Finding ways to clean ISS and future interplanetary spaceships
According to multiple studies (see here, here, and here), a whole range of microorganisms, from bacteria (some dangerous) to fungi, have been found prospering on ISS.
The photo to the right shows a typical example of fungi growing on one of ISS’s older surfaces.
A European Space Agency (ESA) project is attempting to developing new coatings that will not only protect surfaces but act to clean them as well.
“With astronauts’ immune systems suppressed by microgravity, the microbial populations of future long-duration space missions will need to be controlled rigorously,” explains ESA material engineer Malgorzata Holynska. “So ESA’s Materials’ Physics and Chemistry Section is collaborating with Istituto Italiano di Tecnologia, IIT, to study antimicrobial materials that could be added to internal cabin surfaces.”
The IIT team has begun work on titanium oxide, also known as ‘titania’, used for example in self-cleaning glass down here on Earth, as well as in hygienic surfaces. When titanium oxide is exposed to ultraviolet light, it breaks down water vapour in the air into ‘free oxygen radicals’, which eat away whatever is on the surface, including bacterial membranes. “Bacteria gets inactivated by the oxidative stress generated by these radicals,” says Mirko Prato of IIT. “This is an advantage because all the microorganisms are affected without exception, so there is no chance that we increase bacterial resistance in the same way as some antibacterial materials.”
The application however is not as simple as painting the surface. Right now they wish to keep this coating as thin as possible (“50 to 100 nanometres, millionths of a millimetre”) so that it could even be applied to clothing, which requires using complex techniques similar to those used to make semi-conductors.
Though hand cleaning would likely be much simpler and cheaper, there are issues. First, it isn’t as easy to scrub a surface by hand in weightlessness. Second, in a closed environment like ISS cleaning materials pose a greater hazard to both the occupants and the equipment. Better if the surfaces of equipment and clothing are designed to stay clean, on their own.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
According to multiple studies (see here, here, and here), a whole range of microorganisms, from bacteria (some dangerous) to fungi, have been found prospering on ISS.
The photo to the right shows a typical example of fungi growing on one of ISS’s older surfaces.
A European Space Agency (ESA) project is attempting to developing new coatings that will not only protect surfaces but act to clean them as well.
“With astronauts’ immune systems suppressed by microgravity, the microbial populations of future long-duration space missions will need to be controlled rigorously,” explains ESA material engineer Malgorzata Holynska. “So ESA’s Materials’ Physics and Chemistry Section is collaborating with Istituto Italiano di Tecnologia, IIT, to study antimicrobial materials that could be added to internal cabin surfaces.”
The IIT team has begun work on titanium oxide, also known as ‘titania’, used for example in self-cleaning glass down here on Earth, as well as in hygienic surfaces. When titanium oxide is exposed to ultraviolet light, it breaks down water vapour in the air into ‘free oxygen radicals’, which eat away whatever is on the surface, including bacterial membranes. “Bacteria gets inactivated by the oxidative stress generated by these radicals,” says Mirko Prato of IIT. “This is an advantage because all the microorganisms are affected without exception, so there is no chance that we increase bacterial resistance in the same way as some antibacterial materials.”
The application however is not as simple as painting the surface. Right now they wish to keep this coating as thin as possible (“50 to 100 nanometres, millionths of a millimetre”) so that it could even be applied to clothing, which requires using complex techniques similar to those used to make semi-conductors.
Though hand cleaning would likely be much simpler and cheaper, there are issues. First, it isn’t as easy to scrub a surface by hand in weightlessness. Second, in a closed environment like ISS cleaning materials pose a greater hazard to both the occupants and the equipment. Better if the surfaces of equipment and clothing are designed to stay clean, on their own.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Exhibit A for unglamorous but necessary research. We can hope for some interesting spinoff developments.
Can you imagine how ‘fun’ a (near) frictionless coating would be in zero-g? “I’ve finally gotten myself to a wall. Oh crap.”
Perhaps too heavy to be practical unless perhaps applied in molecular thicknesses, but copper and brass have been found to be very antimicrobial
https://aricjournal.biomedcentral.com/articles/10.1186/s13756-018-0456-4#:~:text=In%202008%2C%20the%20United%20States,hours%20of%20contact%20%5B13%5D.
I hope this isn’t a Russian pencil Vs American pen situation… Copper has been used for millennia as an antimicrobial surface. Plus it looks pretty.
There are cleaners that are not so dangerous to the crew that can be used. Bleach, while it can be dangerous breaks down very rapidly. You can even have neutralizers nearby or built into the cleaning mechanism. You are not going to just use a rag, but something akin to a carpet cleaner would work quite nicely.
“it isn’t as easy to scrub a surface by hand in weightlessness”
Elbow grease does not work as well in free fall? Pledge™ works on Earth, why not space?
Ah. The idiosyncrasies of the new environment.
However, what do they do on submarines? This is one of the areas in which both submarines and space stations have similar problems in similar environments (confined and closed spaces, recirculated air, and cetera) and possibly similar solutions.
From the ESA article:
There are several surfaces that are hidden behind panels and racks that may also need cleaning. The cleaning job could be quite time consuming.
This topic reminds me of Don Knotts’s movie, The Reluctant Astronaut, in which he is hired by NASA as a janitor, because mission success depends upon cleanliness.
I want to know where the cockroaches are hiding. And don’t tell me there are none
Question:
Do they use any type of UV-C light in their ventilation system?
(Destroys mold and fungi at the molecular level and the effect is cumulative)
On a more fanciful note–
I’d suggest silver plating all environmental surfaces.
It’s low tech and won’t require a billion dollars to study.
Good god, give them a bottle of windex and a towel how hard is that?
Like them spending millions of dollars to design a pen that writes in outer space, only to finally decide to just use a pencil.
Something simpler IS better
To address the suppressed immune system, there is a simple way to fix that. Spin the spacecraft already. It won’t work for the station, but any interplanetary ships, which are supposed to be doing science in zero-G, will benefit from spin derived artificial gravity.
@ wayne
This is exactly what I was thinking, build a little UV bot that flies around the station zapping everything with UV when no one is around and coat any frequently touched surface with silver (or copper).
A A Ron wrote: “Good god, give them a bottle of windex and a towel how hard is that?
Like them spending millions of dollars to design a pen that writes in outer space, only to finally decide to just use a pencil.”
https://www.mentalfloss.com/article/90884/why-do-astronauts-use-space-pens-instead-pencils
What does NASA say on the subject?
https://www.nasa.gov/directorates/spacetech/spinoff/How_NASA_Astronauts_Write_in_Space
For the same reason that we don’t want graphite all over the place, we don’t use pencils in our thermal vacuum chambers for testing spacecraft. The rubber eraser shavings are pretty bad, too.
As for the Windex®, it has limited uses, and we may not want too much of the active ingredients evaporating into the air on board the ISS. This is why I wonder what is used on submarines. And every time an astronaut wipes, he is pushed away from the surface. This is why the ISS has foot restraints, so the astronauts have something to push/pull on in order to stay in place as they work at a workstation.