Look Up
Our researchers looked into the potential use of innovative cleansers and water-based anti-microbial agents being considered to solve dry skin conditions and microbe control on astronauts who were living on the International Space Station (ISS) for months at a time.
On the the International Space station alcohol sanitizers and other products are prohibited, because the vapors interfere with the air-revitalization system. Only non-alcohol disinfectants can be used. Personal hygiene of astronauts is maintained with frequent sponge-baths and only occasional soap & water showers. Also, evaporative cooling of the skin is unusual in microgravity, since sweat does not drip off the skin as on Earth, so as it builds up a layer it actually insulates and traps heat, reducing cooling of the skin. Humidity control in the ISS is difficult to maintain and often water vapors condense on the walls and behind equipment which permits the growth of certain molds and bacteria where decontamination is often impossible. Also it has been shown that certain bacteria become more infectious and resistant to antibiotics in microgravity. This produces special requirements for cleaning crewmember’s skin, while maintaining proper moisture content and natural oil content. Typical oil-based emulsions can sometimes help moisturize, but they usually leaves greasy residues that can be transferred to keyboards, display screens, etc. creating additional surface cleaning problems for the crew.
Other practical considerations include containers, dispensing and trash production. Small disposable containers of soap, liquids or gels present more trash that has to be transported back to Earth, hence it is preferable to use larger multi-use containers of cleaners and skin conditioners. Because microbes and spores are floating around in the space cabin atmosphere (they do not fall down to the floor as on Earth) the possibility of microbial contamination into the multi-use container is increased, hence, there is a special need for biocompatible, anti-microbial preservatives in skin preparations. Many preservatives, such as parabens, are now being abandoned from cosmetic products, so the selection of the preservatives is critical to prevent microbial growth inside the multi-use container. Dispensing only the correct amount of the cleanser or moisturizer is important, especially in a space cabin where tiny globules float along the air currents and can adhere to almost any surface.
