As humankind ramps up efforts to send its first fleet of astronauts to Mars, research into the various effects of such a trip are being studied extensively, including the psychological state of those who travel and live on the Red Planet. It has been known that radiation levels on Mars are high, and as such radiation shields will be used to protect against its negative effects. Current research, however, shows that the risk of developing cancer is higher than currently acceptable for NASA astronauts.
In order to determine the levels of radiation astronauts would be exposed to on Mars from within a radiation-shielded spacecraft, NASA used the Radiation Assessment Detector on Curiosity rover. Such a tool is designed to provide valuable data on radiation and shielding efforts, to allow the agency's researchers to determine the effectiveness of different methods.
Said NASA's Associated Administrator for Human Exploration and Operations William Gerstenmaier: "As this nation strives to reach an asteroid and Mars in our lifetimes, we're working to solve every puzzle nature poses to keep astronauts safe so they can explore the unknown and return home ... we'll continue to make the advances we need in life sciences to reduce risks for our explorers. Curiosity's RAD instrument is giving us critical data we need so that we humans, like the rover, can dare mighty things to reach the Red Planet."
NASA has a career limit in place for the amount of radiation an astronaut can be exposed to, a measure in place to minimize the astronaut's chance of developing cancer as a result of the exposure. What the study conducted with RAD revealed was a possible radiation exposure level for Mars travelers that exceeds this limit, which means either new better shielding is needed or the lifetime limit needs to be increased.
A single Sievert measurement of radiation exposure represents a 5-percent increased risk of developing a fatal cancer, which is higher than NASA's 3-percent lifetime exposure limit. The average radiation exposure measured by RAD came in at 1.8 milliSieverts per day, most of which was not the result of solar activity. According to one researcher, this is equivalent to getting a whole-body catscan every 5 - 6 days.