Space is at a premium on the International Space Station (ISS), but astronauts have to find room to temporarily store over two tons of trash at a time until a resupply ship can take it away.
A four-person crew will produce thousands of pounds of waste in a year-long mission, including empty food packets, used hygiene items, and discarded clothing.
ISS crew members have to sort and compact this waste, squeezing it into special garbage bags that are then stowed away. This method of waste storage and removal could have health implications for those onboard the ISS and would pose an even greater challenge on longer missions that reach further into space, where scheduled visits from resupply vehicles are not an option.
In an environment where every resource is precious, NASA has been searching for recycling solutions that reduce the footprint of the trash astronauts produce and put the byproducts to good use. A new NASA competition, launched in September 2024, is offering a $3 million prize for innovations in recycling waste on deep space missions.
Various technologies are already being put through rigorous testing. For example, the “Heat Melt Compactor” reduces waste into 9-inch square tiles. These tiles take up less than an eighth of the original volume and could be utilized on the spacecraft as part of a radiation shield. The water that boils off during the process can be cleaned and reused, and the resulting gases can be safely vented off into space. Building on this technology, the Orbital Syngas Commodity Augmentation Reactor project (OSCAR, for short) is exploring how trash and even human waste can be recycled into a potentially useful blend of methane, hydrogen, and carbon dioxide.
The pressing problem of trash in space:
- The renewed ambitions to send humans back to the Moon and to launch manned missions to Mars make solving the trash issue a priority. While the ISS orbits the Earth at a relatively low altitude of 250 miles, making trash removal on resupply ships viable, the Moon is about 240,000 miles away, while Mars is roughly 140 million miles away.
- There are approximately 22,000 pieces of “space junk” (classified as debris measuring over 4 inches in width), plus thousands more that are too small to be tracked, zooming around our planet at speeds of up to 18,000 mph. Comprised of materials including old rocket bodies and non-functional satellites, this debris is a growing threat to future space missions.
- It’s an ongoing challenge to ensure that the new waste management technologies will work in zero gravity without undertaking hugely costly trips to space. The OSCAR technology has so far been tested for about 2 seconds in microgravity at the NASA Glenn Research Center’s drop tower, and then for around 5 seconds at their Zero Gravity Research Facility.
