NASA twin study explores body’s response to long space travel

NASA ASTRONAUT SCOTT KELLY (LEFT) AND HIS IDENTICAL TWIN, MARK. (PAT SULLIVAN/AP)

Final results from the twin study featuring astronauts Mark and Scott Kelly were just released, showing, for the most part, that biological changes from space travel return to normal within six months of returning to Earth. One of the most notable findings: During his 340-day stay in space, Scott Kelly had longer telomeres — the protective ends of chromosomes that shorten as we age — than his earthbound brother Mark, but the telomeres returned to their pre-flight length once he came back to Earth. He did, however, have a larger number of short telomeres, which could mean a heightened risk for age-related diseases.

The results of the study pave the way for doing the kind of research that’s necessary as NASA considers other long-duration space travel, including to Mars, the study’s authors said in a call with reporters.