Using Trash To Protect Astronauts | Out Of This World Weekly

Every year on the International Space Station, tons of trash are sent back to Earth in cargo capsules which burn up upon re-entry into Earth’s atmosphere.  Nobody really knows what else to do with all that garbage.  There isn’t enough room on the inside of the station to store it and they can’t just jettison it into orbit, where it could become dangerous to other spacecraft due to the high velocity.  It is one thing getting hit by a plastic water bottle being thrown at you and something entirely different when it is traveling at 17,000 mph.  Since most of the supplies are sent up in lightweight plastic wrapping which is also ideal as radiation shielding, researchers are evaluating how well recycled trash can protect astronauts from radiation danger.  To do so, they are compacting and heating the trash so that it melts, yet isn’t incinerated, into small tiles.  Theoretically, these tiles could line the outside or inside of a spacecraft at key locations as to provide better radiation shielding.  

While radiation is a danger to astronauts in Low Earth Orbit, the radiation that is encountered in interplanetary space can be worse.  Without any magnetic protection from Earth, radiation ejected from the sun in solar storms can be extremely dangerous, even deadly.  You would think that the aluminum skin of spacecraft would do a good job of protecting astronauts from radiation, yet it doesn’t do very well at all and can actually increase radiation if you are too close to it. Engineers have found that materials that have high amounts of Hydrogen tend to serve well as radiation shields.  Using water as radiation shielding has been considered, since it will be needed anyways.  Only recently has the same plastic that we come in contact daily has been considered as radiation shielding.  Since plastic is made from Hydrocarbons, which are made up of a large amount of Hydrogen, it turns out that it also serves as a radiation shield.  While a single plastic water bottle isn’t going to save you from a sunburn on a sunny day, a hundred plastic water bottles might, especially if they are compacted to 10 times their original size. 

Compacting plastic trash into small tiles also solves another problem.  Anyone who ever used a trash compactor on Earth knows that with a compactor, you don’t have to take out the trash as often.  This would be very handy on trips to other planets like Mars, which could take months or years to get back to Earth.  Currently, we aren’t allowed to just throw trash out an airlock even when we are in interplanetary space.  We don’t want the same germs that inhabit the inside of a water bottle to spread to Mars, asteroids, or anything else that might be floating around in our solar system.  It might severely hamper our efforts to detect native life on Mars if we erroneously detected life from Scotty’s snickers bar that he dropped while on Mars.  It has been shown that some life can survive the harsh reality of space, only to come back to life when exposed to favorable conditions.  It turns out that one way to sterilize plastic is to cook it at 350 degrees for 3 1/2 hours, which is exactly what it takes to melt down plastic into neat little tiles. 

Everything that we send up into space costs large amounts of money just to get it there.  To send 16oz of water into space costs about $10,000 and the weight of the plastic bottle that carries it could cost anywhere from $300 to $400.  Of course, they don’t use little plastic water bottles in space because of this exact reason but there are a large amount of little plastic bags that are used to store food.  Even so, when a cargo module (shown of left) falls back to Earth it can hold from 2,200 to 3,700 pounds of trash in it.  A significant portion of this garbage could be used as a radiation shield for the astronauts without having to pay to launch a shield.  Remember that a 1,000 lb shield would cost $10,000,000 to launch into orbit.  This type of recycling of material would even be more useful on long term missions to asteroids or Mars.  Radiation damage to humans in space poses a high risk and large amounts of garbage poses operational risks.  In the use of garbage as radiation shielding we can increase the safety and comfort of the astronauts while sterilizing, using, and getting their garbage out of their living space.

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