The Ecumene, while very interested in the idea of inhabiting many planets, generally does not habitiform planets beyond making unintrusive and local changes. The standard methodology for inhabiting a planet whose climate is incompatible with one's biology is instead bodily acclimatization, by a variety of methods.
The Ecumene does not generally have the will to use the technology required for full transhumanism, finding the concept somewhat distasteful- but it does accomodate for the ability to transform one's body to live in environments very different from the one their body was initially capable of surviving. Even for smaller changes this is a gradual process- teaching the body and mind to use organs and limbs that function differently than expected is a task considerably beyond teaching them to use new prosthetic limbs. The most extreme of these methods is somewhat analogous to the concept of creating an entirely new body and transplanting the mind, but at a much more gradual pace.
The transformation only involves electronic or robotic parts by choice, usually being an entirely biological and mental change. Because of this, large-scale acclimatizations are one of the only times during which a resident of the Ecumene may become sick- even changes as simple as the addition of organic filters may play havoc with the immune systems.
Starting around the year 4000, planetary habitiforming (and to a lesser extent habitation) fell precipitously out of vogue. While economics were very rarely a concern, a recent fiasco involving the accidental destruction of habitats belonging to especially charismatic species on several worlds brought the constant low-level controversy to a head. This combined with the relative abundance of habitable and lifebearing worlds of all kinds ignited several sets of debates, spawning movements such as the Protection Initiative.
One of these movements would cause a major shift in not only the ethics but also the technology and many other aspects of the Ecumene. This movement sought to make habitiforming one of several coequal options, rather than it being the path of least resistance to inhabiting some planets. They pioneered several generally new branches of science- not only the creation of now-common biological filters and other living technologies, and not only ways of getting brains to understand what they're connected to, but also made great leaps in dead-end technologies like whole-body transplants and changing the mind's own matrices.
These new technologies combined to form several entirely new methods for inhabiting worlds previously considered to require habitiforming- and others besides. Worlds that would normally be "subpar" for living- too cold or too hot, with mildly toxic atmospheres or soils, or even just with annoying gravity- could be made much more tolerable with techniques at worst as invasive as a minor anti-allergy injection. As the technologies developed, the range of worlds they could help people live on expanded massively- first worlds previously considered to require domed or floating habitats, then further to the surfaces of high-temperature or radioactive worlds. The techniques required to allow this diverged into three main paths- entirely covering the body, changing the body from the inside, and replacing parts of the body.
While acclimatizing to a new world is sometimes a process akin to constructing a biological skin-tight spacesuit atop one's body, and some formats function with scales and methods much like the pupatory metamorphosis of an insect, the very most common format of the process is a whole-body piecemeal method. Over a course of time comparable to other acclimatization methods, entire organs and body parts are switched out until the entire body (up to but usually only barely including the nervous system) is capable of functioning well in the desired environment. This can be done with one replacement per body part, but for complex changes usually includes at least one intermediary phase to allow a smoother change of function. The most common issue with this piecemeal method is that switching out body parts wholesale itself requires a period of acclimatization, and intermediate replacements are often weak in both the original and desired environment. Most simply deal with this- some even consider it envigorating when the final stage of replacements grow in and cause a noticeable return to their initial strength and endurance. Obviously many worlds require much more limited acclimatizations- the piecemeal method is less common for these, but some spend the time in transit ensuring their bodies are tuned for minutiae like local metal concentrations in soil.
As an example, for a trip from a low-temperature garden world like Artay to a thick-atmosphere carbon dioxide greenhouse like its inward neighbor one might acclimatize like this. First adjusting to one of Artay's hottest deserts, then travel inward and acclimatize to the carbon dioxide atmosphere (or else get a relatively simple biological scrubber), descending slowly to improve functionality at progressively higher temperatures and pressures. Such a process, while intensive, lasts a relatively short time- that full change might take just two months for someone taking it an average pace. In the Ecumene, changes like this- while not necessarily commonplace- fit very easily in the amount of free time available to any resident.
Generally this process conforms to the overall body format of the initial body, with further changes in bodyplan usually reserved for a year or more after the initial acclimatization. It is much easier to change to survive in a thick nitrogen-methane atmosphere than to do that and also become a centaur at the same time. As a result, much of the population of the Ecumene that is humanoid will remain humanoid for a long while before changing body format or internal senses. Such large changes are also generally not necessary for a visit- spacesuits, biological or otherwise, can accomodate that; and a courteous host should be able to find something one can eat that is at least stable in both environments.
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