London: Monitoring how microorganisms adapt to the confined conditions onboard spacecraft can guarantee a safe environment for astronauts on long-duration space missions such as journey to Mars, a study suggests.
Researchers, including those from University of Edinburgh in the UK, found that apart from the crew - the main source of human-associated bacteria inside the habitat - confinement appears to be the strongest trigger shaping the bacterial community which remains highly dynamic over time.
"Until now, little was known about the influence of long-term confinement on the microorganisms that live inside habitats that may one day be used to travel to other planets, and whether the structure of the microbiota changes with time," said Petra Schwendner, from University of Edinburgh.
"Ours is the first comprehensive long-time study that investigates the microbial load, diversity and dynamics in a closed habitat - a mock-up spacecraft - for 520 days, the full duration of a simulated flight to Mars," said Schwendner, corresponding author of the study published in the journal Microbiome.
In the simulations, human-associated microorganisms, including Bacillus and Staphylococcus species were the most frequent, indicating that humans were the main source for microbial dispersal.
For example, Staphylococcus, which is frequently found in the nose, respiratory tract, and on the skin, was probably dispersed via skin flakes shed by the crew.
Although Staphylococcus will not always cause disease, it is a common cause of skin infections, especially in individuals with weakened immune systems.
To find out which bacterial species may be present in the air and on the surfaces inside spacecraft and how the composition of the microbiota may change during human habitation, a crew of six male "Marsonauts" lived inside a mock-up spacecraft, located in Moscow, from June 3, 2010 to November 5, 2011.
During the isolation period the crew members remained fully confined.
Simulating conditions during a manned mission to Mars, they followed a strict diet and schedule, which included cleaning the habitat and conducting scientific experiments.
They collected 360 microbial samples from 20 locations (nine air, 11 surface) at 18 time points, using air filters and swabs.
While a core microbiota of the same bacteria was present in all areas of the mock-up spacecraft, researchers noticed specific bacterial signatures for each individual area, indicating that microbial presence is associated with human presence as well as the type of activity that an area is used for.
Communal areas, sleep areas, the gym, and the toilet had the highest numbers and greatest diversity of bacteria, while the lowest numbers of bacteria were found inside the medical module.