A Microbial Monitoring System Demonstrated on the International Space Station Provides a Successful Platform for Detection of Targeted Microorganisms

Migration of surface-associated microbial communities in spaceflight habitats

Astronauts are spending longer periods locked up in ships or stations for scientific and exploration spatial missions. The International Space Station (ISS) has been inhabited continuously for more than 20 years and the duration of space stays by crews could lengthen with the objectives of human presence on the moon and Mars. If the environment of these space habitats is designed for the comfort of astronauts, it is also conducive to other forms of life such as embarked microorganisms. The latter, most often associated with surfaces in the form of biofilm, have been implicated in significant degradation of the functionality of pieces of equipment in space habitats. The most recent research suggests that microgravity could increase the persistence, resistance and virulence of pathogenic microorganisms detected in these communities, endangering the health of astronauts and potentially jeopardizing long-duration manned missions. In this review, we describe the mechanisms and dynamics of installation and propagation of these microbial communities associated with surfaces (spatial migration), as well as long-term processes of adaptation and evolution in these extreme environments (phenotypic and genetic migration), with special reference to human health. We also discuss the means of control envisaged to allow a lasting cohabitation between these vibrant microscopic passengers and the astronauts.

Solar ultraviolet light collector for germicidal irradiation on the moon

Prolonged human-crewed missions on the Moon are foreseen as a gateway for Mars and asteroid colonisation in the next decades. Health risks related to long-time permanence in space have been partially investigated. Hazards due to airborne biological contaminants represent a relevant problem in space missions. A possible way to perform pathogens' inactivation is by employing the shortest wavelength range of Solar ultraviolet radiation, the so-called germicidal range. On Earth, it is totally absorbed by the atmosphere and does not reach the surface. In space, such Ultraviolet solar component is present and effective germicidal irradiation for airborne pathogens' inactivation can be achieved inside habitable outposts through a combination of highly reflective internal coating and optimised geometry of the air ducts. The Solar Ultraviolet Light Collector for Germicidal Irradiation on the Moon is a project whose aim is to collect Ultraviolet solar radiation and use it as a source to disinfect the re-circulating air of the human outposts. The most favourable positions where to place these collectors are over the peaks at the Moon's poles, which have the peculiarity of being exposed to solar radiation most of the time. On August 2022, NASA communicated to have identified 13 candidate landing regions near the lunar South Pole for Artemis missions. Another advantage of the Moon is its low inclination to the ecliptic, which maintains the Sun's apparent altitude inside a reduced angular range. For this reason, Ultraviolet solar radiation can be collected through a simplified Sun's tracking collector or even a static collector and used to disinfect the recycled air. Fluid-dynamic and optical simulations have been performed to support the proposed idea. The expected inactivation rates for some airborne pathogens, either common or found on the International Space Station, are reported and compared with the proposed device efficiency. The results show that it is possible to use Ultraviolet solar radiation directly for air disinfection inside the lunar outposts and deliver a healthy living environment to the astronauts.

The Development of a 3D Printer-Inspired, Microgravity-Compatible Sample Preparation Device for Future Use Inside the International Space Station

Biological testing on the International Space Station (ISS) is necessary in order to monitor the microbial burden and identify risks to crew health. With support from a NASA Phase I Small Business Innovative Research contract, we have developed a compact prototype of a microgravity-compatible, automated versatile sample preparation platform (VSPP). The VSPP was built by modifying entry-level 3D printers that cost USD 200-USD 800. In addition, 3D printing was also used to prototype microgravity-compatible reagent wells and cartridges. The VSPP's primary function would enable NASA to rapidly identify microorganisms that could affect crew safety. It has the potential to process samples from various sample matrices (swab, potable water, blood, urine, etc.), thus yielding high-quality nucleic acids for downstream molecular detection and identification in a closed-cartridge system. When fully developed and validated in microgravity environments, this highly automated system will allow labor-intensive and time-consuming processes to be carried out via a turnkey, closed system using prefilled cartridges and magnetic particle-based chemistries. This manuscript demonstrates that the VSPP can extract high-quality nucleic acids from urine (Zika viral RNA) and whole blood (human RNase P gene) in a ground-level laboratory setting using nucleic acid-binding magnetic particles. The viral RNA detection data showed that the VSPP can process contrived urine samples at clinically relevant levels (as low as 50 PFU/extraction). The extraction of human DNA from eight replicate samples showed that the DNA extraction yield is highly consistent (there was a standard deviation of 0.4 threshold cycle when the extracted and purified DNA was tested via real-time polymerase chain reaction). Additionally, the VSPP underwent 2.1 s drop tower microgravity tests to determine if its components are compatible for use in microgravity. Our findings will aid future research in adapting extraction well geometry for 1 g and low g working environments operated by the VSPP. Future microgravity testing of the VSPP in the parabolic flights and in the ISS is planned.

Bacterial bioburden and community structure of potable water used in the International Space Station

The control of microbes in manned spaceflight is essential to reducing the risk of infection and maintaining crew health. The primary issue is ensuring the safety of a potable water system, where simultaneous monitoring of microbial abundance and community structure is needed. In this paper, we develop a flow cytometry-based counting protocol targeting cellular flavin autofluorescence as a tool for rapid monitoring of bacterial cells in water. This was successfully applied to estimate the bacterial bioburden in the potable water collected from the International Space Station. We also demonstrate the efficacy of the MinION nanopore sequencer in rapidly characterizing bacterial community structure and identifying the dominant species. These monitoring protocols' rapidity and cost effectiveness would contribute to developing sustainable real-time surveillance of potable water in spaceflight.