Lunokhod 2 (Russian: Луноход-2 ("Moonwalker 2"), also known as Аппарат 8ЕЛ № 204 ("Device 8EL No. 204")) was the second of two unmanned lunar rovers that landed on the Moon by the Soviet Union as part of the Lunokhod programme.
![]() Model of Lunokhod 2 rover | |
Mission type | Lunar rover |
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COSPAR ID | 1973-001A |
Spacecraft properties | |
Dry mass | 840 kilograms (1,850 lb) (rover only) |
Start of mission | |
Launch date | January 11, 1973, 06:55:38 (1973-01-11UTC06:55:38Z) UTC |
Rocket | Proton-K/D |
Launch site | Baikonur 81/23 |
End of mission | |
Last contact | May 11, 1973 (1973-05-12) |
Lunar rover | |
Spacecraft component | Rover |
Landing date | January 15, 1973 |
The Luna 21 spacecraft landed on the Moon and deployed the second Soviet lunar rover, Lunokhod 2, in January 1973.[1][2][3] 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 the soil mechanics of the lunar surface material.
The rover stood 135 centimetres (4 feet 5 inches) high and had a mass of 840 kg (1,850 lb). It was about 170 centimetres (5 feet 7 inches) long and 160 centimetres (5 feet 3 inches) wide and had eight wheels each with an independent suspension, electric motor and brake. The rover had two speeds, about 1 and 2 km/h (0.62 and 1.24 mph). Lunokhod 2 was equipped with three television cameras, one mounted high on the rover for navigation, which could return high resolution images at different frame 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 radioisotope heater unit was used to keep the rover warm during the long lunar nights. There were four panoramic cameras mounted on the rover. Scientific instruments included a soil mechanics tester, solar X-ray experiment, an astrophotometer to measure visible and ultraviolet light levels, a magnetometer deployed in front of the rover on the end of a 2.5 m (8 ft 2 in) boom, a radiometer, a photodetector (Rubin-1) for laser detection experiments, and a French-supplied laser corner reflector. The lander carried a bas relief of Vladimir Lenin and the State Emblem of the Soviet Union. The lander and rover together massed 1814 kg.
The Proton-K/D launcher put the spacecraft into Earth parking orbit followed by translunar injection. On January 12, 1973 Luna 21 was braked into a 90 by 100 km (56 by 62 mi) lunar orbit. On January 13 and 14, the perilune was lowered to 16 km (9.9 mi) altitude.
On January 15, 1973, after 40 orbits, the descent of the craft was commenced as the braking rocket was fired at 16 km (9.9 mi) altitude, and the craft began to de-orbit. At an altitude of 750 m (2,460 ft) the main thrusters began firing, slowing the fall until a height of 22 m (72 ft) was reached. At this point the main thrusters shut down and the secondary thrusters ignited, slowing the fall until the lander was 1.5 m (4.9 ft) above the surface, where the engine was switched off. Landing occurred at 23:35 UT in Le Monnier crater at 25.85 degrees N, 30.45 degrees E.
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 January 16 and took pictures of the Luna 21 lander and landing site, driving for 30 metres. After a period of charging up its batteries, it took more pictures of the site and the lander, and then set off to explore the moon.
The rover would run during the lunar day, stopping occasionally to recharge its batteries with the solar panels. At night the rover hibernated until the next sunrise, heated by the radioactive source.
On June 4, 1973 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.
More recently, Alexander Basilevsky related an account in which on May 9, the rover's open lid touched a crater wall and became covered with dust. When the lid was closed, this dust (a very good insulator) was dumped on to the radiators. The following day, May 10, controllers saw the internal temperature of Lunokhod 2 climb as it was unable to cool itself, eventually rendering the rover inoperable.[4] On May 11, signal from the rover was lost.
Lunokhod 2 operated for about four months, and the original estimate was that it covered 37 km (23 mi) of terrain, including hilly upland areas and rilles, and sent back 86 panoramic images and over 80,000 TV pictures.[4][5][6] Many mechanical tests of the surface, laser ranging measurements, and other experiments were completed during this time. Lunokhod 2 was thought to have covered 37 km (23 mi) based on wheel rotations but Russian scientists at the Moscow State University of Geodesy and Cartography (MIIGAiK) revised that to an estimated distance of about 42.1–42.2 km (26.2–26.2 mi) based on Lunar Reconnaissance Orbiter (LRO) images of the lunar surface.[7][8] Subsequent discussions with their American counterparts ended with an agreed-upon final distance of 39 km (24 mi);[9][10] an international team has confirmed that the methods used to calculate the two rovers' odometry is consistent and comparable from the Moon to Mars.[11]
Lunokhod 2 held the record for off-Earth roving distance until July 27, 2014, when NASA's Mars Opportunity rover exceeded it after having traveled over 40 km (25 mi).[12][13]
Lunokhod 2 continues to be detected by lunar laser ranging experiments and its position is known to sub-meter accuracy.[15] On March 17, 2010 Phil Stooke at the University of Western Ontario announced that he had located Lunokhod 2 in NASA Lunar Reconnaissance Orbiter (LRO) images,[16][17][18] but later images showed the initial identification was incorrect (the identified point was a mark in the rover tracks near the end of the route, made as Lunokhod 2 turned around), and the LRO LROC team identified the correct location of the rover in March 2012.[5][19] Excellent Lunokhod 2 images from LROC were published by Mark Robinson on SESE site of ASU.[20]
Ownership of Lunokhod 2 and the Luna 21 lander was sold by the Lavochkin Association for $68,500 in December 1993 at a Sotheby's auction in New York.[18][21] (The catalog[22] incorrectly lists lot 68A as Luna 17/Lunokhod 1).
The buyer was computer gaming entrepreneur and space tourist Richard Garriott (son of the astronaut Owen K. Garriott), who stated in a 2001 interview with Computer Games Magazine's Cindy Yans that:
Garriott later confirmed that he is the owner of Lunokhod 2.[18][24][25]
Richard A. Garriott has finally seen the item he bought 17 years ago for $68,500.
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← 1972 · Orbital launches in 1973 · 1974 → | |
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Luna 21 (Lunokhod 2) | Kosmos 543 | Kosmos 544 | Kosmos 545 | Kosmos 546 | Kosmos 547 | Molniya-1 No.31 | Kosmos 548 | Prognoz 3 | Kosmos 549 | Kosmos 550 | Kosmos 551 | OPS 6063 | OPS 8410 | Meteor-M No.29 | Kosmos 552 · Nauka-16KS No.2L | Salyut 2 | Molniya-2-5 | Pioneer 11 | Kosmos 553 | Kosmos 554 | Interkosmos 9 | Anik A2 | Unnamed | Kosmos 555 · Nauka-14KS No.2 | Kosmos 556 | Kosmos 557 | Skylab | OPS 2093 | Kosmos 558 | Kosmos 559 | Unnamed | Kosmos 560 | Unnamed | Skylab 2 | Kosmos 561 · Nauka-9KS No.1 | Meteor-M No.27 | Kosmos 562 | Kosmos 563 | Kosmos 564 · Kosmos 565 · Kosmos 566 · Kosmos 567 · Kosmos 568 · Kosmos 569 · Kosmos 570 · Kosmos 571 | Kosmos 572 | Explorer 49 | OPS 6157 | Kosmos 573 | Kosmos 574 | Kosmos 575 | OPS 4018 | Kosmos 576 | Unnamed | Molniya-2-6 | OPS 8261 | ITOS-E | Mars 4 | Kosmos 577 | Mars 5 | Skylab 3 | Kosmos 578 | Mars 6 | Mars 7 | OPS 8364 | Kosmos 579 | OPS 7724 | Kosmos 580 | Intelsat IV F-7 | Kosmos 581 | Kosmos 582 | Molniya-1-24 | Kosmos 583 | Kosmos 584 | Kosmos 585 | Kosmos 586 | Unnamed | Kosmos 587 | Soyuz 12 | OPS 6275 | Kosmos 588 · Kosmos 589 · Kosmos 590 · Kosmos 591 · Kosmos 592 · Kosmos 593 · Kosmos 594 · Kosmos 595 | Kosmos 596 | Kosmos 597 | Kosmos 598 | Kosmos 599 | Kosmos 600 | Kosmos 601 | Molniya-2-7 | Kosmos 602 | Explorer 50 | Kosmos 603 | Kosmos 604 | Transit-O 20 | Interkosmos 10 | Kosmos 605 | Kosmos 606 | Mariner 10 | NOAA-3 | Kosmos 607 | OPS 6630 · OPS 6630/2 · OPS 7705 | Molniya-1 No.32 | Skylab 4 | Kosmos 608 | Kosmos 609 | Kosmos 610 | Kosmos 611 | Kosmos 612 | Kosmos 613 | Molniya-1-26 | Kosmos 614 | Kosmos 615 | OPS 9433 · OPS 9434 | Explorer 51 | Kosmos 616 | Soyuz 13 | Kosmos 617 · Kosmos 618 · Kosmos 619 · Kosmos 620 · Kosmos 621 · Kosmos 622 · Kosmos 623 · Kosmos 624 | Kosmos 625 | Molniya-2-8 | Oreol 2 | Kosmos 626 | Kosmos 627 | |
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets). |