Round trip to Mars would push radiation safety limits

"Is your face red from all this Mars dust, or is it the gamma-rays?"

NASA

Although a private effort hopes to send some people on a one-way trip to Mars, chances are good that the first people to reach the red planet will be government-supported astronauts who will be taking a round trip. But one of NASA's own instruments has just suggested that there might be an advantage to a one-way journey: a far lower dose of radiation.

The work takes advantage of a bit of hardware that NASA sent to Mars for a completely unrelated project: the radiation detector on the Mars Science Laboratory Curiosity. The Radiation Assessment Detector is actually two sensors; one tracks radiation via the energy it deposits in silicon, and the other watches for flashes of light that occur as radiation travels through a hunk of plastic. Agreement between the two sensors is used to determine the amount of radiation the detector is receiving.

The hardware is meant to sample the radiation environment on Mars (which also has significant implications for future exploration). But a large team of scientists realized that its travel to Mars provided a glimpse of the sorts of exposures crew members might receive during their journey through interplanetary space to Mars.