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| A Luna 10 launch cover postmarked in Tartu with a hand cancel on April 1, 1966, one day after the spacecraft’s launch. |
Luna 10 was a Soviet unmanned lunar-orbiter mission launched from Baikonur on March 31, 1966. It entered lunar orbit on April 3, becoming the first artificial satellite of the Moon and the first spacecraft to orbit another celestial body.
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| A Luna 10 lunar orbit cover postmarked with a red Moscow special hand cancel dated April 8, 1966. |
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| A Luna 10 lunar orbit cover postmarked with a black Kiev special hand cancel dated April 9, 1966. |
Luna 10 was designed to study the Moon and its surrounding environment. Its instruments measured the lunar magnetic field, gamma radiation, cosmic particles, infrared radiation, micrometeoroids, and gravitational field. The mission provided evidence of variations in the Moon's gravity associated with mass concentrations, or mascons, beneath the lunar maria.
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| A postcard featuring an illustration of the Luna 10 in lunar orbit, postmarked in Kaluga with a hand cancel on April 12, 1972. |
The spacecraft operated for nearly two months, completing 460 lunar orbits and transmitting data during 219 communication sessions. Contact ended on May 30, 1966, after its onboard power reserves were exhausted.
