Did they really land on the Moon?

The question is often phrased in the singular, as if there had been only one landing. There were six. Apollo 11 touched down on July 20, 1969; Apollo 12 did so on November 19 of that same year; Apollo 14, on February 5, 1971; Apollo 15, on July 30, 1971; Apollo 16, on April 20, 1972; and Apollo 17, on December 11, 1972. Apollo 13 never landed because of a malfunction, though it too returned with photographs. On every mission that did land, one crew member stayed in the command module, in lunar orbit, while the other two descended to the surface in the lunar module.

Twelve human beings have walked on the lunar surface, all of them during the Apollo program, between 1969 and 1972. Of those twelve, four are still alive: Buzz Aldrin, David Scott, Charles Duke and Harrison Schmitt. Their names appear on the list of moonwalkers published by NASA.

The six missions that landed returned nearly 400 kilograms of lunar samples. That material is the least spectacular and most solid part of the matter. Added to it are the experiments deployed on the surface, covering soil mechanics, meteoroids, seismology, heat flow, laser distance measurement, magnetic fields and solar wind. Among them was the Apollo 11 retroreflector, a square 46-centimeter aluminum panel holding one hundred fused-silica prisms, one of the laser reflectors that are still targeted from Earth today to measure the distance to the Moon with a precision of about two centimeters. The evidence, in this case, is not photographs: it is objects that can be touched and experiments that can be repeated.