Apollo insurance covers

The Apollo insurance covers are autographed postal covers signed by the astronaut crews prior to their mission. The insurance covers began with Apollo 11 and ended with Apollo 16. The ability of astronauts to obtain much life insurance was limited, so they signed hundreds of postal covers before they left, on the presumption that they would become highly valuable in the event of their death. The crew would designate a trusted ally with the covers who would then have them cancelled at the Kennedy Space Center (KSC) post office on the day of launch and/or on the day of the lunar landing.

Apollo 11 insurance covers normally fetch the highest prices because it was the first lunar landing mission.

There are three varieties of the Apollo 11 covers, four of Apollo 12, two of Apollo 13, two of Apollo 14, one of Apollo 15 and one of Apollo 16. Some astronauts also left behind single signed covers for their families.

The two producers of the mission covers were The Manned Spacecraft Center Stamp Club in Houston, Texas (the MSCSC Covers) and a friend of the astronauts, Al Bishop (the "Bishop Covers"). Especially in the case of the MSCSC Covers, there are many of the exact covers that the stamp collectors also obtained through the club. These were also crew signed, but many after the mission, which makes them not an insurance cover. The essence of a true Insurance Cover is the fact that it was signed while in quarantine prior to launch and that it was one of those that were left behind for the crew families in the event of disaster. In order to be certain that a cover is a genuine Insurance Cover, it must originate from one of the crew members or their families. Ideally, the reverse of the cover should be certified by one of the crew.

Although flown artifacts from the Apollo missions are normally the most desirable objects for collectors, Insurance Covers have become highly popular because they truly display all that a collector would want from a mission; a beautiful design which normally included the mission emblem, a postal cancellation of the day of launch, authentic vintage signatures of the crew prior to the launch, and a certification attesting to its authenticity.

...
Wikipedia