A huge challenge faced in the pursuit of a mission to Mars is space radiation, which is known to cause several damaging diseases – from Alzheimer’s disease to cancer.
And soon, these problems will not just be exclusive to astronauts. Speculation over whether space tourism is viable is becoming a reality, with Virgin Galactic and SpaceX flights already planned for the near future. The former reportedly sold tickets for US$250,000.
But could questions over the health risks posed hinder these plans?
What is space radiation?
In space, particle radiation includes all the elements on the periodic table, each travelling at the speed of light, leading to a high impact and violent collisions with the nuclei of human tissues.
The type of radiation you would endure in space is also is different to that you would experience terrestrially. On Earth, radiation from the sun and space is absorbed by the atmosphere, but there is no similar protection for astronauts in orbit. In fact, the most common form of radiation here is electrochemical – think of the X-rays used in hospitals.
The sun is just one source of radiation astronauts face in space. Image: Pixabay
On the space station – situated within the Earth’s magnetic field – astronauts experience ten times the radiation that naturally occurs on Earth. The station’s position in the protective atmosphere means that astronauts are in far less danger compared with those travelling to the Moon, or even Mars.
Currently, NASA’s Human Research Program is looking at the consequences of an astronaut’s exposure to space radiation, as data on the effects is limited by the few subjects over a short timeline of travel.
Radiation poses one of the biggest problems for space exploration. Video: NASA
However, lining the spacecraft with heavy materials to reduce the amount of radiation reaching the body isn’t as easy as a solution as it is seems.
‘NASA doesn’t want to use heavy materials like lead for shielding spacecraft because the incoming space radiation will suffer many nuclear collisions with the shielding, leading to the production of additional secondary radiation,’ says Tony Slaba, a research physicist at NASA. ‘The combination of the incoming space radiation and secondary radiation can make the exposure worse for astronauts.’
As heavy materials cannot hamper the effects of radiation, researchers have turned to a more light-weight solution: plastics. One element – hydrogen – is well recognised for its ability to block radiation, and is present in polyethylene, the most common type of plastic.
A thick dust cloud called the Dark Rift blocks the view of the Milky Way. Image: NASA
Engineers have developed plastic-filled tiles, that can be made using astronauts rubbish, to create an extra layer of radiation protection. Water, which is already an essential for space flight, can be stored alongside these tiles to create a ‘radiation storm shelter’ in the spacecraft.
But research is still required. Plastic is not a strong material and cannot be used as a building component of spacecrafts.