On April 3, 1966—50 years ago today—the Soviet Luna 10 satellite became the Moon's very first orbiter. Following close on the heels of Luna 9, the first spacecraft to land intact on the Moon and capture close-up pictures of its surface, Luna 10 represented a shift in luck for the beleaguered Luna spacecraft program, which had been on an epic losing streak at that juncture in the space race.
Kickstarted in 1959, the Luna program racked up many key spaceflight milestones within that first year. From sending probes into solar orbit to capturing the first images of the far side of the Moon, 1959 was packed with constant slam dunks for the Luna team.
But the program's luck reversed dramatically at the dawn of the next decade. From 1960 to 1965, Luna scientists attempted to launch 13 probes to the Moon, and every single one of them failed. This harsh turnaround was instrumental to the outcome of the space race, because it bought NASA adequate time to catch up with its rivals. By the time 1966 rolled around, the nations were almost evenly matched.
But before the US ultimately overtook the USSR with the Apollo program, the Luna program scored a few more important "firsts" with Luna 9 and 10. In contrast to the program's years of ill-fated soft-landing attempts, Luna 10 was only the Soviets' second shot at placing a satellite into lunar orbit. This achievement helped to counteract the dizzying freefall of the Luna program over the preceding five years, and helped to somewhat recover its reputation and image worldwide.
Short Luna 10 history. Video: International Astronomical Federation/YouTube
Relieved at the renewed success, the Soviet government milked the moment as much as possible. Luna 10 was intentionally scheduled to enter the Moon's gravitational pull in tandem with the 23rd Communist Party Congress meeting in Moscow.
"As it rounded the eastern edge of the Moon, Luna 10's transmitter went full on and relayed the bars of [the communist anthem] 'The Internationale'," which was "broadcast live by loudspeaker direct to the party congress over the static of deep space," according to Brian Harvey, author of the spaceflight history Soviet and Russian Lunar Exploration.
"It was a triumphant moment and the 5,000 delegates had good reason to stand and cheer wildly."
It was, however, a fabricated moment of celebration, a fact that would remain a secret for 30 years. The delegates were not listening to a live message from the orbiter, but a pre-recording from the previous evening.
"The radio engineers did not trust the live broadcast to work, but, as they later admitted, playing tricks on the Central Committee was a dangerous game and the truth could only be safely revealed in the 1990s when the Central Committee itself was no more," writes Harvey.
Regardless of these conspiratorial beginnings, Luna 10 genuinely lived up to the high expectations that had been placed on it. It completed 460 orbits around the Moon before its transmitters ran out of batteries on May 30, 1966. Over the course of those two months, the orbiter sent 219 messages back to Earth detailing valuable data about the Moon's magnetic and gravity fields, micrometeorite impact rate, surface composition, and atmosphere (or lack thereof).
The current whereabouts of the orbiter are unknown, but odds are it crashed into the Moon decades ago. Its legacy as first artificial satellite of Earth's natural satellite, however, remains intact 50 years on.