EXPLORATION
LIFE SUPPORT

WASTE MANAGEMENT OVERVIEW

The Waste Management System (WMS) develops innovative solid waste management technologies and procedures to enable future missions. Past and current vehicles have employed little or no waste processing, and have relied mainly on manual compaction of trash and subsequent on-board storage. Wet and dry trash is typically stored separately to minimize the potential for unwanted microbial growth and odor production. Trash storage on Shuttle is provided by dedicated and ventable lockers, while ISS trash is bagged and attached to habitation walls for temporary storage. Human wastes are collected in a commode (mechanically compacted on Shuttle only) and stored. Disposal of trash and human wastes on Shuttle and ISS is achieved by return to Earth in Shuttle or by incineration in the Earth’s atmosphere via the Progress Vehicle.

For future missions of short duration and/or small vehicle size, such as CEV and Lunar Sortie, WMS technology development is focused on reducing waste volume, waste safening and stabilization, and odor control. Reducing waste volume saves on spacecraft volume required for storage and can be accomplished via mechanical compaction methods. Safening and stabilization protects the crew and hardware systems through processes such as containment and drying. Controlling waste odors at the source reduces crew exposure and the contaminant loading on the cabin air trace contaminant control system (TCCS).

For longer duration missions such as Lunar Outpost and beyond, additional WMS capabilities are necessary to decrease costs and increase safety and self-sustainability. For example, advanced waste processing techniques such as mineralization can maximize volume reduction and water recovery, produce highly stabilized products for lengthy storage periods and support planetary protection regulations. Advanced processing may also be used to generate fuels and recover valuable resources including gases, water from brines, clothing (laundry systems), and other materials.

Tasks

Development of technology is underway or planned for each of the capability needs for waste management. These needs include:

1. Volume reduction- mechanical compactor, plastic heat-melt compactor
2. Stabilization- safening of feces & biological materials susceptible to microbial growth
3. Drying- freeze drying, vacuum drying, air drying, microwave heated drying
4. Water Recovery- freeze drying, air drying, microwave heated drying
5. Safening- odor removal and control, mineralization technologies
6. Resource recovery - incineration, hydrothermal oxidation, pyrolysis, composting
7. Storage- long-life containers
8. Disposal- waste container jettisoning

Crew Exploration Vehicle and Lunar Sortie - These missions require the capability for volume reduction, safening, stabilizing and short-term storage of wastes. The technologies under development to meet these needs include mechanical compaction, safe waste collection/containment techniques, and waste stabilization using cost effective drying methods. Different storage system configurations that significantly reduce waste storage volume are also being investigated. In addition, waste transfer between vehicles and the jettison of waste products while in transit are under consideration as a means to decrease propulsion costs.

Lunar Outpost - All of the WMS technologies identified for CEV and Lunar Sortie missions are potential candidates for supporting the Lunar Outpost. In addition, because of the extended mission duration, further development of advanced processing technologies is warranted. A major research area includes trash and human waste mineralization through technologies such as pyrolysis and incineration. Resource recovery techniques focused on clothes laundering and increasing water recovery will also be important measures towards overall cost reduction.