It seems like part of the reason might be to provide fresh vegetables in a place where they are very hard to get, to keep the researchers happy and healthy.
Nobody said they never did. I personally am thrilled by:
* It works reliably enough to be useful in the most extreme inhabitated environments. (And this habitation is artificial and very expensive)
* The logistics behind the experimental setup must have been pretty complex and all worked out. It makes me wonder whether people who manage artic stations get loaned to ESA/NASA and vv.[1]
I would say that proving a technology under those circumstances is the ultimate proof of usability, something an artificial test setup can never provide.
[1] Deploying something to space or the arctics both means that you can only fix a very limited set of problems on-the-fly. Everybody ask themselves whether they would bet someone's survival on their code or logistics.....
Given how many companies there are out here already offering container-based growing solutions, it seems like the basic principle's been tested outwith extreme environments.
Yea, a refinedment of chrischen's question would be "what did performing this easy indoor experiment in Antarctica tell us that we didn't know before?".
Not much. Maybe that there is not much point in spending money moving 100Kg of water in vegetable's form all around the world when you can put 10 gram of seeds in your bag instead.
Whilst I agree in an absolute and technical sense that lettuce is nutritionally and productively irrelevant as a food source, I don't think you can underestimate the value of fresh produce alongside whatever it is they normally eat all the way down there. You can also include [micro-]herbs and other tasty leaves and then use that experience to one day grow even more useful things.
The fact is that this is not a big deal. Is a pretty uncomplicated thing as long as you have electricity (can have light, heat and liquid water from snow). Then, all that you need is some minute seeds cheap to travel, and 2-the secret weapon in this master plan: a few humans, or as cucumbers would say, the automatic urea's dispenser of mother nature.
Lettuce and its green cousins have a mission, they are the members of the team in charge of regenerating fast and cheaply the closed circuit of water. You put urea in the "no-soil" circuit and it magically vanishes. As a nice subproduct, you can have a salad too (if you want to order a dish low in calories in one of the coldest places in earth) and also a lot of fun growing it.
https://de.m.wikipedia.org/wiki/Eisbergsalat