A set of related SF stories.  There are currently plot outlines for four stories.

The premise is that in the near future, the United Nations manages to pull together the authority and resources to launch twelve generational scientific exploration ships to investigate Earth-like worlds that have been identified around other stars.  Each ship is named after the individual star that is its goal (Alpha Centauri, Epsilon Eridani, Eta Carinae, and Tau Ceti), with the prefix ŜUN for "Ŝipo de la Unuiĝintaj Nacioj."

(One ship is currently listed as directed toward Alpha Centauri on the assumption that humanity would not be able to resist sending a ship there should they ever be capable of it.  However, it turns out, surprisingly, that there is a likely world around Proxima Centauri, so perhaps that should be changed.  The names of the ships are subject to change at any rate since apparently the names of the recognized constellations, and the use of the Greek letter designations, appears to have not yet been completely standardized in Esperanto.)

All the ships have the same initial baseline.  The technology is identical.  Formal protocols and standards are all the same.  The official language of the ships is Esperanto.  Each ship is staffed to fill the same necessary positions with respect to the running of the ship, the eventual research that will need to be conducted, and also community roles such as early-childhood education.  Ten women and ten men of reproductive age are selected, all doctors of their respective fields.

Reproduction of the next generation will of course be required and to maintain genetic diversity there is a sperm bank on board.  (When these stories were first conceptualized, freezing ova was not yet practiced, but if this story ever went to press that should probably also be included.)  Human psychology being what it is, the crew are expected to pair off and produce one "natural" child and one artificially-inseminated child per couple.  These children must all be born within a few years of each other and must have an even gender balance to make it easier to produce the generation following.  It is currently assumed that the initial protocols would call for the gender of the artificially-inseminated children to be screened somehow to ensure the correct balance for their generation, but other approaches are possible.

The stories themselves take place as the members of the third generation born on each ship are entering their twenties and are therefore being expected to take up the mission on their own behalf.  (The timing allows for the possibility of members of the original crew to still be alive if desired.)  The stories are intended to be a speculative study as to how the cultures on board the different ships would have evolved in that time.  It is assumed that there will have been unique linguistic changes, for example, despite each ship originating with the same strictly codified artificial language.

The plots generally relate to how the circumstances under which an individual grows up form a permanent influence not only on their behavior but on their ways of thought and general approach to the world.  And, of course, what becomes of individuals who, one way or another, do not happen to fit into that world scheme.

The ships also serve as a microcosm to explore issues that are as yet unresolved on the planet such as the consequences of uncontrolled population.  The final story includes a return to Earth and so involves what would (and would not) have changed there during the same time.

(One of the issues that was supposed to be specifically made irrelevent to most of the stories, however, was that of race.  Under the original concept, by the third generation the characters would all have been so racially mixed that it would presumably no longer be a factor.  If there are frozen eggs as well as sperm, however, the artificially-inseminated children would probably still have identifiable racial characteristics even if care were deliberately taken to give them mixed heritages.  So it can no longer be assumed that race won't ever come into it.)