# Can food be preserved by exposure to space?

Would it be possible to preserve food by wrapping them in sturdy packaging (to preserve moisture and block micrometeors) and then tossing it out of the airlock so we no longer need refrigeration space?

Since we are keeping our food inside the cabin instead of outside for space missions, there must be some complication with leaving a head of cabbage in Saran wrap outside of the airlock, right?

• Space isn't necessarily cold, direct sunlight makes things extremely hot, which is why the ISS needs cooling and not heating. – GdD Sep 5 '18 at 13:06
• Comments are not for extended discussion; this conversation has been moved to chat. – called2voyage Sep 5 '18 at 15:53
• Do you have a source for the assumption that refrigeration is used to preserve food in space? – Uwe Sep 6 '18 at 20:47

Can food be preserved in space?

Technically yes, since the general objective of food preservation is to prevent biological spoilage, which certainly happens in the cold vacuum of space. While there are many microbes that can survive in space there are no known microbes that can thrive(reproduce/multiply) in freezing 0 pressure conditions (it's like a freezer on steroids).

However, it would be exposed to a lot more direct radiation which if then brought back in for consumption could have a direct path into the body. If it is exposed to sunlight it will literally cook and outgas water mostly but also greatly accelerate the breakdown of various organic compounds thus reducing its nutritional value. That is if the container they are in doesn't explode first.

There is also the inconvenience (and efficiency loss [power & atmosphere]) of having to open the airlock every time someone wants a snack.

Edit: Since for some reason this very logical flow needs backing up:

An argument against food irradiation

The above is a decently supported argument against the irradiation of food, though far from an ironclad research paper. While it is far from an ironclad research paper I do want to point out that research on many past food safety practices are beginning to reveal longterm negative consequences of them. It's a very grey area at the moment. The article is also arguing against commercial irradiation practices which are very controlled doses. The point I wanted to draw upon was that there is already some evidence that controlled irradiation of food can be harmful, surely the uncontrolled ionizing irradiation of unshielded food in space must be even more so. This does not mean I claimed that it would be outright toxic it just means there could be a greater chance for it. I think to definitively prove anything on this aspect would require someone to float something like a banana in space for a year, bring it back and then do a comparison on compounds present.

As for nutritional loss, that happens with about every preservation method and will certainly happen here, especially if exposed to sunlight and radiation. But this post of mine has some decent links too.

NOTE: The physical construction of the container that would store said foods also has a large impact on some of the points made here. However, this aspect is technically outside the realm of the question. It should be noted that a design that enables retention of pressure could actually support microbial growth rather than inhibit it.

• I would suggest that citing mercola.com does not lend credence to an argument. It's an awful reference. – BowlOfRed Sep 5 '18 at 17:19
• Heh... For the line having to open the airlock every time someone wants a snack, I pictured a snickers commercial, "Hungry? Grab a Snicke-- WAIT NO DON'T OPEN THA--" connection lost – Magic Octopus Urn Sep 5 '18 at 17:40
• "very logical flow(s)" frequently still need backing up in Stack Exchange anyway, especially when their "very logical" nature is can't be independently established. It may be frustrating at first when people ask for sources, but after a while I think you'll see that it's not an attack or critique, but a way that people work together to build answers that are helpful and informative to future readers. Authoritative-sounding yet unsupported answers might be just fine in some sites, but in Stack Exchange it's often the case that unsourced answers are questioned and challenged. – uhoh Sep 6 '18 at 0:12
• What is the science behind "it would be exposed to a lot more direct radiation which if then brought back in for consumption could have a direct path into the body." Much or most of the ionizing radiation come from the large kinetic energy of protons, and some also from electrons and photons. Once the protons stop and pick up an electron, they are now hydrogen, and last time I checked, most of what I eat has lots and lots of that. – uhoh Sep 6 '18 at 0:12