Keeping space underwear clean

How to keep space underwear clean?

The BACTeRMA project, funded by the European Space Agency, is a two-year
follow-up project to the recently completed PExTex Project. After testing several potential future lunar space suit textile candidates on their suitability to serve as potential materials for a future lunar EVA (Extravehicular Activities) space suit, the BACTeRMA project aims to identify (novel) techniques that help to reduce microbial growth on the textile’s surface that may pose significant risks

Over 50 years after the first human set foot on the lunar surface, international space agencies plan the return missions to the Moon, but this time to stay. Opening the nextchapter in space exploration. With the vision of crews working at the future lunar laboratories, scientists address challenges that may arise in these permanentinfrastructures on the lunar or Mars surface.

Microbial growth on textiles not only plays a major role during the exploration of our Moon, but also for future long duration-flights to Mars. Astronauts’ dirty garments may turn out to be a challenge on those missions. Here, on Earth while laundry is a daily basis easy-doing, using washer and dryer would definitely not be practical in any space
habitat. Additionally, by establishing permanent infrastructures on the Moon, space agencies plan to store instruments and materials permanently on these extraterrestrial outposts, requiring future lunar EVA suits to stay and be used by different astronauts over an extended period of time. Storing space suits (in potentially favorable conditions
for microorganisms) again increases the risk of microbial growth. Either on an interplanetary ship or in a store on a planetary body: traditional wash and dry machines would be impractical in space, and also space suits cannot be washed consistently, hence, the solutions to avoid microbial growth are of particular importance

3D illustration of bacteria (c) Unsplash
3D illustration of bacteria (c) Unsplash

Microorganisms are everywhere

The human’s skin is inhabited by literally billions of microorganisms. If they remain on our skin, they are mainly harmless, most of them are even supporting our health. But if they start to colonize on the astronaut’s space suit, those microorganisms may turn into a challenge when different people use the same suits, or when suits worn for longduration flights, there can be risks involved, which are caused by microbial growth. Such risks include foul odors, health hazards (e.g., skin irritation, foot and skin fungus, Herpes Simplex), and functional risks to materials, including spaceflight textiles and other surfaces (Alekhova et al., 2004; Rhodes et al., 2011). No one likes to wear used socks of someone else. However, astronauts may use the space suit after another astronaut worn the suit during an EVA (an activity that is comparable to doing sports). This example shows how important to implement clean solutions against microbial “attacks” on textile surfaces. Because microbial growth primarily affects the inner space suit layers (the layers are in contact with the human’s skin), the BACTeRMAproject focuses on the inner space suit layers (like underwear/ under garments).

Microscopic view of textiles (c) ZEISS Microscopy
Microscopic view of textiles (c) ZEISS Microscopy

The BACTeRMA project studies biocidal textile processing techniques based on bacterial metabolites. Bacterial metabolites are intermediates, and products that occur during bacterial metabolism. For example, β-carotin is a well-known intermediate that appears in carrots and other yellow-reddish and dark green vegetables. It is formed during the synthesis of vitamin-A and is mainly used as a food additive to color food yellow. Next to their usage as a natural color, other bacterial metabolites are known for their antimicrobial effects. For instance, antimicrobial peptides (short chains of 2-50 amino acids linked by peptide bonds) are produced by microorganisms and represent a structurally diverse group of antibiotics. In other words, the aim is to keep the dirt away from the astronauts’ garment by treating its textile with antimicrobial agents.

Tasked by the European Space Agency, the Austrian Space Forum, in partnership with the Vienna Textile Lab, the research consortium explores the biocidal potential of the secondary metabolites of bacteria. The team aims to identify various factors that help to reduce or terminate the microbial strain on textiles. Furthermore,microbial dying strategies (based on bacterial metabolites) will be tested for their potential to serve as antimicrobial substances. The idea is to develop a method that works like techniques already used, e.g., to impregnate high-tech textiles, such as the outdoor winter jackets which are often coated with polyurethane (PU) to render them waterproof.

Using traditional silver/copper coatings against microbial growth does not fulfill all requirements essential to apply to spaceflight textiles. The main reason for this is that silver/copper coatings have shown to pose a risk to humans’ health and the environment.

Dying techniques that are based on microbial metabolites already demonstrate their potential to reduce microbial growth in terrestrial settings. However, none of these novel techniques have been tested for their suitability for space-applications.
Therefore, this project aims to find appropriate solutions for the space industry, particularly in inner layers of astronauts’ EVA suits for future lunar (and later Mars) exploration.

Further Informationen:

Alekhova, T. A., Aleksandrova, A. A., Novozhilova, T.Y., Lysak, L. V., Zagustina, N. A. and Bezborodov, A. M. (2004) ‘Monitoring of Microbial Degraders in Manned Space Stations’.
Rhodes, R., Orndoff, E., Korona, F., Adam, Proitz, D., Smith, M. and Wong, W., eds. (2011) Biocontamination Control for Space Suit Garments: A Preliminary Study

This article is available in: German