Scientists may have underestimated the effect of cosmic rays on humans as they leave Earth’s atmosphere and are exposed to the deadly radiation.
The likes of SpaceX, Nasa and China have announced their desires to get humans to Mars, but that may not be realistic as a study on mice found that radiation from cosmic rays could be twice as potent as had been estimated.
Initial estimates suggest it would take humans around nine months to get to Mars.
During that time, astronauts would be constantly bombarded from radiation from the sun, whereas people on Earth are protected by the planet’s atmosphere.
However, there is no protection from the radiation in space.
Health scientist Frank Cucinotta and Eliedonna Cacaoat the University of Nevada Las Vegas re-examined previous studies of cosmic rays on mice and found that the rodents were two times more likely to develop tumours in space.
The scientists say that the increased risk of cancer is a result of how the cosmic ray damages DNA which then spreads to other DNA.
When cosmic rays hit cells, the DNA is damaged which subsequently gives off chemical signals that results in other cells mutating.
The duo say that previous studies have not accounted for this.
In their paper published in the journal Nature, they write: “Studies … are urgently needed prior to long-term space missions outside the protection of the Earth’s geomagnetic sphere.”
However, they do note that there are “significant differences” between mice and humans, and more research will need to be done into how people’s DNA is altered by cosmic rays.
Nasa has previously said that it aims to get the first humans to Mars somewhere between 2030 and 2040.
Elon Musk’s SpaceX has the financial clout to reach Earth’s next door neighbour and is aiming to get people to the Red Planet by around 2030, with the first people there being tasked with beginning to build a new civilisation.