images of the surrounding area, then rolled down a ramp to the surface at 01:14 UT on 16 January and took pictures of the Luna 21 lander and landing site. It stopped and charged batteries until 18 January, took more images of the lander and landing site, and then set out over the Moon. The rover would run during the lunar day, stopping occasionally to recharge its batteries via the solar panels. At night the rover would hibernate until the next sunrise, heated by the radioactive source. 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.
SOVIET REPORT DETAILING LUNAR ROVER LUNOKHOD-2 RELEASED FOR FIRST TIME
Russian space agency Roskosmos has released an unprecedented scientific report into the lunar rover Lunokhod-2 for the first time, revealing previously unknown details about the rover and how it was controlled back on Earth.
The report, written entirely in Russian, was originally penned in 1973 following the Lunokhod-2 mission, which was embarked upon in January of the same year. It had remained accessible to only a handful of experts at the space agency prior to its release today, to mark the 45th anniversary of the mission.
Bearing the names of some 55 engineers and scientists, the report details the systems that were used to both remotely control the lunar rover from a base on Earth, and capture images and data about the Moon’s surface and Lunokhod-2’s place on it. This information, and in particularly the carefully documented issues and solutions that the report carries, went on to be used in many later unmanned missions to other parts of the solar system.
As a result, it provides a unique insight into this era of space exploration and the technical challenges that scientists faced, such as the low-frame television system that One detail that main be of particular interest to space enthusiasts and experts is the operation of a unique system called Seismas, which was tested for the first time in the world during the mission.
Designed to determine the precise location of the rover at any given time, the system involved transmitting information over lasers from ground-based telescopes, which was received by a photodetector onboard the lunar rover. When the laser was detected, this triggered the emission of a radio signal back to the Earth, which provided the rover’s coordinates.
Other details, while technical, also give some insight into the culture of the mission, such as the careful work to eliminate issues in the long-range radio communication system. One issue, for example, was worked on with such thoroughness that it resulted in one of the devices using more resources than it was allocated, a problem that was outlined in the report.
The document also provides insight into on-Earth technological capabilities of the time. While it is mostly typed, certain mathematical symbols have had to be written in by hand, and the report also features a number of diagrams and graphs that have been painstakingly hand-drawn.
Lunokhod-2 was the second of two unmanned lunar rovers to be landed on the Moon by the Soviet Union within the Lunokhod programme, having been delivered via a soft landing by the unmanned Luna 21 spacecraft in January 1973.
In operation between January and June of that year, the robot covered a distance of 39km, meaning it still holds the lunar distance record to this day.
One of only four rovers to be deployed on the lunar surface, Lunokhod-2 was the last rover to visit the Moon until December 2013, when Chinese lunar roverYutu made its maiden visit.