Space is a harsh environment, wrought with intense radiation and temperature extremes, both of which can wreak havoc on electronics equipment and the human body. Myriad other dangers exist. Some of them, like reduced gravity, seem benign but are far from it.
Astronaut Scott Kelly’s long stint in space is helping NASA scientists and researchers learn more about all the potential side effects of living in a microgravity environment. (It’s not zero gravity like many people think, NASA scientists explain; rather, it’s reduced gravity or microgravity.)
Scientists are studying and measuring Kelly and comparing his physicality to that of his twin brother, also an astronaut but who stayed on Earth and serves as the control. They quickly learned that over nearly one full year in space, Kelly “grew” approximately two inches. That is, he measured two inches taller when he returned from the International Space Station (ISS) than when he left Planet Earth. Lack of gravity enabled spaces to develop between his vertebrae. This gain in height was only temporary; the expansion of his spine was almost immediately lost once he returned to Earth.
An unforeseen effect long-term microgravity had on Kelly involves skin sensitivity. Items in the ISS, including the astronauts’ uniforms and clothing, “float” around their bodies. This lack of contact with the skin greatly increased sensitivity, so much so that Kelly reported burning sensations all over his body when he moved.
Other effects of living in microgravity include bone loss, greater risk of kidney stones, muscle fiber shrinkage, problems with cardiac function, and problems regaining balance when back in Earth’s gravity. Kelly admits that going from Earth’s gravity to microgravity on the ISS is much easier than the reverse, and jokes that aliens might have it better than Earthlings.
The NASA study of Kelly’s physicality after his stint in space has only just begun, but it seems as though we’re on the cusp of learning a great deal about life in space. Since his return, Kelly has announced his retirement after serving as a U.S. Navy Captain, completing four space flights, and commanding the ISS on missions 26, 44, and 45. This mil/aero geek joins the ranks of many who are sorry to see him go, but thank him for his service. (Be sure to check out Kelly on social media, where he continues to post highlights of his life back on Earth, including the first rain and cannonball into a pool after returning.)