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One of the long-term implications of global crises like the COVID-19 pandemic on outer space could be an intensification of the effort to explore new worlds for human habitation. It appears that outer space could be the only place to remain free from the pandemic threat that has been ravaging the world of late. Though microbes have been held responsible for a lot of human ailments, it is also a fact that human survival on earth will be impossible without their presence. Microbes are omnipresent on earth, and it is highly likely that the first living thing to ever reach outer space from earth would have been a microbe. The significance of these microbes for the outer space domain is well reflected in the fact that Astromicrobiology or Exomicrobiology has emerged as a scientific stream devoted to the study of microorganisms in space.


Microbes, just like on earth, can create problems for human activities in the orbit and beyond. It is certainly not possible to completely ensure that the human outposts in the orbit can remain free from the presence of microbes. The cargo and the crew, which are transported regularly to the International Space Station (ISS), for instance, certainly is not devoid of microorganisms. Efforts are made, therefore, to ensure that all payloads going to the ISS are sterilized so that they do not present a biological hazard to the astronauts. Even within the ISS, samples are routinely collected and sent back to the earth for analysis of the presence, diversity and growth of various microbes in the station. As a result of these studies, it has been confirmed that bacteria like Staphylococcus aureus, Staphylococcus epidermidis, Burkholderia, and Micrococcus luteus, as well as fungi like Aspergillus are present in the ISS. So far, around 250 types of such microbes have been identified in space. There is an added element of risk to humans during space travel due to microbial threat, because immunity is adversely affected by the microgravity conditions in space.


It is not just the humans who could face the threat from microbes in orbit; even equipment could get damaged in various ways due to the increased activity of microbes in the outer space environment, due to microbial growth and activity affecting material characteristics. For instance, there was an instance of a fire detector of the ISS breaking down as a result of bio-corrosion, as well as another instance of the visibility of the ISS window getting affected as a result of metabolic processes of fungal colonies. Various measures have been adopted to deal with such issues, including more effective decontamination processes, materials with anti-microbial properties or coatings as well as detection and diagnosis systems against microbial damage.


Beyond the earth’s orbit, there is the larger issue of contamination of foreign celestial bodies from terrestrial microbes as a result of various lander and rover missions. The presence of life beyond earth is one of the key areas of study in the area of deep space exploration. Contrary to popular culture, the probability of finding life outside the earth, especially inside the solar system, could be in the form of primitive microbes rather than advanced life forms. This is because, only such life forms can survive in extreme conditions outside rare habitable locations like the earth. Hence, the search is ongoing about the presence of water in natural satellites like the Moon, planets like Mars, and asteroids like Bennu. If various landing missions on other celestial bodies introduce microbes that originate from the earth, it could lead to the reporting of false positives in the investigations on life beyond earth. This will, therefore, fundamentally undermine the quest for extra-terrestrial life. There remains the possibility that contamination could have happened in the past, like the Apollo landings on the Moon. Space agencies are increasingly going the extra mile to ensure that such costly errors do not happen. For instance, the National Aeronautics and Space Administration (NASA), in 2017, destroyed its Cassini spacecraft orbiting Saturn at the end of its life so as to ensure that the spacecraft does not impact and contaminate any of the planet’s watery moons, Enceladus or Titan.


In addition to such “forward contamination”, there is also the possibility of “backward contamination” – of microbes from extra-terrestrial environments hitching a ride back to the earth in sample return missions. This can have unforeseen consequences for the earth, and can perhaps even lead to a pandemic considering the novel nature of such alien organisms. Such a scenario has been well explored in science fiction, but may not be restricted to it in the near future, with the concept of “planetary protection” gaining prominence in the wake of COVID-19. The concepts of forward and backward contamination were foreseen even before the Space Age, and were further codified in the Outer Space Treaty of 1967.


With the current and proposed sample return missions from nearby bodies like the Moon, Mars and the asteroids, and more importantly the future plans of sample return missions from distant bodies like Europa (Jupiter’s moon) harbouring more possibilities of life, there is a growing concern regarding interplanetary contamination. The emergence of ambitious private entities like SpaceX as well as the recent push towards space-based commercial activities such as mining has further added to the probability of such scenarios. Disinfection and quarantine procedures will remain central to taking precautions against contamination.


Though controlling the inadvertent propagation of microbes into the space is one part of the microbiology dimension in outer space, it has to be noted that such organisms are also deliberately introduced into the orbit for the purpose of scientific research. The ISS itself is an orbiting laboratory where various microbial studies are conducted. It has various facilities including a Bio Lab, a Bio Culture System, an Image Processing Unit, a Light Microscopy Module, and a Microgravity Science Glove Box, among others. There are various reasons why microbiology research has been carried out in orbit. Primarily, an understanding of the various microbes in the space environment could help in developing cures for diseases. The way mutations occur in these organisms provide the key to developing such solutions for not only the existing strains, but also far more potent ones which may arise in the future. With a growing number of population spending more time indoors, especially during COVID-19 induced quarantines and lockdowns, facilities like the ISS becomes important to study how these organisms propagate in enclosed spaces.


The outer space environment is significant here, because microgravity accentuates the capability of these organisms. Moreover, the lack of a natural environment with hardly any competition or threat allow them to further thrive. For instance, it has been proven that the same strain of the Salmonella bacteria grown in outer space is much more lethal than its terrestrial version. The culture of these microbes in outer space can lead to their enhanced growth, antibiotic resistance and radiation resistance. Microbial research in outer space has established that more antibiotics can be produced in space than on earth, even double the amount in certain cases. It can also lead to scientific findings that may enhance human capabilities. For instance, it has been found that a specific protein called Dsup, which is found in Tardigardes, has the ability to repair radiation-damaged cells of not only the microorganism, but also that of humans. Hence, this finding could help in sustaining the health of human crew during long duration, inter-planetary scale spaceflights.


There is more to the study of microbes in space than its impact on human health. Scientists have identified that microbes may play a huge role in future plans of making other planets habitable. Microbes like Rhizobium, which play a key role in converting atmospheric nitrogen to nutrients for plants, and in turn maintain the gaseous equation in the atmosphere, will be extremely important in such instances. Microbes can also be used to start a food chain to sustain a habitable planet, as life on earth itself evolved from these organisms. Moreover, microbes help in breaking down sewage and toxic waste, facilitating the development of sustainable environments. As more and more concerns build up in the coming months and years about pandemic-causing viruses and drug-resistant bacteria, there will be a growing emphasis on utilizing the potential of outer space for advancing the cause of human health. Outer space could hold the key to developing solutions for pandemics like COVID-19.


Hence, outer space activities raise immense opportunities as well as serious challenges with regard to dealing with microbes. A country with an ambitious and rapidly expanding space programme like India will have to pay increasing attention to astromicrobiology as it ventures into interplanetary missions with lander and sample return components, as well as manned spaceflight with space station ambitions. India will have to adopt best practices from more experienced nations as well as create its own standards to ensure that human health and space environment are not compromised by spacefaring activities. At the same time, it should increasingly focus on cultivating its own expertise in space-based microbial research so as to develop innovative solutions for human health at the national and global levels.


Disclaimer: The views expressed in the article are personal.