Space travel is a hazardous endeavour at the best of times, but a new study suggests that astronauts on any future manned space mission to Mars are also more likely to get cancer, due to radiation exposure during the flight.

The team of scientists led by Rebecca Williams from the Planetary Science Institute in Tucson, Arizona gathered data on the radiation hitting NASA’s Mars rover, Curiosity, following its launch in November 2011.

Radiation dosage is measured in units known as sieverts and experts estimate that an astronaut will have absorbed a total of 0.66 sieverts during a 180-day each-way mission to and back from Mars, mostly due to solar storms and high-energy cosmic rays.

The time spent on Mars during any potential mission was not considered in the calculations, which were published in the journal Science.

A cumulative dose of one sievert over an astronaut’s entire career is thought to increase the risk of developing fatal cancer by about 5 percentage points.

“This means that a mission is not impossible, but the issue has become more complicated,” study co-author and physicist Robert Wimmer-Schweingruber told dpa.

The radiation exposure from high-energy cosmic rays that come from outside the galaxy could be even higher under different circumstances.

“Previously we only had computer models but now we have real data telling us the level of radiation an astronaut would be exposed to on a journey to Mars,” explained Guenther Reitz from the German Aerospace Center DLR.

The bombardment measured by Curiosity during its journey come as no surprise to scientists.

“We are now able to provide to best possible estimate of radiation exposure,” said Wimmer—Schweingruber.

Naturally uncertainties remain as solar activity cannot be predicted with total accuracy, but the study does indicate to scientists where they need to invest more time in research before it is possible to launch a manned mission to Mars.

The results show that the development of more powerful rocket engines is essential. Any reduction in journey time would reduce the associated health risk.

By contrast, it is considered practically impossible to significantly shield the astronauts, because lead and other metals used in barriers would be too heavy.

It is now accepted that any astronauts embarking on a space mission to Mars will face a higher risk of contracting cancer.

However according to Wimmer-Schweingruber, smokers still face a higher chance of developing lung cancer than astronauts do. NASA is actively working on a manned flight to Mars, with 2030 touted as a realistic date for any potential mission.

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