Cleaning in Space and Zero Gravity

Astronauts living in the cramped quarters of a space shuttle or the International Space Station can do so for weeks, sometimes as long as months at a time, facing a really challenging experience. The astronauts need to be very cautious with all potential contaminants floating in the air if they’re not careful. Dirty living in space can easily spread bacteria around, which were observed to grow a lot faster in space. This means that proper hygiene is just as important as mechanical maintenance and EVAs on the hull.

Unfortunately, cleaning and washing in space can be an equally great challenge due to low gravity. For personal hygiene astronauts bring a hygiene kit that includes razors, comb, dental floss, toothbrush and toothpaste among other items.

Astronauts work on taking showers in a large cylinder enclosed with a plastic sleeve to prevent water from floating all over, and then proceed to spray themselves with water from a nozzle inside to rinse off and then use a vacuum hose to remove all water from their skin. They also work on cleaning their hair by washing it with a rinse-free shampoo, as water can become a real problem with the multitude of electronics on board that need to be protected.

Astronauts will also need to change clothes, socks, shirts and underwear at least every two days. There are no washing machines onboard the ISS, so their clothes are disposable instead, which eliminates cleaning and frees up time for other duties on the station. As well as keeping themselves clean, astronauts need to also do their best to keep their living space perfectly clean as much as possible. Members of the shuttle rotate on cleaning duty, which involves collecting all trash from the floors, floating in the air and near the walls, cleaning the dining area of the station and other areas. To sanitize and clean astronauts make use of a biocide liquid detergent, followed by a HEPA vacuum cleaner treatment to clean all air filters. Floating particulates can easily become a problem, especially liquids since their surface tension turns them into globules floating in mid air, which easily stick to surfaces and coat them, making them very difficult to clean by conventional means. Astronauts also need to dispose of food packages by using a trash compactor and they clean their trays and utensils using antibacterial wet wipes instead of more traditional means.

NASA Testing Project Sidekick

Since the ISS and shuttles have no sewer system, the toilets make use of onboard air to flush instead of air. Air in the toilet is carefully filtered to eliminate bacteria and odors, and then recycled back into the living quarters. Solid waste on board shuttles is stored until landing, while liquid waste is expelled into space.

The crew of the ISS also needs to spend some of their day cleaning the station itself. Dust and other small particulates are a real problem since unlike on Earth, they don’t sin to the ground and float all over the place, easily getting it the eyes of the crew or clogging up the vents, potentially contaminating sensitive experiments as well. There is also exercise equipment on board that needs cleaning as well and hygiene facilities that also need to regular cleaning to stay safe to use. On the space shuttle that used to be the responsibility of the pilot due to shorter stay in space, but on the ISS this is based on crew rotation and everyone takes turns doing it.

Just like cleaning dust and dirt, astronauts need to be careful to clean condensation as well. Due to the conditions on the station, moisture can easily adhere to other moist spots and easily gets out of control. The dew point on the ISS needs to be set carefully since too much condensation can easily spell doom for the numerous electronics. While this is carefully monitored on the ISS, the space station Mir used to suffer from moisture issues all the time. The life support system on board the station is also responsible for filtering out the air through a physical and chemical process. It handles fire detection and suppression, water supply, waste management, atmospheric pressure and oxygen levels. Although the system is focused on atmospheric maintenance and support, it still helps store waste and recycles water. It uses electrolysis to create oxygen from water reclaimed from the Water Recovery System, venting hydrogen outside while using the oxygen for life support. The system also acts as a dehumidifier, as well as reducing and removing carbon dioxide using a system of molecular sieves and Sabatier, with part of the collected CO2 vented into space as well. It also generates nitrogen from tanks to complete stable atmosphere conditions. Potentially hazardous particles and excess gases are removed from the cabin air, cleaning it through air filters, charcoal beds and catalytic burners.

Wringing out Water in Space

Due to the way the air circulates in low gravity conditions, the lack of convection often led to dead air zones where bad ventilation may easily lead to carbon dioxide poisoning, but that has since been fixed and addressed to prevent it from happening. There are many challenges in maintenance and cleaning in a space station, so sometimes even the smallest mistakes can be dangerous.

Portholes need to go through routine cleaning efforts, but some of the windows of the station, such as the ones in the Destiny laboratory module need to be optically pure due to the need for constant observation. These need to be cleaned by following a special procedure to avoid any smudges at all. One unfortunate thing on the station remains clutter, since there are cables and supplies that easily exceed the available storage space on it, which means there are supplies everywhere, all the time.

Any hard waste collected after wiping and vacuuming surfaces by the crew, which helps reduce chemical and biological contamination of the station, as well as toilet waste (so-called black waste) is desiccated and placed into an unmanned Russian “Progress” logistical spacecraft alongside other solid waste. The hard waste is then burned up during atmospheric reentry.

Hopefully we are living on Earth with gravity. After founding how difficult it could be, the annoying duties we all have to deal with look more acceptable and easy to take. In regard with cleaning on Earth, workers from know best how to maintain even the hardest existing problems.

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