On June 5, a SpaceX Falcon 9 rocket blasted off to the International Space Station with latest supplies, including equipment for scientific research. Among the many latest scientific gear that has arrived on the ISS are 4 tablets covered with extremely thin movies that might play a vital role in the event of materials for future human space flights.
Testing these progressive movies, which were developed by the French commission for atomic and renewable energy (CEA), is an element of an ongoing project geared toward developing antibacterial materials for space habitats.
“MATISS (Microbial Aerosol Tethering on Modern Surfaces within the International Space Station) consists of exposing these tablets within the ISS environments for a very long time with the intention to collect the bacteria that gets deposited on them. These tablets are then returned to our laboratories for measuring the extent of biocontamination,” says project manager Sebastien Rouquette of the French space agency CNES.
A surprising variety of microbes
With the ISS being 400 km above the Earth in a near-vacuum, one might expect it to have a sterile environment. Nevertheless, based on Guillaume Nonglaton of the CEA, due to the constant presence of astronauts, the ISS is teeming with bacteria and fungi.
“It’s mainly human bacteria [exhaled] by the astronauts. Although they usually are not toxic, the bacteria may cause health care issues in addition to degradation of materials and electronics in the event that they accumulate to form biofilms. Since there could be very low gravity within the ISS, the microdroplets containing bacteria fly around for quite a while before attaching to different surfaces,” he said.
The MATISS project was launched in 2016, and the primary set of experiments served as proof of concept. “So much has evolved over the past seven years including within the surface materials and designs in addition to laboratory evaluation techniques. Earlier, we were using only optical microscopy. Now, we will likely be using X-ray fluorescence spectroscopy, too,” Laurence Lemelle of Ecole Normale Supérieure de Lyon, who’s the experiment’s principal investigator, said.
For the upcoming mission, glass tablets covered with antibacterial surfaces have been placed in 4 holders, each measuring 8×8×1.5 cm. Each holder has six windows where the smart surfaces get exposed to the ISS environment.
In line with Lemelle, the holder was designed to reduce the chance posed by this experiment. “We’d like to avoid the breakage of the glass lamella, which could be very dangerous for the astronauts on the Space Station,” she said.
Long exposure
Lemelle added that for earlier experiments where the outcomes were analyzed using optical microscopy, they used regular glass sheets. Nevertheless, for the upcoming experiment, which will likely be subjected to spectroscopic evaluation, the sheets are manufactured from pure glass. “It’s quartz glass manufactured from pure silica,” she said.
For the brand new set of experiments, three different surfaces will likely be tested. One could have hydrophobic properties; the second is hydrophilic, while the third is coated with antibacterial peptides. In line with Rouquette, identical to the experiment currently running on the ISS, two of the 4 holders that will likely be sent in June will likely be exposed for eight months, and the opposite two for 16 months.
Rouquette said the June experiment will likely be the last on this series. “Over the past seven years or so, we have now acquired good knowledge of the environment within the ISS and the solution to catch and observe particles. We are going to now be trying to develop test surfaces and prototypes of hardware that might be utilized in spacecraft,” he said. “Our eventual goal is to construct lively surfaces that might not only protect astronauts but in addition help them in reducing the time needed for cleansing the surfaces.”
Together with spacewalks, hardware maintenance, and conducting experiments, keeping the ISS squeaky clean is an integral activity for astronauts. In line with Rouquette, every Saturday, astronauts spend hours cleansing their modules, trashing waste, and using products similar to detergent and wipes to wash the surfaces.
Lemelle says that the antibacterial materials being developed as a part of the MATISS project will address one other problem. “In structures just like the space station, there may be a whole lot of instrumentation. This instrumentation is stored in huge racks, which could be difficult to maneuver. One among our goals is to have antibacterial surfaces in regions that can’t be cleaned,” Lemelle said.
