KEO

KEO is the name of a proposed space time capsule which was to have been launched in 2003 carrying messages from the citizens of present Earth to humanity 50,000 years from now, when it would re-enter Earth's atmosphere. Its name represents the three most frequently used sounds common to the most widely spoken languages today, , , and . Everyone was invited to contribute to the time capsule, and the organizers encouraged everybody to gather messages from children, senior citizens, and the illiterate so that every culture and demographic on Earth was represented. Moreover, the organizers were committed to not filtering the messages, stating "all the messages received, without undergoing any censorship, will be embarked aboard KEO." The launch has been delayed several times due to major geopolitical shakeups, including 9/11 and the restructuring of the ESA. In July 2025 it was announced on project site that KEO project would close without launching the satellite.

== Contents == Personal messages A sample of air A sample of sea water A sample of earth A diamond that encases a drop of human blood chosen at random with the DNA of the human genome engraved on one of its facets. An astronomical clock that shows the current rotation rates of several pulsars Photographs of people of all cultures "the contemporary Library of Alexandria", an encyclopedic compendium of current human knowledge.