The Challenge of Cleanliness in Deep Space

As space agencies plan for extended missions to the Moon and Mars, maintaining a hygienic environment has become a critical engineering hurdle. While much of the focus is on propulsion and habitat construction, managing sanitation is equally vital. Currently, astronauts on the International Space Station (ISS) wear clothing until it becomes unusable, at which point it is discarded. Because water is a precious resource in orbit, traditional laundry is not feasible.

However, long-term habitation on other worlds will require a different approach. Furniture and textiles—essential for psychological well-being during months-long journeys—can quickly become reservoirs for bacteria. In microgravity, these microbes can adapt, potentially posing health risks to crew members or causing damage to critical spacecraft hardware through corrosion.


Innovative Plasma Technology

A recent experiment led by Gabe Xu, a professor at the University of Alabama, suggests that water-free cleaning could be achieved using cold plasma. Unlike traditional chemical disinfectants like Lysol, which present air quality risks in confined, recycled-air environments, plasma offers a safer alternative.

In a controlled lab setting, researchers worked with NASA planetary protection engineer Chelsi Cassilly to test the effectiveness of this ionized gas. They applied a concentrated, pencil-thin jet of purple plasma to cotton fabric samples contaminated with Staphylococcus caprae, a bacterium commonly found on the ISS.


Effectiveness and Future Integration

The results were promising, indicating that plasma is more effective at neutralizing bacteria than the current ISS standards, which rely on dry vacuuming and chemical wipes. According to Xu, the process works by creating highly reactive oxygen and nitrogen species that penetrate fabric fibers, damaging the cell membranes of bacteria through oxidative stress.

«It is not going to remove the coffee stains from anyone's T-shirt, but it will remove the stuff that will make you sick.» — Gabe Xu, University of Alabama.

Key advantages of this technology include:

  • Water Conservation: The system requires only electricity and a gas source, eliminating the need for water-heavy cleaning cycles.
  • Fabric Safety: Testing showed no significant degradation of fabric fibers, even after five minutes of treatment.
  • Portability: Researchers are working toward developing a handheld device that would allow astronauts to easily sanitize surfaces and fabrics as part of their routine maintenance.

The research team, which recently presented their preliminary findings at the Astrobiology Science Conference, is now expanding their testing to include a wider variety of microbial species to ensure the technology is robust enough for the unique conditions of space habitats.