Manned missions to Mars could put astronauts at risk of leukaemia

Nasa aims to carry out a manned mission to Mars in 2035, while private company Space X owned by Elon Musk has announced its aim to put humans on Mars by 2026. Now, thanks to a study conducted by Nasa, more is known about what toll the three-year voyage to Mars will take on the humans chosen to take on the pioneering mission.

Nasa recently funded a study that used human stem cells transplanted into mice to measure the effects of deep space radiation, led by researchers at the Wake Forest Institute for Regenerative Medicine.

The findings suggest that radiation encountered in deep space travel, believed to be one of the most unsafe aspects of a journey to Mars, could increase the risk of leukaemia in humans.

The study involved exposing hematopoietic stem cells (HSCs) of healthy astronauts - aged 30-55 years - to radiation that would be encountered in deep space, namely protons and iron ions. HSCs are responsible for producing blood cells that transport oxygen, fight infection, and remove harmful cells from our system. Researchers focused on two specific types of radiation – simulated solar energetic particles (SEP), and galactic cosmic ray (GCR) radiation.

HSC-implanted mice appeared to develop leukaemia when subjected to GCR radiation, demonstrating that exposure affects cells at stem cell level. The study also found that blood cell production was reduced by 60-80%, say the scientists.

Mutations that occurred in the cells during tests could dramatically affect the immune system and translate into anaemia and cancers during prolonged space travel, according to Christopher Porada, expert on regenerative medicine and senior researcher on the project. “We found that genetic damage to HSCs directly led to leukemia. Radiation also altered the ability of HSCs to generate T and B cells, types of white blood cells involved in fighting foreign invaders like infections or tumor cells.”

The findings did not inspire confidence in deep space travel, as previous studies suggest that conditions of weightlessness and microgravity also affect the immune system, even in low earth orbit.

As part of the project, the researchers are testing a dietary supplement that could potentially protect astronauts from the detrimental effects of cosmic travel.

Nasa is also currently exploring the effects of isolation and confinement, hostile and closed environments, as well as distance from earth in order to make future space missions as safe as possible.