Breaking Down Ionizing Radiation

Humans haven’t travelled further than low Earth orbit since 1972.

Take that in, it’s been 51 years since we’ve travelled past Earth’s orbit.

I’m sure you’re wondering why. Well, there are a lot of reasons why: rocket issues, cost, and the medical effects on humans.

Being in space is, medically, really bad for humans. The lack of gravity, lack of oxygen and abundance of ionizing radiation hurts us.

To deal with the lack of gravity and oxygen, we have solutions such as artificial gravity and water electrolysis. However, we currently don’t have a solution to deal with ionizing radiation, which kinda messes up our travelling and colonising space plans :/

What is ionizing radiation?

Let’s start from the basics: what is ionizing radiation?

Ionizing radiation is a form of energy that acts by removing electrons from atoms and molecules. It’s invisible and passes straight through us without us even knowing!

Have you ever seen those movies where the main character gets blasted by the villain's powers? Ionizing radiation is like that blast, except we can’t see it or realise that it has hit us until it's too late.

Person getting blasted by ray of powers

Ionizing radiation is much more harmful than non-ionizing radiation, which has a significantly less amount of energy and we face more often on Earth. Ionizing radiation is more to the right of the electromagnetic spectrum, with electromagnetic radiations like x-rays and gamma rays.

A diagram of the electromagnetic spectrum with non-ionizing radiation to the left and ionizing radiation to the right

Thanks to our Earth’s atmosphere, we aren’t exposed to that much ionizing radiation. The average amount of ionizing radiation we are exposed to is 438–876 microsieverts every 6 months. For context, we need to be exposed to 400,000 microsieverts of ionizing radiation in a short amount of time to die and need to be exposed to 100,000 microsieverts of ionizing radiation to have a high risk of getting cancer. Everyone say “Thank you Earth’s atmosphere!”

In space, however, we get exposed to a lot more ionizing radiation. Spending 6 months in space can get you exposed to 50,000–2,000,000 microsieverts of ionizing radiation, depending on where you are.

Health issues

As mentioned earlier, being exposed to a lot of ionizing radiation can cause some pretty bad health issues.

You know how our DNA is in a double helix shape? Well, the helices are connected in the middle by hydrogen bonds.

A diagram of how our DNA looks, the dots representing hydrogen bonds.

A hydrogen bond is an intermolecular force that forms an extremely strong dipole-dipole bond when a hydrogen atom bonds to a very electronegative atom. The hydrogen atom also needs to be near another electronegative atom that has a lone pair of electrons. You heard that right, a lone pair of electrons.

A diagram of a hydrogen bond; the red dashed line represents the hydrogen bond.

Remember who loves stealing electrons? Ionizing radiation! So when exposed to a lot of ionizing radiation, the electrons in our DNA’s hydrogen bonds get ripped out, forcing the hydrogen bond to collapse and in turn, our DNA to have a double-strand break.

Now, normally our body can heal damaged DNA, but double-strand breaks are really hard to heal. Sometimes, your body can’t heal the breaks at all or doesn’t heal those breaks properly. And a damaged DNA can lead to impaired cellular function, cell loss or cancerous cells, all things we do not want!

How do we protect ourselves?

Good news! On Earth, we face such small quantities of ionizing radiation that we don’t need to actively protect ourselves from it.

Bad news! In space, we need some kind of form of protection.

Even more bad news! We don’t have an adequate form of protection against ionizing radiation!

So when we talk about protection against radiation, we focus on what I like to call the 3 D’s:

The 3 D’s

1. Distance
   How close are you to the source of radiation? Can you move further away from it? Unfortunately, in space, we are in the source of radiation and can’t really move away from it, so increasing the distance is not a feasible method of protection.
2. Duration
   How long are you exposed to radiation? Can you reduce the time spent around the source? It takes us around 7 months to reach Mars. Unless we can increase the speed at which we reach places, it’s not possible to reduce the time spent around our radiation source. Plus, if we want to colonise or live in deep space, it’s impossible to reduce the time spent around the radiation source.
3. Defence
   What are you wearing? Is there any kind of shielding you can wear to defend yourself from the radiation? Something to prevent it from entering or reduce its intensity?

Shielding ourselves from ionizing radiation

Technically we have a suit that would protect us from ionizing radiation. Except that shield is made up of 6.6 feet of concrete or 1.3 feet of lead, which evidently, isn’t the most realistic.

Meaning, currently we don’t have a physical form of protection from ionizing radiation. Many researchers are looking into creating a physical form of protection or discovering a biological form of protection, but to date, nothing promising has been discovered or created yet.

Ionizing radiation is deadly and can cause detrimental damage to anyone exposed to it.

Unfortunately, until we figure out a way to protect our astronauts, it’s a really bad idea to send anyone out to deep space.

Sorry, Elon! Sorry, Bezos! I don’t think we’ll be colonising Mars anytime soon until this issue is fixed :/