Luna 10

It was the first artificial satellite of the Moon.

Luna 10

Luna 10 mockup, Le Bourget (France)
Mission type	Lunar orbiter
Operator	GSMZ Lavochkin
COSPAR ID	1966-027A
SATCAT no.	02126
Mission duration	60 days
Spacecraft properties
Spacecraft type	E-6S
Manufacturer	GSMZ Lavochkin
Launch mass	1,583.7 kg
Dry mass	540 kg
Start of mission
Launch date	31 March 1966, 10:46:59 UTC
Rocket	Molniya-M 8K78M
Launch site	Baikonur, Site 31/6
End of mission
Last contact	30 May 1966
Orbital parameters
Reference system	Selenocentric
Periselene altitude	2088 km
Aposelene altitude	2738 km
Inclination	71.9°
Period	178.05 minutes
Lunar orbiter
Orbital insertion	3 April 1966, 18:44 GMT
Instruments
Magnetometer Gamma-ray spectrometer Five gas-discharge counters Two ion traps/charged particle trap Piezoelectric micrometeorite detector Infrared detector Low-energy x-ray photon counters

Luna 10 conducted extensive research in lunar orbit, gathering important data on the strength of the Moon's magnetic field, its radiation belts, and the nature of lunar rocks (which were found to be comparable to terrestrial basalt rocks), cosmic radiation, and micrometeoroid density. Perhaps its most important finding was the first evidence of mass concentrations (called "mascons") — areas of high density below the mare basins that distort lunar orbital trajectories. Their discovery has usually been credited to the American Lunar Orbiter series.

Part of the E-6S series, Luna 10 was battery powered and had an on-orbit dry mass of 540 kg. Scientific instruments included a gamma-ray spectrometer for energies between 0.3–3 MeV (50–500 pJ), a triaxial magnetometer, a meteorite detector, instruments for solar-plasma studies, and devices for measuring infrared emissions from the Moon and radiation conditions of the lunar environment. Gravitational studies were also conducted.

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  Replica of Luna 10 space probe, K. E. Tsiolkovsky Museum of the History of Cosmonautics
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  Luna 10 model (suspended), Memorial Museum of Cosmonautics

Luna 10 launched towards the Moon on 31 March 1966 at 10:48 GMT.

After a midcourse correction on 1 April, the spacecraft entered lunar orbit on 3 April 1966 and completed its first orbit 3 hours later (on 4 April Moscow time). A 245-kilogram instrument compartment separated from the main bus, which was in a 350 x 1,000-kilometre orbit inclined at 71.9° to the lunar equator.

Luna 10 operated for 460 lunar orbits and performed 219 active data transmissions before radio signals were discontinued on 30 May 1966.

The spacecraft carried a set of solid-state oscillators that had been programmed to reproduce the notes of "The Internationale", so that it could be broadcast live to the 23rd Congress of the Communist Party of the Soviet Union. During a rehearsal on the night of 3 April, the playback went well, but the following morning, controllers discovered a missing note and played the previous night's tape to the assembled gathering at the Congress — claiming it was a live broadcast from the Moon.