Homo Exterra

A space race....

So I cheated... Homo Sapiens is the Genus and Species of the modern man. Exterra is a combination of 2 latin words ex (out of, from) and terra (earth, land, ground). When we move to space as a permanent habitat, we may have generations of people growing up in microgravity. A recent article suggested that bone loss from microgravity can become so severe for long trips that the astronaut may be unable to return home.

NASA has been studying bone loss to extend the active duty time of its astronauts as well as increase their level of comfort between extended trips (such as 6 months on the ISS). Here's their main concern as stated in the article:

Exposure to the microgravity environment of space causes astronauts to lose calcium from bones. This loss occurs because the absence of Earth's gravity disrupts the process of bone maintenance in its major function of supporting body weight.

Because of this, our first permanent settlement, not just an outpost, may be manned by generations of people who's bodies will be shaped much differently from our own or may just be too brittle to visit "Mother Earth" or Gaea, to borrow from Greek Mythology. Now, there are many stories where people have very dense or very light bone structure and can't handle a "normal" environment properly anymore. Do not be surprised if in the next generation, Homo Exterra are transmitting back to earth home sick letters looking for someway to experience their roots....