You could record where the reflectors are and how many you observe today. Then, assuming your progeny hold sufficient trust in you and your memory, your childre

You could record where the reflectors are and how many you observe today. Then, assuming your progeny hold sufficient trust in you and your memory, your children would be able to compare your notes with their future notes, by which time NASA will have placed additional retroreflectors on the moon. The difference would be proof that we've been to the moon.