DNA Explainer: What is space radiation and how does it affect humans?

NASA recently tweeted an image showing the harmful effects of radiation from sun on its telescopes which degrades their sensons. Not just for machines, the biggest hazard even for humans venturing into outer space is exposure to harmful radiation. 

Over time, even solar telescopes feel the effect of the Sun’s powerful radiation, which degrades their sensors. They must be calibrated to keep data accurate. Now, scientists are looking to artificial intelligence for new ways to keep their data on point. https://t.co/1AA3BIB8gq pic.twitter.com/y2mf8WZTOy

— NASA Sun & Space (@NASASun) July 31, 2021

Radiation is a form of energy. It is emitted in the form of rays, electromagnetic waves and/or particles. While some forms of radiation can affect us negatively, we have also leveraged it for different applications.  

We can see some forms of radiation, like visible light and also feel, like heat from infrared waves. Some other forms of radiation experienced on Earth are x-rays and gamma rays. We observe them using special equipment.

However, space radiation is different from what we experience on Earth.

What is space radiation?

As per NASA, space radiation comprises atoms with bare nucleus, travelling in interstellar space at speeds close to the speed of light. These are particles that are released during solar flares or are trapped in the magnetic field of the Earth. Then there are galactic cosmic rays - high-energy particles that come from outside our solar system.

Radiation is of two types, non-ionizing radiation like UV rays, which is harmful but can be kept out using protective material, and the more dangerous ionizing radiation.

Who is at risk?

Earth’s atmosphere and magnetic field protect us from full impact of space radiation. Going to the edge of space, as our billionaires did, is fine. Astronauts in the ISS too. But venturing out of the Low Earth Orbit (LEO), radiation sickness poses significant risk to astronauts. There is also increased lifetime risk for cancer, central nervous system effects, and degenerative diseases, as listed by NASA. Almost all of our man-made equipment lies in the LEO.

Space radiation is one of the biggest risks to astronauts’ health & we're studying it to help keep astronauts safe: https://t.co/Wi1DGiPXtD pic.twitter.com/OqFgUoxyML

— NASA (@NASA) September 26, 2017

Research has shown strong evidence that exposures to galactic cosmic rays (GCR) or solar particle events (SPE) leads to cancer and degenerative diseases are to be expected from galactic cosmic rays (GCR) or solar particle events (SPE) exposure.

How radiation causes damage?

Difficult to shield from, ionizing radiation is like an “atomic-scale” cannonball event. It moves through substances and alters them forever. This is called ionization. Radiation can penetrate through spacecrafts and the skin of astronauts, leaving behind significant damage.

The amount of radiation that an astronaut receives in space depends on 1) the atmospheric protection which depends on the altitude above the Earth; 2) number and intensity of solar flares which depends on the Solar cycle, especially during periods when there are numerous sunspots and, 3) as NASA states, individual susceptibility, an area where there is ongoing research.