Embryo space colonization is a

theoretical A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may be ...

space colonization Space colonization (also called space settlement or extraterrestrial colonization) is the use of outer space or celestial bodies other than Earth for permanent habitation or as extraterrestrial territory. The inhabitation and territor ...

concept that involves sending a robotic mission to a habitable

terrestrial planet A terrestrial planet, telluric planet, or rocky planet, is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun: Mercury, ...

dwarf planet A dwarf planet is a small planetary-mass object that is in direct orbit of the Sun, smaller than any of the eight classical planets but still a world in its own right. The prototypical dwarf planet is Pluto. The interest of dwarf planets to ...

minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...

natural satellite A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are often colloquially referred to as ''moons'' ...

transporting frozen early-stage human

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

s or the technological or biological means to create human embryos. The proposal circumvents the most severe technological problems of other mainstream interstellar colonization concepts. In contrast to the

sleeper ship A sleeper is a person who is sleeping. Sleeper may also refer to: Arts and entertainment Characters * Sleeper (Marvel Comics), a Nazi German robot utilized by the Red Skull in Marvel Comics * The Sleeper (Wild Cards), a character in the Wild Ca ...

proposal, it does not require the more technically challenging 'freezing' of fully developed humans (see ''

cryonics Cryonics (from el, κρύος ''kryos'' meaning 'cold') is the low-temperature freezing (usually at ) and storage of human remains, with the speculative hope that resurrection may be possible in the future. Cryonics is regarded with skeptic ...

)''.

Various concepts

Embryo space colonization concepts involve various concepts of delivering the embryos from

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's sur ...

to an

extrasolar planet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...

around another star system. * The most straightforward concept is to make use of

embryo cryopreservation Cryopreservation of embryos is the process of preserving an embryo at sub-zero temperatures, generally at an embryogenesis stage corresponding to pre-implantation, that is, from fertilisation to the blastocyst stage. Indications Embryo cryopreser ...

. Modern medicine has made it possible to store frozen embryos in various low-development stages (up to several weeks into the development of the embryo). * The technologically more challenging but more flexible scenario calls for just carrying the biological means to create embryos, that is various samples of donated

sperm Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, ...

and

egg cells The egg cell, or ovum (plural ova), is the female reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female gamete is ...

. * Self replicating machines could spread out to interstellar space, bring uploaded human minds with them and/or receive them via radio or laser transmission and build artificial electronic brains/bodies as needed. The uploaded humans can raise the children.

Mission at target planet

Regardless of the cargo used in any embryo space colonization scenario, the basic concept is that upon arrival of the embryo-carrying spacecraft (EIS) at the target planet, fully

autonomous In developmental psychology and moral, political, and bioethical philosophy, autonomy, from , ''autonomos'', from αὐτο- ''auto-'' "self" and νόμος ''nomos'', "law", hence when combined understood to mean "one who gives oneself one's ow ...

robot A robot is a machine—especially one programmable by a computer—capable of carrying out a complex series of actions automatically. A robot can be guided by an external control device, or the control may be embedded within. Robots may be ...

s would build the first settlement on the planet and start growing food. More ambitiously, the planet may be

terraformed Terraforming or terraformation ("Earth-shaping") is the hypothetical process of deliberately modifying the atmosphere, temperature, surface topography or ecology of a planet, moon, or other body to be similar to the environment of Earth to make ...

first. Thereafter the first embryos could be unfrozen (or created using biosequenced or natural

and

as outlined above). In any event, one of the technologies needed for the proposal are artificial uteri. The embryos would need to develop in such artificial uteri until a large enough population existed to procreate by natural biological means.

Comparison to other interstellar colonization concepts

* Proposals of

s and

generation ship A generation ship, or generation starship, is a hypothetical type of interstellar ark starship that travels at sub-light speed. Since such a ship might require hundreds to thousands of years to reach nearby stars, the original occupants of a ge ...

s require very large spacecraft to transport humans, life support systems and other equipment or food as well as an even larger propulsion system for a long period in time. Even optimistic proposals would require such a major effort for such ships that the resources required on Earth would involve a large part of mankind devoted to the mission or would even exceed available resources. In contrast, an EIS would have feasible small dimensions in the range of today's

spacecraft A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, ...

, as the most important "cargo" would not need much space or weigh very much. *

Sleeper ship A sleeper is a person who is sleeping. Sleeper may also refer to: Arts and entertainment Characters * Sleeper (Marvel Comics), a Nazi German robot utilized by the Red Skull in Marvel Comics * The Sleeper (Wild Cards), a character in the Wild Ca ...

proposals call for freezing adult humans. While there is research into

hibernation Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It mos ...

, the complexity of a living fully developed human body may make the sleeper ship proposals much more difficult. * While sleeper ships and generation ships would deliver to a prospective colony world a population that has undergone some degree of education, training, and socialization in areas reconcilable with those of the sponsor culture (e.g. historical, scientific, and technical education, language acquisition, an understanding of the original mission and broader cultural norms), individuals who are born into colony worlds through embryo space colonization would initially lack this education.

Difficulties in implementing the concept

Like every proposal for interstellar colonization, embryo space colonization depends on solutions to still-unsolved technological problems. Some of these are: * Robotics: Whether it will be possible to develop fully autonomous robots that can build the first settlement on the target planet and raise the first humans, is unclear. Because the initial probe must be maximally compact, the industrial robots that build the habitat would themselves have to be built autonomously from local materials. Though such technology does not yet exist, there are strong economic incentives to develop it, which are unrelated to space colonization. * Artificial Intelligence: It would be challenging to create an

artificial intelligence Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animals and humans. Example tasks in which this is done include speech ...

that could serve as an adequate artificial parent and successfully raise human children who have no contact with other human beings. Its design would have to include strategies for the transmission of terrestrial culture and language, as well as the prerequisites for healthy psychological functioning, to persons who cannot interact with Earth. * Artificial Uterus: Artificial wombs exist today but they are not available for full-term development of fetuses. Human embryos have been successfully grown in artificial uteri for 13 days. There is a 14-day rule, codified into law in twelve countries, preventing human embryos from being kept in artificial uteri past 14 days. * Long-duration computers:

Computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations ( computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These prog ...

hardware would need to function reliably over long periods of time, in the range of several thousands of years. * Propulsion: Furthermore, a

propulsion Propulsion is the generation of force by any combination of pushing or pulling to modify the translational motion of an object, which is typically a rigid body (or an articulated rigid body) but may also concern a fluid. The term is derived f ...

system would be required that could accelerate the EIS to a high speed and slow it down again upon nearing the destination. Even assuming a speed one hundred times faster than any of today's space probes and a target planet within a couple of hundred light years would lead to a journey lasting several thousand years. * Exoplanet found: Finally this depends on the existence of an

exoplanet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...

qualifying for colonization within a reachable distance. Current or future science missions like the Hubble, James Webb, or

TESS Tess or TESS may refer to: Music * Tess (band), a Spanish pop band active from 2000 to 2005 * TESS (musician), a UK musician Film and theatre * ''Tess'' (1979 film), a 1979 film adaptation of '' Tess of the d'Urbervilles'' * ''Tess'' (2016 fil ...

space telescopes may very well yield results for this requirement in the near future. Further unknowns that affect the feasibility of embryo space colonization are: * Biological: Will genetic material survive intact on a space mission that could potentially last centuries? Exposure to

cosmic rays Cosmic rays 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 Solar System in our ...

is known to irreparably damage DNA. What other symbiotic lifeforms does a human need to live a healthy life? For example,

gut flora Gut microbiota, gut microbiome, or gut flora, are the microorganisms, including bacteria, archaea, fungi, and viruses that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the gut m ...

and many other species of microorganisms may be necessary for proper biological and immunological functioning. Babies normally acquire these from their mothers and the wider environment, but this would not be the case for embryos in colonization ships. * Ethical: In addition to the question of whether it is technically feasible to raise children without human contact, there is the further question of whether this is morally permissible. It is found to be unethical to deliberately create children that will grow up without parents, yet embryo space colonization requires this. Controversial value judgments would also need to be made about whose DNA should be the basis of the space colony. Should they be selected by some metric of merit, or randomly from the general population? Either choice presents ethical problems. Should the parenting AI firmly steer the children to maximize the chances of the colony's success, or should it accept the risk of allowing them significant autonomy? Which languages and cultural values should be transmitted to the colonists? Should they be raised according to some value system that exists on Earth, or create one that is somehow optimized? Are there truths that should be kept from them? The possibility of a new civilization that starts without a cultural legacy might appeal to cults that want their values to become a norm for an entire society. Is it permissible to allow them have their own embryo colonies, where the AI indoctrinates the colonists only in the cult's value system? The difficulty of answering these and other ethical questions may become a non-technological obstacle to embryo space colonization.

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