In a setting where hundreds of scientists and engineers from around the world embark on an international mission to colonize a distant Earth-like planet (the ethics thereof are out of the scope of this question), and the unifying language happens to be Esperanto, to what extent, in what manners, and at what rate can/would the language deviate or evolve differently from terrestrial Esperanto over time? My intent is not necessarily to create another language or dialect that has branched from terrestrial Esperanto, but to illustrate the effects that may occur when a language evolves separately from its parent in such a setting.
Firstly, I would imagine that such an "international" civilization would be an interesting "superculture", but I'm not sure what effect it would have on a language like Esperanto, which is already intended to be pretty unifying.
Secondly, the setting is explicitly disconnected from terrestrial civilization, and nearly everyone here is a scientist, engineer, or a child thereof. What effects might this have?
Thirdly, and most obviously, neologisms, idioms, and quirks that have developed since their departure from Earth obviously won't appear in their setting (unless they somehow coincidentally come up with the same things). As a slightly more meta question, to what extent can I, as a writer, make their language a little different? Surely, I'm not going to start arbitrarily making up new words or messing with the grammar, but perhaps introducing little nuances, such as, for example (and this is just an example), the tendency for adjectives to come after nouns as opposed to the norm on Earth. Ideally, this extraterrestrial Esperanto should still be valid terrestrial Esperanto.
Another concern I have is to what extent linguistic and cultural nuances can differ in terms of what could realistically happen. For example, in this setting and culture, all things, animate or inanimate, are considered objects (in analogy to recognizing both humans and non-humans animals as animals). If the gender-neural pronoun "ri" was not conceived prior to their departure, they perhaps could have used "ĝi" (the pronoun meaning "it") as the notion of "object" differs from what it may imply in a language like terrestrial English (i.e. "humans aren't objects").
Given that the scientists departed at around 1995, and it is now 2047, to what extent could the language have evolved? What could happen in the future, given complete isolation and completely separate societal and cultural development from Earth in such a setting?
50 years is quite short, as mentioned by John. It is this short in timespan because I did not want to situate the setting too far in the future. I now ask instead how long it would take for a non-negligible amount of differences to develop, and what could possibly happen in such a timespan (in addition to the above, but much further in the future than a measly 50 years).