Luna 21
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| Organization: | Soviet Union |
| Major Contractors: | GSMZ Lavochkin |
| Mission Type: | Planetary Science Lunar roving vehicle |
| Satellite of: | Moon |
| Launch: | January 8, 1973 at 06:55:38 UTC |
| Launch Vehicle: | Proton 8K82K + Blok D |
| Mission Highlight: | Landed lunar roving vehicle January 15, 1973, 22:35 UTC at 25°51' N, – 30° 27' E. |
| Mission Duration: | 146-days. End of mission June 3, 1973 |
| Mass: | 5,950 kg |
| NSSDC ID: | 1973-001A |
| Webpage: | NASA NSSDC Master Catalog |
| Orbital elements | |
|---|---|
| Semimajor Axis: | 6,467.8 km |
| Eccentricity: | 0 |
| Inclination: | 60° |
| Orbital Period: | 118 minutes |
| Apogee: | 100 km |
| Perigee: | 80 km |
| Orbits: | ~36 |
| Lunar Landing: | January 15, 1973, 22:35 UTC |
| Landing coordinates: |
25°51' N, – 30° 27' E. |
| Distance traveled: | 37,000 meters |
| Instruments | |
| Imaging system : | Lunar photography |
| X-ray spectrometer : | |
| Penetrometer : | Lunar surface strength |
| Laser reflector : | Lunar - earth distance |
| Radiation detectors : | Lunar radiation environment |
| X-ray telescope : | |
| Odometer/Speedometer : | |
| Visible/ultraviolet photometer : | |
| Magnetometer : | |
| Photodetector : | |
Luna 21 (Ye-8 series) was an unmanned space mission of the Luna program, also called Lunik 21. 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.
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 × 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 Le Monnier crater at 25.85° N, 30.45° E. The lander carried a bas relief of Lenin and the Soviet coat-of-arms.
Luna 21 carried the second successful Soviet lunar rover, Lunokhod 2, and was launched less than a month after the last Apollo lunar landing. After a midcourse correction the day after launch, Luna 21 entered orbit around the Moon on 12 January 1973. Parameters were 100 × 90 kilometers at 60° inclination. On 15 January, the spacecraft deorbited and, after multiple engine firings, landed on the Moon at 22:35 UT the same day, inside the LeMonnier crater at 25°51' north latitude and 30°27' east longitude, between Mare Serenitatis and the Taurus Mountains. Less than 3 hours later, at 01:14 UT on 16 January, the rover disembarked onto the lunar surface. The 840-kilogram Lunokhod 2 was 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 2 had already traveled further than Lunokhod 1 in its entire operational life. On 9 May, the rover inadvertently rolled into a crater and dust covered its solar panels, disrupting temperatures in the vehicle. Attempts to save the rover failed, and on 3 June, the Soviet news agency announced 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 of Luna 21), an American scientist had given photos of the lunar surface around the Luna 21 landing site to a Soviet engineer in charge of the Lunokhod 2 mission. 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
[edit] See also
| Preceded by Luna 20 |
Luna programme | Succeeded by Luna 22 |
| Luna programme |
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| Luna 1958A | Luna 1958B | Luna 1958C | Luna 1 | Luna 1959A | Luna 2 | Luna 3 | Luna 1960A | Luna 1960B | Sputnik 25 | Luna 1963B | Luna 4 | Luna 1964A | Luna 1964B | Cosmos 60 | Luna 1965A | Luna 5 | Luna 6 | Luna 7 | Luna 8 | Luna 9 | Cosmos 111 | Luna 10 | Luna 1966A | Luna 11 | Luna 12 | Luna 13 | Luna 1968A | Luna 14 | Luna 1969A | Luna 1969B | Luna 1969C | Luna 15 | Cosmos 300 | Cosmos 305 | Luna 1970A | Luna 1970B | Luna 16 | Luna 17 | Luna 18 | Luna 19 | Luna 20 | Luna 21 | Luna 22 | Luna 23 | Luna 1975A | Luna 24 | ||||
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