Space travel causes DNA changes in astronauts' blood.
A new study shows that spaceflight changes astronauts' blood DNA. The August research examined blood from 14 space shuttle astronauts
The researchers found DNA mutations in blood-forming stem cells compared to previous samples, which could cause concern.
The mutations are worrying, but below the concern threshold, say the researchers.
Still, experts determined that astronauts should have annual blood screenings to detect abnormalities.
DNA mutations in astronauts show that spaceflight has more unintended consequences than we thought.
Spaceflight, like that used in NASA's space shuttle programme, posed a cancer risk.