Astronauts Mark and Scott Kelly are the only siblings who have both traveled in space. The fact that they are identical twins makes them unique test subjects for a new scientific experiment being conducted by NASA to study the effects of long term space travel on the human body.
Jacob Aron is a technology reporter for New Scientist and creator of the website, “Just a Theory.” He wrote about the Kelly brothers “Twin Mission” in the latest issue of New Scientist magazine.
