Saturday, July 20, 2024

Testing antibacterial surfaces on the International Space Station – Ars Technica


Zoom in / Because particles expelled by astronauts can drift for a while before settling, most surfaces on the International Space Station eventually become subject to microbial contamination.

On June 5, the SpaceX Falcon 9 rocket They go to the International Space Station with new supplies, including scientific research equipment. Among the new scientific equipment arriving at the International Space Station are four disks covered with ultra-thin films that could play a crucial role in developing materials for future human spaceflight.

The testing of these innovative films, developed by the French Committee for Atomic and Renewable Energy (CEA), is part of an ongoing project aimed at developing antibacterial materials for space habitats.

“MATISS (Microbial Aerosol Binding to Innovative Surfaces on the International Space Station) consists of exposing these disks in the environments of the International Space Station for a long time in order to collect the bacteria that are deposited on them. These discs are then returned to our laboratories to measure the level of biological contamination,” says project manager Sebastien Roquette of the French space agency CNES.

An amazing number of microbes

With the International Space Station 400 kilometers above Earth in a near-vacuum, one might expect it to have a sterile environment. However, according to CEA’s Guillaume Nonglaton, thanks to the constant presence of astronauts, the International Space Station is teeming with bacteria and fungi.

It’s basically human bacteria [exhaled] by astronauts. Although not toxic, the bacteria can cause health care problems as well as deterioration of materials and electronics if they accumulate to form biofilms. Since there is very low gravity on the International Space Station, tiny droplets containing bacteria fly around for some time before they stick to various surfaces.

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The MATISS project was launched in 2016, and the first set of experiments served as a proof of concept. “A lot has evolved over the past seven years including materials, surface designs as well as laboratory analysis techniques. Earlier, we were only using light microscopy. Now, said Lawrence Lemmel of Ecole Normale Superior de Lyon, principal investigator of the experiment. We’ll be using X-ray fluorescence spectroscopy as well.”

For the next task, glass discs covered with antibacterial surfaces were placed in four holders, each measuring 8 x 8 x 1.5 cm. Each stand has six windows where smart surfaces are exposed to the ISS environment.

According to Lemelle, the mount is designed to minimize the risks this experience poses. “We need to avoid breaking the glass sheet, which can be very dangerous for astronauts on the space station,” she said.

prolonged exposure

Lemelle added that in previous experiments where the results were analyzed using light microscopy, they used ordinary glass plates. However, for the next experiment, which will undergo spectroscopy, the plates are made of pure glass. “It’s quartz glass made of pure silica,” she said.

For the new set of experiments, three different surfaces will be tested. One will have hydrophobic properties. The second is hydrophilic, and the third is coated with antibacterial peptides. According to Rouquette, just like the experiment currently being conducted on the International Space Station, two of the four carriers to be sent in June will be unveiled for eight months, and the other two for 16 months.

Rocket said June’s experiment would be the last in the series. “Over the past seven years or so, we have gained a good knowledge of the environment on the International Space Station and the way particles are captured and monitored. We will now look to develop test surfaces and device prototypes that can be used on spacecraft.” Our ultimate goal is to build active non-shielding surfaces. not only help astronauts, but also help them reduce the time needed to clean surfaces.”

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Besides spacewalks, instrument maintenance, and experimentation, keeping the International Space Station clean is an essential activity for astronauts. According to Rouquette, every Saturday astronauts spend hours cleaning their modules, dumping trash, and using products like cleaners and wipes to clean surfaces.

Lemelle says the antibacterial materials being developed as part of the MATISS project will address another problem. “In structures like the Space Station, there’s a lot of hardware. These hardware is stored in huge racks, which can be difficult to move. One of our goals is to have antibacterial surfaces in areas that can’t be cleaned,” Lemmel said.

Dhananjay Khadilkar is a journalist based in Paris.