Obstacles to Space Exploration Part V: Plastic, Poop, Pieces of Goop

Source darrscleaning.com

Waste disposal in space stinks. This week, we look at one way to get the stink out.

The International Space Station, the American, and the Russian space fleets dispose of garbage in similar ways. Russian and American manned orbital missions are pretty short, so their waste can be stored and disposed off after landing.

The astronauts on the ISS pack their waste into a Progress module and send it back towards Earth where it burns up upon reentry. (Thanks to Jeff for the clarification.)

On a completely unrelated note, the Progress module is also known as the world’s most financially inefficient garbage scow. Source ESA

There aren’t a whole lot of elegant solutions to the waste problem. That's why we just bring it home with us. But on a long-term flights, we don't really have that option.

We technically could send the garbage home, but it would be a huge waste of resources. First, we won’t have a whole bunch of spare Progress modules trailing behind our ship, second, any we do have will likely be reserved for emergency situations, and third, we're trying to save as much weight as we can at launch.

We could burn our garbage, but that would use up all the oxygen on the ship and render the point moot. At least for the astronauts still on the ship.

We could just take it with us and dump it wherever we land, but anyone who thinks this is a good idea has never met an angry planetary geologist. They tend to drink a lot and have poor tempers.

This person may or may not actually be an angry drunk exogeologist. I really have no idea. I found it here.

We could drop the garbage out of the ship but that would change the ship’s momentum. Dropping trash would only induce very small changes - see Newton’s Law - but if we screw up the calculations even a little, it could mean arriving at the target planet’s position three weeks before it gets there. Unless we have a lot of extra fuel, if there's no planet, we have no brakes.

The pic is horrible, but I still love you NASA.

So how do we get rid of our trash without following Pioneer out of the solar system, and without incurring the wrath of environmentalists and exogeologists?

Well, everyone knows what fertilizer is, and that most people are full of it. And as we talked about in the entries on food and air, hydroponic farms have been designed and tested for us in space. (Though I’m still not sure if research continues.)

Not only do hydroponic farms serve as air and food sources, they also serve as natural garbage bins. The minerals, bacteria, and other stuff in human waste can be used by our plants as fertilizer, which then filters our air, and grows us more food to make poop from. Plants also add a nice splash of colour to our spaceship.

Poop may be the biggest offender, but it’s not the only one. Urine, dirty air filters, filthy and ripped clothing, bandages, sanitary napkins/toilet paper, plastics from food wrappings, the list could go on forever. But there are simple, though not easy, solutions for all of them.

Our urine can be filtered using the same process as the Space Shuttle and ISS, and dumped right back into the drinking water. Or the water can be used by the plants, and partially filtered by the soil network, and we can use the ammonia and other chemicals in urine to keep our space ship’s windows clean.

Paper products can be sterilized and used in the farms. (There could be issues with disease transfer here with stuff like sanitary napkins. But without getting too graphic, blood is a great fertilizer.)

We do have a problem with plastics for perishable items. We can’t just kept the powdered milk in a big Tupperware bin.

Pic "borrowed" from this blog

Actually, we probably could. Look at the seal on those babies.

However, we can’t keep most perishable foods or medicines in Tupperware bins. They must be protected with strong plastics, and separately packed such that using one item doesn’t limit the shelf life of every other item.

Luckily it turns out we’ve had edible plastic for years. (source 2002)

The plastic probably won’t taste very good, so it won’t make a good snack. But because of the nutritional content the waste can be dumped in our farms, or stored in an indoor compost heap for later use. We’d have to worry about the gases generated by a compost heap, but an astronaut can always find a use for gases that burn.

So, just in regards to food packaging, paper, poop and urine, we cut out a large portion of our human-produced waste.

Unfortunately, we also have non-biodegradable wastes. Every time a tool breaks, and every time a motherboard gets fried (in the dangers section you will learn about why motherboards get fried), we end up with waste plastics, metals, and 166MHz CPUs.

The good news is that broken tools and heavy plastics can be kept. Not to throw away upon arrival to enrage the Earth Liberation Front, but to melt down and form into new tools upon arrival.

There are no hardware stores on Mars, and a re-supply mission following the most efficient path would take more than half a year to get from Earth. And that’s if a rocket is already sitting on the pad ready to go.

Stuff breaks, and we’ll need some way to reuse the material in the stuff that breaks. We don’t need to take a smith’s oven, but it ain’t a bad idea to have something that can melt everything down when we’re done with it. Melt it, pour it in a mold, wait for it to cool, and voila! New hammer.

Waste disposal is really one of those things that has no fancy solutions. Many people would say that the hydroponic farm is a fancy solution, and in a way they would be right. A full-scale hydroponics farm has never been tested on a long-term mission.

I may be a bit too optimistic, but I don't think we have to worry about that. Hydroponics is a pretty well-known science – half of my friends are experts – so it should be just a matter of time before we can make it work in space.

Waste removal has only three tenets: reduce, reuse, recycle. If we follow these rules, we'll be fine.

Wait.

Four tenets.

Don’t piss off exogeologists.

I'm really sorry for using your picture twice.