In 1969, the Luna 15 spacecraft attempted to land on the Moon and become the first to return samples from the lunar surface to Earth, but it failed. Meanwhile, Apollo 11 (USA) successfully collected about 21.5 kg of lunar soil and rock.
The Luna Program of the Soviet Union began in 1958, even before the U.S. Moon program, Apollo, was established. The goal of the Luna program was to launch a series of spacecraft to the Moon, including both orbiters and landers. The ultimate aim was to bring lunar samples back to Earth.
Astronaut Buzz Aldrin examines lunar soil, with the Apollo 11 Eagle module visible in the distance on the right. (Photo: NASA).
From the outset, the Luna program faced many failures. In several launches, the spacecraft did not even reach Earth orbit. Some managed to achieve orbit but were unable to go further. Others attempted to reach the Moon but overshot their target. A few crashed onto the lunar surface. At that time, the Soviet Union did not publicly acknowledge these failures; thus, the number of Luna missions is less than the actual number of launches. For Luna 15, the actual number of launches was 31.
However, it is important to note that the Soviet Union’s failures were not entirely blameworthy. The initial missions of the United States’ Pioneer program, which started almost concurrently with Luna, had a similar failure rate. In fact, Luna 1, during its fourth attempt, became the first spacecraft to leave Earth orbit, although it did not reach the Moon. The Luna program achieved many milestones, including the first artificial object to reach the Moon, the first soft-landing probe on the Moon, the first artificial satellite of the Moon, the first spacecraft to photograph the far side of the Moon, and the first to send back close-up images of the lunar surface.
When it became known that Apollo 11, the crewed mission to the Moon, would launch on July 16, 1969, the Soviet Union expedited the launch of Luna 15. They aimed to be the first to bring lunar samples back to Earth.
Luna 15 launched from Earth on July 13, three days before astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins departed aboard Apollo 11. Luna 15 entered lunar orbit on July 17, three days ahead of the American spacecraft. However, the Soviet Union did not anticipate the ruggedness of the lunar surface. Instead of landing early, the mission control team spent valuable time studying and analyzing the lunar surface over the next four days.
As a result, on July 20, 1969, Apollo 11 made history as the first crewed spacecraft to successfully land on the Moon. Astronaut Neil Armstrong also became the first person to set foot on this celestial body.
At one point, the Luna 15 control team considered landing the spacecraft two hours after Apollo 11 touched down, to collect samples and return before the Americans. But once again, uncertainties regarding the terrain below delayed the landing. Meanwhile, the Apollo 11 astronauts walked on the Moon and collected about 21.5 kg of soil and rock.
Landing sites of Apollo 11 and Luna 15 on the Moon. (Photo: NASA).
Eventually, with less than two hours until Apollo 11 was set to lift off from the Moon, the Soviet Union decided to allow Luna 15 to land. By that time, the spacecraft had completed 52 orbits around the Moon. However, four minutes after descending, Luna 15 crashed into a mountainside, approximately 870 km from the Apollo 11 Eagle module on the Moon.
The Soviet Union kept the details of the mission secret from the United States, only sharing the trajectory to address NASA’s concerns that Luna 15 could interfere with radio signals if its orbit was too close to Apollo 11. NASA was informed that Luna 15 was an orbiter. It was not until the final moments, as the spacecraft began its descent, that astronomers realized it was attempting to land.
Luna 15 failed, but Luna 16 later succeeded, becoming the first robotic probe to land on the Moon and return samples to Earth. The sample returned was only about 101 grams, but it was still a remarkable achievement as it was accomplished using robotic machinery. Subsequent Luna missions returned larger samples and also deployed rovers on the Moon—another first.
