KEO is the name of a proposed space

time capsule A time capsule is a historic treasure trove, cache of goods or information, usually intended as a deliberate method of communication with future people, and to help future archaeologists, anthropologists, or historians. The preservation of holy ...

which was to have been launched in 2003 carrying messages from the citizens of present

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

to humanity

50,000 50,000 (fifty thousand) is the natural number that comes after 49,999 and before 50,001. Selected numbers in the range 50001–59999 50001 to 50999 * 50069 = 11 + 22 + 33 + 44 + 55 + 66 * 50400 = 27th highly composite number * 50625 = 154, sm ...

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 The September 11 attacks, also known as 9/11, were four coordinated Islamist terrorist suicide attacks by al-Qaeda against the United States in 2001. Nineteen terrorists hijacked four commercial airliners, crashing the first two into ...

and the restructuring of the ESA. , no launch date has been confirmed.

*Personal messages *A sample of

air An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...

*A sample of

sea water Seawater, or sea water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximate ...

*A sample of

earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

diamond Diamond is a Allotropes of carbon, solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Diamond is tasteless, odourless, strong, brittle solid, colourless in pure form, a poor conductor of e ...

that encases a drop of human

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

chosen at random with the

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

of the

human genome The human genome is a complete set of nucleic acid sequences for humans, encoded as the DNA within each of the 23 distinct chromosomes in the cell nucleus. A small DNA molecule is found within individual Mitochondrial DNA, mitochondria. These ar ...

engraved on one of its facets. *An astronomical clock that shows the current rotation rates of several

pulsar A pulsar (''pulsating star, on the model of quasar'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its Poles of astronomical bodies#Magnetic poles, magnetic poles. This radiation can be obse ...

s *

Photograph A photograph (also known as a photo, or more generically referred to as an ''image'' or ''picture'') is an image created by light falling on a photosensitivity, photosensitive surface, usually photographic film or an electronic image sensor. Th ...

s of people of all

culture Culture ( ) is a concept that encompasses the social behavior, institutions, and Social norm, norms found in human societies, as well as the knowledge, beliefs, arts, laws, Social norm, customs, capabilities, Attitude (psychology), attitudes ...

s * "the contemporary

Library of Alexandria The Great Library of Alexandria in Alexandria, Egypt, was one of the largest and most significant libraries of the ancient world. The library was part of a larger research institution called the Mouseion, which was dedicated to the Muses, ...

", an encyclopedic compendium of current human knowledge.

Technical aspects

The messages and library will be encoded in glass-made radiation-resistant

DVD The DVD (common abbreviation for digital video disc or digital versatile disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any ki ...

s. 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 A vacuum (: vacuums or vacua) is space devoid of matter. The word is derived from the Latin adjective (neuter ) meaning "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressur ...

. The sphere is resistant to

cosmic radiation Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Sol ...

, 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 An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...

, the thermal layer will produce an artificial

aurora An aurora ( aurorae or auroras), also commonly known as the northern lights (aurora borealis) or southern lights (aurora australis), is a natural light display in Earth's sky, predominantly observed in high-latitude regions (around the Arc ...

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 Ariane 5 is a retired European heavy-lift space launch vehicle operated by Arianespace for the European Space Agency (ESA). It was launched from the Guiana Space Centre (CSG) in French Guiana. It was used to deliver payloads into geostationar ...

rocket (which was discontinued in 2023, and replaced by

Ariane 6 Ariane 6 is a European expendable launch system developed for the European Space Agency (ESA) and manufactured by a consortium of European companies, led by the prime contractor ArianeGroup. As part of the Ariane rocket family, it is operate ...

) 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

In popular culture

* ''

Life After People ''Life After People'' is a television series on which scientists, mechanical engineers, and other experts speculate about what might become of planet Earth if humanity suddenly disappeared. The featured experts also talk about the impact of h ...

'', Season 2 Episode 3, "Crypt of Civilization", mentions KEO as one of the last

s in the universe.

References

{{reflist

External links

KEO website
Proposed spacecraft Time capsules 1994 introductions

Contents

Technical aspects

Timeline

In popular culture

See also

References

Further reading

External links