Compaction and drying in a low-volume, deployable commode

Eric Litwiller*, John Hogan, Travis Liggett, John Fisher, Ric Alba

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Scopus citations


We present a device for collecting and storing feces in microgravity that is user-friendly yet suitable for spacecraft in which cabin volume and mass are constrained. On Apollo missions, the commode function was served using disposable plastic bags, which proved time-consuming and caused odor problems. On Skylab, the space shuttle, and the International Space Station, toilets have used airflow beneath a seat to control odors and collect feces. We propose to incorporate airflow into a system of self-compacting, self-drying collection and stowage bags, providing the benefits of previous commodes while minimizing mass and volume. Each collection bag consists of an inner layer of hydrophobic membrane that is permeable to air but not liquid or solid waste, an outer layer of impermeable plastic, and a collapsible spacer separating the inner and outer layers. Filled bags are connected to space vacuum, compacting and drying their contents. Candidate materials and components are evaluated to determine permeability, strength, and ease of use. Bags attach to a deployable seat and vacuum blower. The operating procedure is described and system mass, power, and volume estimates are presented.

Original languageEnglish (US)
Title of host publication37th International Conference on Environmental Systems, ICES 2007
StatePublished - 2007
Externally publishedYes
Event37th International Conference on Environmental Systems, ICES 2007 - Chicago, IL, United States
Duration: Jul 9 2007Jul 12 2007


Other37th International Conference on Environmental Systems, ICES 2007
Country/TerritoryUnited States
CityChicago, IL

ASJC Scopus subject areas

  • Automotive Engineering
  • Safety, Risk, Reliability and Quality
  • Pollution
  • Industrial and Manufacturing Engineering


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