Astronauts face radiation threat on long Mars trip

LOS ANGELES, CA Using the radiation sensor aboard the NASA rover Curiosity, scientists estimated that a round-trip voyage would expose astronauts to about 662 millisieverts. That's similar to getting a full-body CT scan every five or six days for a year.

As plans for deep space exploration ramp up, radiation is a big concern. NASA aims to send a crew to orbit the red planet by the mid-2030s and private outfits are seeking volunteers for a Mars flight.

The latest finding, appearing in Friday's issue of the journal Science, only includes radiation exposure on a Mars flight. It doesn't include time spent on the Martian surface.