Space Technology: Exploring Trash Compaction and Processing


Maintaining a clean home and taking out your trash is an important chore in everyone’s weekly routine. Performing this same task in space comes with a whole host of additional challenges. Simply jettisoning the trash overboard wastes valuable consumables (water & gas) and could contaminate planetary bodies. Storing trash onboard a vehicle or habitat can create biohazards, smell, and occupy volume needed for other purposes. Whether we’re talking about International Space Station waste disposal or recycling on a future trip to Mars, space trash management is essential.

Four astronauts on the ISS can create over 9.75 cubic meters of trash per year – which is comparable to filling over 47 shopping carts. Handling that garbage has been an ongoing struggle onboard the ISS and will only become more challenging with longer missions into deep space.

However, this trash is difficult to process and dispose of for several reasons. Wet trash can grow mold, create hazards, and trap water that could otherwise be recycled and reused. Composition of the trash can vary and the system must remain hygienic and usable throughout its lifetime. In addition, processing of the waste can generate contaminants that must be cleaned. As an example, something as simple as leftover vinegar from a salad dressing might generate acidic gases that need to be cleaned to maintain a safe environment.

To solve these issues, Sierra Space began designing and building a Trash Compaction and Processing System (TCPS) for microgravity environments. The goal is to develop a system for NASA that manages crew-generated trash in support of long-duration space missions. The system will compact the trash, recover water, clean resulting gases, and form an easy-to-store square stackable tile to facilitate waste management in the next generation of space vehicles and habitats.

The system has been optimized to provide efficient waste sanitation, stabilization, and resource recovery while also reducing waste mass, power, and physical footprint.

The system is operated by loading waste into the compaction chamber where it is heated and compressed. Temperature and pressure sanitize the waste, then consolidate it into a stable tile while moisture and gas are evacuated for processing. This allows the trash to be safely processed and resulting gas and liquid recycled into the station systems.

A wide range of crew- or facility-produced waste can be handled including:

  • Packaging waste
  • Food leftovers
  • Used food and drink containers
  • Equipment and hardware
  • Maintenance waste
  • General trash

TCPS dramatically increases the water recycling rate and compacts trash into manageable, stackable, and compressed square tiles. These tiles are extremely dense, meaning they are compact and easy to store during long-duration missions. Tiles are also useful to provide supplementary protection from damaging radiation. In early testing, the TCPS demonstrated a water recovery rate of over 98%. Additionally, it reduced trash volume by over 75%, contributing to significantly lower waste management needs.


Minimal Crew Involvement

Ultimately, this waste management system is designed to facilitate a safe, efficient, and sanitary environment for the ISS crew or future habitats. It operates with minimal crew involvement, only requiring trash loading, the removal of processed tiles, and occasional cleaning and filter replacement.

Additionally, TCPS supports remote monitoring and control from Mission Control. This means that most operations can be managed without the help of an onboard crew member and ground engineers can monitor system health and performance in real-time.

Sierra Space specifically implemented system designs that were similar to that of many other appliances – including dishwashers and washing machines. A simple display informs crew of the system status and provides information & basic controls. The goal is to create a waste management tool that is intuitive, easy to use, and convenient for future crews as a standard appliance.

Some occasional maintenance is necessary, but TCPS is built with modular functionality for simple cleaning or replacement of parts. Prior testing demonstrated high reliability lifetimes even with worst-case trash loading, such as when contaminated, dirty, or oily waste is processed.

Data evaluated by the ground console will be used to monitor the system’s performance and make recommendations if any off-nominal maintenance is required. Otherwise, most of the system’s components, including the gas processing hardware, are sized for the lifetime of TCPS.


When Will the TCPS Be Tested?

The TCPS will be deployed to the International Space Station during the 2025 timeframe for initial checkout & performance testing. This will take place as a part of Sierra Space’s NextSTEP-2 contract in partnership with NASA Ames Research Center and Johnson Space Center.

This initial testing will assess:

  • Performance of water & gas recovery using real astronaut trash
  • Water & gas sample testing and analysis
  • The system’s long-duration reliability
  • Crew preferences and responses

These findings will help Sierra Space optimize the technology for incorporation in future deep space missions. They will also influence the mission architecture for future water recycling and trash management on the ISS. Following initial testing, TCPS will be used to manage ISS trash as part of the crew’s daily activities.

Space trash management, recycling, and disposal has been a long-standing issue, marking a serious complication in the future of deep space exploration. Through innovation and careful design, scientists & engineers are meeting the problem head-on with a system that will alter the future of astronautics.

Sierra Space researchers are at the forefront of revolutionary space exploration. From trash management to Vortex engine integration, we are disrupting interstellar transportation and transforming the Orbital Age®. The space race of tomorrow has begun, and private space companies are leading the charge toward safer, more accessible space travel.

Read more about our innovative space applications and our overarching mission.

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