Populate the space station with microbes to stay healthy

Author: Jeanette Sams-Dodd & Frank Sams-Dodd

Founders/Directors of Willingsford Ltd

Microbes are generally associated with infection, and the usual response to their mere presence is to eradicate them as quickly as possible. For example, the “no-rinse soap” used during space travel mainly consist of antimicrobials, i.e. chemicals that kill microbes, with the aim to remove bacteria on the skin.
It is correct that microbes can cause disease, but it is microbes that created an environment and an atmosphere on Earth that allow plants and animals to exist. Microbes are literally everywhere, and we ourselves depend upon microbes to keep our external facing surfaces healthy and to help with the breakdown of food in our gut and production of substances that our body needs. The microbes form actual communities with thousands of species in and on us, for example the gut, respiratory and skin microbiomes, and these communities collaborate with our immune systems.

​To give an idea of their importance, data suggest that it is the pollution from antimicrobials that is the primary responsible for climate change because their impact is very broad and reduces the microbial diversity and changes the microbial balance. Similarly, studies indicate that antibiotics have long-term impact on our health, and they have been shown to increase the frequency of cancer, diabetes, asthma as well as functional impairments in children’s development, immune function, and cognition. Poor gut health, which usually means an unbalanced and low diversity microbiome, has also been associated with mental health problems including depression and anxiety as our gut microbiome is responsible for producing substances needed for normal brain function.
On the International Space Station skin issues and problems with wound healing have been reported. Microgravity and radiation have generally been assumed to be responsible for this and the fact, that “no-rinse-soap” is a cocktail of antimicrobials, has received practically no attention. Antimicrobials are traditionally used for treating wounds, but the US FDA reported in 2016 and again in 2022 that they are ineffective in treating wounds, and studies have demonstrated that antimicrobials directly impair healing and that a healthy wound microbiome is required for healing to take place. These novel conclusions banning antimicrobials in skin care and wound healing are further supported by the positive findings with a new technology, MPPT (micropore particle technology), which acts by regulating the wound microbiome without killing anything. MPPT has been able to achieve 100% wound closure rates, including in complicated wounds and in people with impaired immune function. This observation shows that approaches that support the collaboration between the microbes and the immune system can be much more effective than the traditional, old blanket-bombing approach of eradicating all microbes, which renders the skin debilitated and less resilient.

These observations are relevant to space travel, in terms of both the environment onboard and clothing, food and methods of ”washing”. Our bodies have evolved on Earth, where microbes were and are present, and our evolution has benefited from this as the microbes assist in protecting our surfaces and in delivering nutrients and critical compounds needed for our health. This dependence persists, even if we decide to leave Earth for shorter or longer periods of time. It is therefore a necessity, particularly for deep space travel, which does not permit us returning to Earth periodically to update our microbiome, to develop environments and procedures onboard that can sustain our microbial requirements.
These considerations are based on an article recently published in Frontiers in Public Health, which focuses on the role of antimicrobials in causing climate change from severely damaging the Earth’s microbiome. The impact of antimicrobials on the Earth microbiome and the microbiome inside a space station are comparable as they are both closed systems. It is consequently important to consider the essentiality of the microbial environment, when planning human life outside the Earth’s environment.

Sams-Dodd J. & Sams-Dodd F.: The contribution of antimicrobials and antimicrobial resistance to climate change and a possible way to reverse it whilst still offering high quality healthcare—a conceptual analysis. Front. Public Health, 15 July 2025, Sec. Infectious Diseases: Epidemiology and Prevention. Volume 13 - 2025 | https://doi.org/10.3389/fpubh.2025.1644086

Changes in the astronaut skin microbiome over time whilst living on a space station, i.e. a closed environment.
Top: bars show distribution of sensitive, resistant, and virulent microbial species, and blue line shows number of different species (diversity). Bottom: a theoretical excerpt of the skin microbiome. The absolute number of microbes remains unchanged across A, B and C. The ability of the skin to withstand external influences and to regenerate depends on a rich (diverse) well-balanced microbial environment.
A: The microbiome when leaving the Earth. Most microbes living naturally on the skin, i.e. commensals, are sensitive to antimicrobials and will be killed if exposed to antimicrobials. A few species are resistant to antimicrobials as indicated by the ring around them. Without exposure to antimicrobials, resistance and antimicrobial-associated virulence are not expressed and do not affect the diversity and balanced composition of the skin microbiome and skin health.
B: After using antimicrobial “no-rinse-soap” on the skin for a relatively short period of time. The antimicrobials have caused several sensitive species to disappear; some commensal species to develop resistance (blue ring); some species to develop resistance and virulence; and some of the already resistant species to turn virulent. Skin health is challenged and will typically show less resilience.
C: After using antimicrobial “no-rinse-soap” on the skin for a long period of time and living in a closed environment without the possibility of replenishing the microbiome. All antimicrobial-sensitive microbes have been eradicated and all remaining species are resistant. Many species have developed virulence. The virulent species increase their presence more efficiently and have therefore created further imbalance in the already species poor (low diversity) microbial community. Skin health is poor, typical symptoms will be redness, dryness, flaking, itches, rashes, blisters, tiny wounds etc.
Differently coloured dots represent different species of microbes. Outer dark-blue ring: resistant strain.  Outer dark-blue ring and spikes: resistant virulent strain.