To address FlameBoy's original writeup, there is already writing on the moon, and extensive archeological evidence of the two major wings of late 20th-century civilization, the Soviet Union and the United States of America.

If humankind does destroy itself, and a subsequent post-cataclysm advanced human civilization or other intelligent race arises (rats are pretty damn smart, and if we wipe ourselves out, it may only take a few million years for them to achieve sentience) and reach for the moon. (As any curious intelligent species must.) They will have incontrovertible proof that a previous civilization existed, as there is a wealth of information up there.

The Soviets sent the following “impact” missions:

  • Luna 2 - Sep 12, 1959
  • Luna 3 - Oct 4, 1959
  • Luna 5 - May 9, 1965
  • Luna 7 - Oct 4, 1965

These would only provide interesting crash-site craters and fragments, but of undoubtedly intelligent origin. They also sent the following landers:

  • Luna 9 - Jan 31, 1966
  • Luna 13 - Dec 21, 1966
  • Luna 16 - Sep 12, 1970 – this mission had an unmanned sample-taking robotic stage that returned to earth.
  • Luna 17 - Nov 10, 1970 – this mission contained an unmanned rover.
  • Luna 20 - Feb 14, 1972 – also a sample return mission.
  • Luna 21 - Jan 8, 1973 – another unmanned rover mission.
  • Luna 23 - Oct 28, 1974
  • Luna 24 - Aug 14, 1976 – sample return.

Any intelligent species finding these bits of Soviet jetsam would be able to determine quite a bit about their makers, and may even be able to decipher their language from the technical markings on pipes, wiring, and such.

The Americans sent many missions, as well. The major difference here is that 6 of the missions were manned:

  • Apollo 11 - Jul 16, 1969 – the first manned lunar landing.
  • Apollo 12 - Nov 14, 1969
  • Apollo 14 - Jan 31, 1971
  • Apollo 15 - Jul 26, 1971 - first mission to use a manned rover.
  • Apollo 16 - Apr 16, 1972
  • Apollo 17 - Dec 7, 1972

These missions provided any future archeologists with a wealth of ergonomic information from the lunar rover seats and control positions, the various tools (including many Hasselblad cameras) and instruments, and the astronaut’s jettisoned spacesuits and backpacks (the lunar missions threw away everything they didn’t need to return, to increase the weight of rocks they could bring back.)

There were also plaques attached to each lander. They not only included the signatures of the mission astronauts and the president (ironically, Richard Nixon is currently the only president guaranteed a near-immortal memorial in this fashion), but a representation of the earth, which would provide geographical information that may allow any researchers to make a rough estimate of the era the landings occurred, if they can plot the continental drift accurately.

Depending upon the technical achievements and paradigms of this putative future race, they may or may not learn new things from our leavings. However, they will learn they were not the first race to gaze at the moon and wonder.

A list of lunar missions can be found at:

This is also the case on Mars. The difference there is that Mars has weather, and eventually the things we left there could be buried and/or eroded.