Astronautical Hygiene - Microbial Hazards in Space

Microbial Hazards in Space

During spaceflight there will be the transfer of microbes between crew members. Microbial exchange commonly occurs amongst astronauts. Several bacterial associated diseases were experienced by the crew in Skylab 1. The microbial contamination in the Skylab was found to be very high. Staphylococcus aureus and Aspergillus spp have commonly been isolated from the air and surfaces during several space missions. The microbes do not sediment in microgravity which results in persisting airborne aerosols and high microbial densities in cabin air in particular if the cabin air filtering systems are not well maintained. During one mission an increase in the number and spread of fungi and pathogenic streptococci were found.

Proteus mirabilis, an organism commonly isolated from patients with urinary tract infection, tends to build up on the urine collection devices. This could be a serious problem during the trip to Mars especially as some of the astronauts may be susceptible to urinary infection. In Apollo 13, the lunar module pilot suffered an acute urinary tract infection which required two weeks of antibiotic therapy to resolve.

Biofilm that may contain a mixture of bacteria and fungi have the potential to damage electronic equipment by oxidising various components e.g. copper cables. Such organisms flourish because they survive on the organic matter released from the astronaut's skin. Organic acids produced by microbes, in particular fungi, can corrode steel, glass and plastic. Furthermore, because of the increase in exposure to radiation on a spacecraft there are likely to be more microbial mutations.

Because of the potential for microbes to cause infection in the astronauts and to be able to degrade various components that may be vital for the functioning of the spacecraft it is important that the risks are assessed and where appropriate the levels of microbial growth controlled by the use of good astronautical hygiene. For example, by frequently sampling the spacecabin air and surfaces to detect early signs of a rise in microbial contamination, keeping surfaces clean by the use of disinfected clothes, by ensuring that all equipment is well maintained in particular the life support systems and by regular vacuuming of the spacecraft to remove dust etc. It is likely that during the first manned missions to the Moon and Mars that the risks from microbial contamination will be underestimated unless the principles of good astronautical hygiene practice are applied. Further research in this field is therefore especially important so that the risks of exposure can be evaluated and the necessary measures to mitigate microbial growth are developed.