Asteroid crew members aboard the International Space Station (ISS) consider clean conditions to be their highest organizational priority. The ISS’s highly sterile setting might create health risks that endanger crew members. Researchers have found that the ISS contains inadequate microbial diversity, which needs assessment regarding proper space habitat design because of its impact on immune system functionality. Could being too clean in space be a problem?
The International Space Station has operated as a strictly sterile facility since its establishment through routine surface maintenance performed by space station astronauts. A new research article in Cell demonstrates that intensive surface sterilization on the International Space Station produces unexpected adverse outcomes. The absence of various microbes from the International Space Station creates health challenges for astronauts because their immune systems become compromised, leading them to suffer from skin rashes and other immune-related symptoms such as cold sores. According to the research team from the University of California, San Diego (UCSD) under microbiologist Rob Knight, future space habitats must develop deliberate microbial cultivation plans to enhance human wellness. According to Knight’s report to Space.com, he stated that “Sterile environments are not, in fact, the safest environments. The natural exposure to beneficial environmental microbes is vital for sustaining health since humans have co-evolved with such microbes since the start of time.”
A Lack of Microbial Diversity
The research team collaborated with astronauts to obtain 803 swabbed surfaces across the ISS kitchen, bathroom, and common areas. The analysis team used surface swabs from the ISS to evaluate how they matched up with microbial samples obtained from Earth-based buildings, including regular homes, offices, and hospitals. The results revealed a striking lack of microbial diversity on the ISS. Most of the bacteria found on the station came from human skin, with very little representation of microbes typically found in soil or water on Earth. This made the ISS microbiome resemble highly industrialized environments or spaces isolated from nature, such as quarantine dormitories used during the COVID-19 pandemic. “The ‘home’ on Earth that looks most similar to the [ISS] was an isolation dormitory used during COVID-19,” said Haoqi Nina Zhao, an environmental chemist at UCSD and co-lead author of the study, in an interview with Scientific American. Because human exposure to diverse microbes helps regulate immune function, it is problematic to observe limited microbial variety. Humans have learned to coexist with countless microorganisms throughout thousands of years, so various microorganisms play important roles in maintaining wellness. Lack of regular contact with favorable microbial species could result in astronauts developing immune-related illnesses along with various health complications.
Living in an Artificially Sterile Space
One of the study’s key findings was that the ISS microbiome consisted almost entirely of bacteria associated with humans. While that might seem preferable to having unknown environmental bacteria, it also means that astronauts are essentially living in a bubble of microbial waste. “There’s a big difference between exposure to healthy soil from gardening versus stewing in our filth,” Knight explained to The Guardian. “If we’re in a strictly enclosed environment with no ongoing input of healthy microbes from the outside, it could have negative effects on health.” Compounding this problem is the frequent use of chemical disinfectants. Studies detected high cleaning product residues at different locations in the station despite astronaut cleaning restrictions of four days before sample collection. The excessive application of disinfectants in spaces prevents harmful bacteria transmission but wipes away beneficial microbes from the environment.
Potential Health Impacts
Scientists are not yet certain how much the lack of microbial diversity is affecting astronauts’ health, but previous research suggests a connection between low microbial exposure and immune-related issues. “[A lack of] microbial diversity in other environments, such as homes, has been associated with health problems parallel to those seen in astronauts,” Knight told the Australian Broadcasting Corporation. On Earth, studies have shown that people who grow up in highly sanitized environments are more likely to develop allergies, autoimmune diseases, and other immune dysfunctions. The same principle may apply in space. The unique hazards of space travel require strong immune function for astronauts to maintain their health in conditions of microgravity, exposure to radiation, and physiological stress.
Rethinking Hygiene in Space
The study results create a crucial query about managing microbial diversity within future space dwellings while blocking dangerous pathogens. Scientists suggest several potential solutions. A solution may include the addition of probiotics within space station environments through both probiotic cleaning products and surface cultivation of helpful bacteria. Probiotic-based cleaners differ from traditional disinfectants because they use non-harmful bacteria that dominate over dangerous microorganisms. The exposure of astronauts to nutritious bacteria through their dietary choices presents another viable solution. By increasing fermented food consumption, including yogurt along with kimchi and kefir, people may restore their gut microbiome since it plays an essential role in supporting immune health. The introduction of plants along with small animals to space habitats remains a planned approach for boosting microbial diversity inside these habitats. The implementation of this strategy needs thorough experimental assessments to protect against any accidents involving dangerous microbes. Biologist Odette Laneuville of the University of Ottawa expressed to The Guardian “I don’t want parasites and fungi up there” when discussing the topic.
Implications for Future Space Missions
Human missions outside Earth require profound knowledge and control of microbial environments to ensure their success. The future space stations and lunar bases must establish self-sustainability because they will not receive the same continuous supply support from Earth as the ISS. There will be no alternative for maintaining astronaut health in these environments if we do not establish a proper microbial balance. Scientist Rodolfo Salido of UCSD told The Guardian that future human-built space facilities including space stations should promote diverse microbial communities to recreate natural terrestrial microbial exposures instead of using high-level sanitation practices. Research must identify which microorganisms present no risk when introduced to space environments. Bacteria and fungi existing on Earth show potential changes in space because their behavior may shift due to microgravity along with radiation exposure and other space-specific conditions. Future scientific research will need to establish optimal methods for keeping a balanced microbiome healthy in a space environment.
Finding the Right Balance
Research demonstrates our requirement to change how we manage hygiene practices in space exploration. The ongoing need to maintain clean surfaces for infection prevention requires evaluation regarding possible unwanted health effects from overdoing surface sterilization. Asteroid missions need to strike the correct timing between pathogens removal and immune system protection by allowing beneficial microbial exposure.
Space agencies should plan for new approaches to design and maintain space habitats when they organize future missions outside Earth. Developing microbial diversity within space facilities will enable astronauts to maintain their health during space exploration journeys.
