 Model of Lunokhod 2 rover | |
| Mission type | Lunar rover |
|---|---|
| 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 | Baikonur81/23 |
| End of mission | |
| Last contact | May 11, 1973 (1973-05-12) |
| Lunar rover | |
| Spacecraft component | Rover |
| Landing date | January 15, 1973 |
Lunokhod 2 (Russian:Луноход-2 ("Moonwalker 2"), also known asАппарат 8ЕЛ № 204 ("Device 8EL No. 204")) was the second of twouncrewed lunarrovers that landed on theMoon by theSoviet Union as part of theLunokhod programme.
TheLuna 21 spacecraft landed on the Moon and deployed the second Sovietlunar rover,Lunokhod 2, in January 1973.[1][2][3] The lander and rover together massed 1814 kg.
The primary objectives of the mission were to collect images of the lunar surface, examineambient light levels to determine the feasibility of astronomical observations from the Moon, performlaser ranging experiments fromEarth, observe solarX-rays, measure localmagnetic fields, and study thesoil mechanics of thelunar 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 anindependent suspension,electric motor andbrake. The rover had two speeds, about 1 and 2 km/h (0.62 and 1.24 mph).
Lunokhod 2 was equipped with threetelevision cameras, one mounted high on the rover for navigation, which could return high resolution images at differentframe 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 asolar panel on the inside of a round hinged lid which covered the instrument bay, which would charge the batteries when opened. Apolonium-210radioisotope heater unit was used to keep the rover warm during the long lunar nights.
There were fourpanoramic cameras mounted on the rover. Scientific instruments included asoil mechanics tester, solar X-ray experiment, an astrophotometer to measure visible andultraviolet light levels, amagnetometer deployed in front of the rover on the end of a 2.5m (8 ft 2 in) boom, aradiometer, aphotodetector (Rubin-1) for laser detection experiments, and a French-supplied lasercorner reflector.
The lander carried abas relief ofVladimir Lenin and theState Emblem of the Soviet Union.
TheProton-K/D launcher put the spacecraft into Earthparking orbit followed bytranslunar 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, theperilune was lowered to 16 km (9.9 mi) altitude.
On January 15, 1973, after 40 orbits, the descent of the craft was commenced as thebraking 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 inLe Monnier crater at 25.85 degrees N, 30.45 degrees E.
After landing, theLunokhod 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 theLuna 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 thelunar 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 theradiators. The following day, May 10, controllers saw the internal temperature ofLunokhod 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 MarsOpportunity rover exceeded it after having traveled over 40 km (25 mi).[12][13]
Lunokhod 2 continues to be detected bylunar laser ranging experiments and its position is known to sub-meter accuracy.[14] On March 17, 2010, Phil Stooke at theUniversity of Western Ontario announced that he had locatedLunokhod 2 inNASALunar Reconnaissance Orbiter (LRO) images,[15][16][17] 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 asLunokhod 2 turned around), and the LRO LROC team identified the correct location of the rover in March 2012.[5][18] ExcellentLunokhod 2 images from LROC were published by Mark Robinson on SESE site of ASU.[19]
Ownership ofLunokhod 2 and theLuna 21 lander was sold by theLavochkin Association for $68,500 in December 1993 at aSotheby's auction in New York.[17][20] (The catalog[21] incorrectly lists lot 68A asLuna 17/Lunokhod 1).
The buyer was computer game entrepreneur and space touristRichard Garriott (son of the astronautOwen K. Garriott), who stated in a 2001 interview withComputer Games Magazine's Cindy Yans that:
Garriott later confirmed that he is the owner ofLunokhod 2.[17][23][24]
Richard A. Garriott has finally seen the item he bought 17 years ago for $68,500.
