Increased cosmic radiation may thwart manned Mars missions
While countries including Russia, the US, Japan, China, and India
have declared sending humans to Mars in the coming decades a
priority, a study published in Space Weather, an American
Geophysical Union journal, found that such journeys could prove
extremely risky for astronauts due to higher levels of cosmic
radiation in the last few years.
Long-term exposure to cosmic rays, a form of high-energy radiation capable of penetrating even the protective aluminum shielding of a spacecraft, can damage organs and cause cancer.
The researchers found that it would take 400 days for 30-year-old men and 300 days for 30 year-old women to reach the maximum radiation exposure level during the last solar minimum which occurred in 2009. The study predicts that if radiation levels continue to rise, the number of days humans can spend in deep space will drop by a further 20 percent.
A space mission to Mars is expected to take roughly a year, so astronauts would risk exposing themselves to deadly rays.
The upsurge of cosmic rays, measured by a decrease in sun spots, is a result of dwindling solar activity. An active sun ensures a magnetic field which deflects cosmic rays away from our solar system. However, as the sun’s activity drops, more and more rays are allowed to whiz through our solar system unimpeded, posing potential health threats to astronauts.
The research suggests that the sun’s current cycle, the weakest in over 80 years, could be part of a long-term trend.
"Over time, it's become increasingly clear that the space environment is not returning to normal. There's been a sustained change in the way the sun is behaving,” the study’s lead researcher Nathan Schwadron of the University of New Hampshire, said in a press release.
While Schwadron does not completely rule out space travel, he
cautions that the study’s findings could limit and alter future
space exploration missions.
“While these conditions are not necessarily a showstopper for long-duration missions to the moon, an asteroid or even Mars, galactic cosmic ray radiation in particular remains a significant and worsening factor that limits mission durations,” he said.