1966

Luna 10

The Soviet Union launches Luna 10 from Baikonur

Luna 10 was the spare. The spacecraft the Soviet Union had meant to send failed on the way up and was announced to the world as Kosmos 111.

31 March 1966: a backup goes up

The Soviet Union launched Luna 10 from Baikonur on 31 March 1966 aboard a Molniya-M rocket.

It was not the spacecraft the programme had intended to fly. An earlier Ye-6S attempt had already failed, and that failure was announced under the cover name Kosmos 111. Luna 10 was the backup craft, and it went up in its place.

Launch was not arrival

Leaving Baikonur only put Luna 10 on a path to the Moon. Nothing about the launch could make it a lunar satellite: capture required a retrograde braking burn out at the far end of the trajectory, firing the engine backwards to shed speed rather than gain it.

So the launch bought a trajectory and a deadline. A course correction on 1 April refined the approach for the encounter three days after lift-off.

What 31 March made possible

On 3 April the braking engine fired at 18:44 UTC and the Moon captured the spacecraft, making Luna 10 the first human-made object to orbit a body other than Earth — a separate event, three days downstream of this one.

The first artificial satellite of the Moon was the one the Soviet Union had kept in reserve.

Sources

Researched 23 Aug 2026 6 sources 2 audit passes, 1 issue open Date corrected

How this was checked

Researched from the web into a fact sheet, rewritten from that sheet, then audited against it by a different model. How the pipeline works →

Date corrected. The research places this at 1966-03-31.

What the sources leave uncertain

The listed date has only year precision, but the mission's component dates are firmly established: launch on March 31 and lunar-orbit insertion on April 3, 1966.
The event wording combines two distinct milestones separated by three days. An article should state both dates rather than imply that Luna 10 entered lunar orbit at launch.