NASA researchers are testing tiles made out of garbage — including plastic water bottles, clothing scraps, duct tape and foil drink pouches — in an attempt to turn astronauts' trash into a space mission’s treasure.

Like their earthbound counterparts, astronauts generate junk in their day-to-day lives, but unlike us, they can’t just bag it and leave it on the curb.

"We don't want to contaminate the surface of an asteroid or something just by throwing the trash out the door," said Richard Strayer, a microbiologist working on the project.

"If NASA doesn't do something about it, then the spacecraft will become like a landfill, with the astronauts adding trash to it every day."

High-tech trash compacting

The discs aren’t made in just any old trash compactor. The device, which was engineered at the agency’s Ames Research Centre in California, heats the garbage for more than three hours at temperatures between 148 C and 176 C.

A pound of material can be compressed into one tile, which makes the trash about 10 times smaller.

To make use of the material, researchers at NASA's Kennedy Space Center in Florida are running tests on circular tiles made out of compressed trash. The discs, which went through a specialized compactor that melts but does not burn the waste, were created using a recipe based on trash from shuttle missions.

Each tile is just over a centimeter thick, roughly 20 cm in diameter — which is a bit larger than a standard compact disk — and made from about a day’s worth of junk.

But before researchers can send the discs on a deep space mission, they must answer several questions: Can they be safely stored on a spacecraft?  Can they be sterilized so they are free of microorganisms? Can water be removed from the trash and re-used?

DIY radiation shields

Mary Hummerick, another microbiologist working on the project, sees potential in all the plastic packaging the astronauts discard.

If the plastic content of the disks is high enough, "they could actually shield radiation," she said. NASA’s website explains that the tiles could be arranged to shield the astronaut’s sleeping area or reinforce the spacecraft’s "storm shelter."

If all goes as planned, the end product could be especially important for crews living in space for up to two years — which is, NASA points out, the expected duration of a Mars mission.

"If the time and temperature tests seem to be achieving what we want, we'll go to long-range storage testing," said Hummerick. 

"The mindset is, with limited resources, whatever you can use, you want to be able to repurpose that."