Too much time in space is threat to astronauts’ health

Barry Wilmore outside the International Space Station
Barry Wilmore outside the International Space Station
NASA

Astronauts could be at greater risk of disease because time spent in space significantly hampers their immune systems, Nasa has found.

The cells that defend the body against illness change during long trips into space, raising serious health concerns for crew members.

The research will add to worries that Nasa’s plan to send a manned mission to Mars by 2030 could be stymied by mounting evidence that the year-long return journey would damage the explorers’ bodies irreparably.

Scientists at the space agency asked 23 astronauts doing stints aboard the International Space Station to take samples of their blood and send them back to Earth on relief vessels. The first samples were taken two weeks after the astronauts arrived, with further tests about three months and