Space, and Man’s Biggest Obstacle from Exploring It

Radiation- it’s a scary word to the most of us, and an even scarier word if you’re planning to explore the depths of space.

However despite it’s fear-inducing term, in most cases, we get exposed to radiation throughout our everyday life; but I’m not here to talk about most cases. Space industry leaders such as SpaceX and even NASA are now expressing their planetary ambitions, but it’s clear that we’ve now hit a large barrier in our way, deadly space radiation!

But before we dive in, what does all of this mean? Why should you care about space radiation, our solutions, and really anything about this topic?

As we move into a new century of exponential technological growth, you and I are living in an age where the dream of seeing humans living across our solar system is no longer just a cool movie or book plot, but a feasible reality. This future is unfolding right before us, and you and I may very well become a part of that future within our lifetime!

A step closer to exploring and conquering the depths of space, is a step closer to humans etching an undying mark in the stars; allowing us to live beyond the confines of one small blue ball in the middle of the black abyss.

What’s Space Radiation? How is it Different from Earth’s Radiation?

On Earth, we are exposed to radiation in our day to day lives, but it’s usually not significant to our health. The radiation we get exposed to day-to-day is fairly harmless, with the main exception being UV rays. (Wear sunscreen!)

When it comes to radiation exposure, we measure in Sieverts and Milisieverts (SV/mSV). On the average of a year, you and I will receive about 1–2 mSV; this is a natural level that we’re adapted to, and it is not of any concern. However when you are trying to explore the depths of space, that changes real quick to you being on the receiving end of 700–900 mSV annually. Even if you were to make it to say, Mars, you’d still get smashed with 400–500 mSV annually, due to Mars’ extremely thin atmosphere and very weak magnetosphere.

Radiation is energy on the move, and different types of radiation vary on what form that energy is in. On Earth, we experience all kinds of radiation under the electromagnetic spectrum. What makes radiation dangerous often times is its ionizing ability- how effective it is at knocking out electrons or protons from an atom, thus making it an ion.

Radiation’s ionizing ability is determined based on whether the radiation is high or low energy. In human tissue, high-energy radiation (Ionizing radiation) translates to cell and DNA damage, especially when it comes to chemical modules of the double helix becoming ions as a result of radiation hitting it. Note that just because something doesn’t have relatively high ionizing power, doesn’t make it any less dangerous for biological matter.

In space, we’re dealing with three types of ionizing radiation, one of which is utterly next level!

1. Van-Allen Radiation: This radiation is emitted from our own planet, and it proliferates below these extremely strong magnetic barriers around our planet, known as Van-Allen Belts. These belts of high energy magnetic fields protect us from the other two types of dangerous radiation.
2. Solar Particle Events: This is energy including but not excluded to UV rays, being released from solar storms and energy anomalies happening on our sun, with Solar flares and winds being the most prevalent examples. Sometimes this travelling radiation is so strong that it causes electromagnetic disturbance to our electric systems, acting as a solar EMP.
3. Galactic Cosmic Rays (GCR’s): These are the incredible live records of what’s been happening in our galaxy! GCR’s are mainly protons and other subatomic particles, which were released and propelled by supernova explosions. These particles are some of the fastest-travelling entities we know of, with average speeds ranging from 40–96% the speed of light!

Galactic Cosmic Rays- Cool but Very Deadly

Now GCR’s may sound incredible and super awesome (which they are), but they will mess you up in no time, should you be exposed to them. GCR’s are energy particles and nuclei that are travelling through space at insane speeds, and do so indefinitely until stopped by something!

However the problem is that with our current technology, any space flight outside the Van-Allen Belts would have exactly that happen. This insane amount of deadly radiation at such high speeds takes an incredible toll on your DNA.

Adding on, these deadly cosmic rays can even tear apart solid metal walls on spacecraft, and any other structure we may send out there.

GCR’s are actually an umbrella term for these travelling galactic particles, with 99% of such being pure nuclei forms of atoms throughout the periodic table, and 1% being electrons and other subatomic particles. This is incredibly important, as this means we’re dealing with predominantly heavier forms of radiation than the typical photons and waves that we’re often used to dealing with

This means that GCR’s have relatively low ionizing ability alone, but this is excluding their speed, momentum, and their ability to radiate the water in our own body. All of this give GCR’s a more than powerful punch on biological matter, such as our DNA…

What are Free Radicals, and What Can They Do?

GCR’s consist of the atomic nuclei of all different elements ranging in atomic mass, thus meaning we are dealing with heavy, bulky radiation with less ionizing ability than others. Although we don’t know much about GCR-specific health effects, we can estimate effects based on other nuclei-composed radiation, such as Alpha rays. An observed point of major damage comes from when heavy nuclei radiation strikes off an electron in the hydroxyl ions within our body’s water, turning these ions into Hydroxyl Free Radicals.

Free radicals are defined as uncharged particles with an unpaired electron, thus making them highly reactive in a nature. When a Hydroxyl-based free radical is formed inside our body via radiation exposure, the radical will quickly look for a reliable source to match its unpaired electron.

This source oftentimes is our own DNA, where the radical will quickly absorb an electron directly from one of the DNA’s nucleotides. We also noticed that the slower a radioactive particle is in this context, the more time it has to interact with our DNA, thus making it more damaging for DNA./

This stealing of an electron by the radical, now creates an ion within the DNA structure. The indirect ionizing of DNA then can lead to breaks in bonds between the different double helix building blocks; single strand our double strand breaks.

Depending on the severity of the break or other form of DNA damage, our bodies’ DNA repair system may or may not be able to accurately repair and replace this damaged DNA. This can then lead on to many more consequences such as incorrect protein synthesis, which in turn can kickstart the development of cancerous tumors.

Stopping GCRs- RXF1 (Polyethylene)

Although officially we do not know a singular way to completely protect against GCR’s yet, we’ve discovered a few solutions to partially fix our problem! Hydrogen based materials such as polyethylene (Yes, the plastic) may be one of our solutions to GCRs.

Being a single proton/neutron element, Hydrogen is being experimented as a “fighting fire with fire” solution to our cosmic ray problem.

Hydrogen based materials may serve as an effective protection against GCR’s. With the protons and neutrons for all nuclei being almost the same size, Hydrogen nuclei can be simple and abundant atomic meat-shields for our needs.

Polyethylene is the primary plastic we use in our day-to-day products, like shopping bags and many different bottles. It’s a hydrogen based fabric which so happens to be a material that scientists know to be a good radiation shield, light, readily available, and physically flexible in form!

When addressing our needs for a space material, regular polyethylene theoretically fulfills the radiation problem. Polyethylene can deflect solar flares 50% and GCR 15% more effectively than our current aluminum materials. However speaking, simulations still has shown little significant improvement between the biological risks of humans in a Polyethylene spacecraft, and an aluminium spacecraft. All this means we have a lot more research to do on GCR biological effects, as well as beefing up the radiation fragmenting abilities of polyethylene.

However polyethylene alone isn’t strong enough to get us to space, and this is where researchers have made a beefed up version: RFX1. Having 3X the tensile strength at 1/2 the weight of aluminium, RFX1 can serve as a logistical and physical asset for the production of the next manned space exploration missions!

But before radiation even hits our spacecraft, why not try deflecting or stopping it before having to worry about it coming in contact?

Stopping GCRs- Spacecraft Magnetospheres

Just 500km above you, the inner layer of the Van Allen belts holds charged particles from mostly solar winds, using the Earth’s magnetic field to trap them in orbit. These solar wind particles are a mix of alpha particles, protons, and electrons, all protecting our planet from deadly GCR’s and ionizing Solar UV radiation.

Above that is the outer layer of the Van Allen Belt; our front line shield which is being pummeled over and over by cosmic rays and solar radiation. This shield is constantly changing; building and losing layers of itself as it gets pummeled by cosmic rays.

We can thank the teamwork of both these radioactive mediums for keeping us from becoming radioactive space dust! But this raises the question: Could we do the something similar for our spacecraft, via some kind of man-made radiation belt?

As a matter of fact, the answer could be yes, according to a team of researchers at the Rutherford Lab in UK.

Using the principle of the Van Allen belts, scientists could install modules on spacecraft which would generate a magnetic field around the body of the vehicle. This artificial magnetosphere of the spacecraft would trap incoming radiation, separate protons and electrons, causing a separation of charge in space, and thus deflect more incoming radiation!

Best of all, this would only need to be 100m-200m in diameter, unlike the real Van Allen Belts which stretch out for thousands of kilometers. This is still an experimental idea, but it may be key to giving our spacecraft materials some extra assistance in blocking radiation.

Final Thoughts

Ultimately it likely won’t come down to a “end all-be all” solution for space radiation, but rather a series of smart and innovative solutions that will allow us to enter deep space. Some say the GCR problem is what will forever keep us tied to our home planet, however the fact that viable solutions are already being developed, shows a more-than positive future for our transition into an interplanetary future!

In my next article, I’ll be shedding light on one creature’s specifically cool way of protecting their DNA from radiation damage, and how humans are using its unique evolutionary toolkit for next level genetic modification.

Stay tuned, thanks for reading. Feel free to check out the sources I used below to maybe think of some awesome ideas of your own!

Sources:

NASA Polyethylene Research: https://science.nasa.gov/science-news/science-at-nasa/2005/25aug_plasticspaceships

GCR Info: http://www.srl.caltech.edu/personnel/dick/cos_encyc.html

Magnetosphere Research: http://www.minimagnetosphere.rl.ac.uk/

Free Radical Damage: https://en.wikipedia.org/wiki/Health_threat_from_cosmic_rays | https://en.wikipedia.org/wiki/Free_radical_damage_to_DNA