Luna 21
 Luna 21 as seen from orbit by theLROin March 2010 | |||||||||||||||||||||||
| Mission type | Planetary Science | ||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Operator | Soviet space program | ||||||||||||||||||||||
| COSPAR ID | 1973-001A | ||||||||||||||||||||||
| SATCATno. | 6333 | ||||||||||||||||||||||
| Mission duration | 8 days (day of launch to day of landing) | ||||||||||||||||||||||
| Spacecraft properties | |||||||||||||||||||||||
| Spacecraft | s/n 204 | ||||||||||||||||||||||
| Spacecraft type | Ye-8 | ||||||||||||||||||||||
| Manufacturer | GSMZ Lavochkin | ||||||||||||||||||||||
| Launch mass | 5,700 kg (12,600 lb)[1] | ||||||||||||||||||||||
| Dry mass | 4,850 kg (10,690 lb) | ||||||||||||||||||||||
| Start of mission | |||||||||||||||||||||||
| Launch date | 06:55:38, 8 January 1973 (UTC)[1] | ||||||||||||||||||||||
| Rocket | Proton-K/D | ||||||||||||||||||||||
| Launch site | Baikonur81/23 | ||||||||||||||||||||||
| Orbital parameters | |||||||||||||||||||||||
| Reference system | Selenocentric | ||||||||||||||||||||||
| Periselene altitude | 90 km (56 mi) | ||||||||||||||||||||||
| Aposelene altitude | 100 km (62 mi) | ||||||||||||||||||||||
| Inclination | 60° | ||||||||||||||||||||||
| Moonorbiter | |||||||||||||||||||||||
| Orbital insertion | 12 January 1973 | ||||||||||||||||||||||
| Orbits | ~36 | ||||||||||||||||||||||
| Moonlander | |||||||||||||||||||||||
| Landing date | 22:35, 15 January 1973 | ||||||||||||||||||||||
| Landing site | 25°51′N30°27′E/ 25.85°N 30.45°E[2] | ||||||||||||||||||||||
| Moonrover | |||||||||||||||||||||||
| Spacecraft component | Lunokhod 2 | ||||||||||||||||||||||
| Landing date | 01:14, 16 January 1973 | ||||||||||||||||||||||
| Distance driven | 42 km (26 mi) | ||||||||||||||||||||||
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Luna 21(Ye-8 series) was anuncrewed space mission,and its spacecraft, of theLuna program,also calledLunik 21,in 1973. The spacecraft landed on the Moon and deployed the secondSovietlunar 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.
Mission[edit]
Luna 21carried the second successful Soviet lunar rover,Lunokhod 2,and was launched less than a month after the last Apollo lunar landing. TheProton-K/Dlauncher put the spacecraft into Earthparking orbitfollowed bytranslunar injection.On 12 January 1973,Luna 21was braked into a 90 × 100 km orbit about the Moon, at a 60° inclination. On 13 and 14 January, theperilunewas lowered to 16 km altitude. On 15 January after 40 orbits, thebraking rocketwas 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 inLe Monnier craterat 25.85° N, 30.45° E, betweenMare Serenitatis( "Sea of Serenity" ) and theTaurus Mountains.The lander carried abas-reliefofVladimir Leninand the Soviet coat-of-arms.
Less than three hours later, at 01:14 UT on 16 January, the rover disembarked onto the lunar surface. The 840 kilogramLunokhod 2was an improved version of its predecessor and was equipped with a third TV camera, an improved eight-wheel traction system, and additional scientific instrumentation. By the end of its first lunar day,Lunokhod 2had already traveled further thanLunokhod 1in its entire operational life. On 9 May, the rover inadvertently rolled into a crater and dust covered its solar panels and radiators, disrupting temperatures in the vehicle. Attempts to save the rover failed, and on 3 June, theSoviet news agencyannounced that its mission was over. Before last contact, the rover took 80,000 TV pictures and 86 panoramic photos and had performed hundreds of mechanical and chemical surveys of the soil. The Soviets later revealed that during a conference on planetary exploration in Moscow, 29 January to 2 February 1973 (that is, after the landing ofLuna 21), an American scientist had given photos of the lunar surface around theLuna 21landing site to a Soviet engineer in charge of theLunokhod 2mission. These photos, taken prior to the Apollo 17 landing, were later used by the "driver team" to navigate the new rover on its mission on the Moon
- Launch Date/Time: 1973-01-08 at 06:55:38 UTC
- On-orbit dry mass: 4850 kg
Present ownership[edit]
Luna 21andLunokhod 2,still on the Moon, were purchased byRichard Garriottin December 1993 at a Sotheby's auction in New York.
See also[edit]
- Lunokhod 2
- Lunokhod programme
- Timeline of artificial satellites and space probes
- List of artificial objects on the Moon
- List of missions to the Moon
References[edit]
- ^abSiddiqi, Asif (2018).Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016(PDF)(second ed.). NASA History Program Office.ISBN9781626830431.
- ^"NASA NSSDC Master Catalog - Luna 21/Lunokhod 2".Retrieved1 January2011.