What We Study
There are two main types of microbial research projects supported by the NASA Space Biology Program. One type involves transporting specific microbes up into the spaceflight environment and characterizing how these specimens respond to its unfamiliar conditions. The other involves the cataloging, collection, and analysis of microbes already present on spacecraft such as the ISS, which have accumulated throughout the lifetime of the vessel. The former type of research project allows us to answer specific questions regarding the effect of spaceflight on microbial fitness and pathogenicity, while the latter allows us to collect data on an ongoing basis and develop a picture of how microbial populations evolve and change in space over time.
Discovering How the Spaceflight Environment Effects Specific Microorganisms
Past microbial studies have demonstrated that exposure to spaceflight results in some microorganisms becoming more pathogenic and resistant to antibiotics compared to their ground-grown counterparts. Other studies have shown that spaceflight changes the way some microbes colonize surfaces. Certain microbes are able to form biofilms on surfaces they adhere to, which are often organized in layers and have their own unique structures and architecture. These properties of biofilms ultimately help ensure the survival of the microorganism in a hostile environment by allowing it to form a barrier of protection (often comprised of dead microbes) against the outside world. Some biofilms may even contain multiple microbial species that work together in a symbiotic relationship. Space Biology-funded research has revealed that microbial biofilms formed in the spaceflight environment have architectures that are different from those observed on earth.
With each passing year, scientists are developing better molecular tools that help us characterize microbial growth and physiology, as well as molecular changes inside cells. Previously, the only way we could catalog microbes in the environment such as the ISS was by collecting samples, and culturing the microorganisms present in a laboratory on Earth. The method while effective, has its limitations: 1) not all microbes within these samples are culturable so their presence would not be detected using this method; and 2) not all microbes may survive the storage conditions required to transport these samples back to Earth, further reducing the output of this methodology. Thanks to advances in molecular technology, and to hardware platforms like Wetlab-2 and other instruments aboard this ISS, however, research scientists can now use molecular methods that identify microbial species by their DNA/RNA sequences to catalog microbial populations on built environment such as the ISS, without the need for culturing the samples back on Earth. This advancement has led and will continue to lead to an increased understanding of how spaceflight influences microbial population dynamics and how microbes interact with humans in space.
Understanding the microbial species present onboard the ISS, or its microbiome, may provide information that is helpful to the prevention of disease among crew members by identifying potentially harmful organisms, as well as areas of the spacecraft that are potential “hot spots” for these pathogens. Such knowledge could be used to enhance our ability to sanitize the environment and help prevent the growth of problematic organisms from getting out of hand.
Alternatively, this work can provide valuable information about how the microbiome of the ISS has reached an equilibrium with its human inhabitants as well as how these microbial populations change and evolve over time especially as new crew members come aboard. Eventually we would like to use this information to think about ways that we could modify the microbiome of a spacecraft for our benefit. For example, microbes play an important role in breaking down waste products, recycling water, and purifying the air on earth. Can we use these microbes, or their relatives, to perform the same functions on a smaller scale in a closed built environment such as spacecraft?