"We already know that the human immune system changes in space. It's not as strong as it is on the ground," explains Kundrot. "In one of the experiments, Mark and Scott will be given identical flu vaccines, and we will study how their immune systems react." Another experiment will look at telomeres—little molecular "caps" on the ends of human DNA. Here on Earth, the loss of telomeres has been linked to aging. In space, telomere loss could be accelerated by the action of cosmic rays. Comparing the twins' telomeres could tell researchers if space radiation is prematurely aging space travelers. .physorg-news-middle-block { width: 550px; height: 90px; } (adsbygoogle = window.adsbygoogle || []).push({}); Meanwhile in the gut, says Kundrot, "there is a whole microbiome essential to human digestion. One of the experiments will study what space travel does to [inner bacteria] which, by the way, outnumber human cells by 10-to-1." Other proposals are equally fascinating. One seeks to discover why astronaut vision changes in space. "Sometimes, their old glasses from Earth don't work," notes Kundrot. Another will probe a phenomenon called "space fog"—a lack of alertness and slowing of mental gears reported by some astronauts in orbit.

NASA to conduct unprecedented twin experiment Monday, April 14, 2014 @ 10:37pm