# 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, /k/, /e/, and /o/. 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. As of 30 August 2024, no launch date has been confirmed.

## 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.

## Technical aspects

The messages and library will be encoded in glass-made radiation-resistant DVDs. Symbolic instructions in several formats will show the future finders how to build a DVD reader.
The satellite has enough capacity to carry a four-page message from each of the more than six billion (as of the original 2009 deadline) inhabitants on the planet. Once the satellite is launched, the messages will be made freely available on the web.
The satellite itself is a hollow sphere 80 cm in diameter. The sphere is engraved with a map of Earth and surrounded by an aluminium layer, a thermal layer and several layers of titanium and other heavy materials intertwined with vacuum. The sphere is resistant to cosmic radiation, atmosphere re-entry, space junk impacts, etc. For its first few years in orbit, KEO will sport a pair of wings 10 meters across that will aid in its spotting from Earth. As the satellite enters the atmosphere, the thermal layer will produce an artificial aurora to give a signal of the satellite's re-entry. The passive satellite will not carry any communications or propulsion systems. It was planned to be launched by an Ariane 5 rocket (which was discontinued in 2023, and replaced by Ariane 6) into an orbit 1,800 km high, an altitude that will bring it back to Earth in 500 centuries, the same amount of time that has elapsed since early humans started to draw on cavern walls.

## Timeline

| Year | Event | Description |
| 1994 | The KEO satellite is first conceived | French artist-scientist, Jean-Marc Philippe, comes up with the idea for the KEO satellite. |
| 1996 | Initial delay | The launch was delayed due to "restructuring of the French then European space industry (1996/1999)" |
| 1998 | Technical feasibility first demonstrated | |
| 1999 | Message collection starts | Messages began to be collected and an initial launch date is set for 2001. |
| 2001 | Launch delayed to 2003 | The recession in the worldwide space activity from 2000 to 2002 and the attacks on the World Trade Center on 11 September 2001 caused the launch to be further delayed. |
| 2003 | Launch delayed to 2006 | The reorganization of the French Space Agency and the failure of the qualifying launch of Ariane V pushed the launch date back to 2006. |
| 2005 | ESA signs off on technical feasibility | |
| 2006 | Launch delayed to 2007/2008 | In 2006, the launch was delayed again, due to "lack of enthusiasm of several partners due to the prolongations of the project". |
| 2008 | Jean-Marc Philippe died | Jean-Marc Philippe died on 12 November 2008. Before his death, he held a degree in geophysics and also worked as a painter. |
| 2008 | Launch delayed to 2010/2011 | The launch was delayed due to "restructuring of the data processing industry". |
| 2009 | Original end of message collection | Deadline for message collection was extended to the end of 2014. The contribution deadline was originally 31 December 2009, but as of 2014, it has been extended to end of 2014. |
| 2011 | Launch delayed to 2012 | Launch was delayed due to "armed conflicts and political conditions of the world" |
| 2012 | Launch delayed to 2013 | |
| 2013 | Launch delayed to 2015/2016 | |
| 2016 | Launch delayed to 2018/2019 | |
| 2018 | End of message collection | |
| 2019 | Planned launch | The KEO was previously planned to launch in 2019, but this did not happen. |

## Popular culture

* Life After People: Season 2 Episode 3, "Crypt of Civilization", mentions KEO as one of the last time capsules in the universe.