The process of developing a microgravity-friendly food item can take months or years, says Vickie Kloeris, the food scientist who runs the ISS food-systems lab. I spoke with Kloeris about eating in space, how to pack food for a mission to Mars, and the myth of astronaut ice cream. Our conversation has been edited for length and clarity.

Marina Koren: So you got to Johnson Space Center as a food scientist in 1985. What was the state of astronaut food back then?

Vickie Kloeris: It really wasn’t all that different than it is now. Everything was shelf-stable, just like it is now. We had thermo-stabilized, freeze-dried, natural-form food, irradiated food, powdered beverages—just like we do now. But we didn’t have nearly as much variety during the Space Shuttle program because the missions were short, so we really didn’t need a whole lot of variety. When I came to work here, we were flying entrees from the MREs from the military. We don’t do that anymore because the MRE entrees are way too high in salt and fat for what we want for our long-duration crew members. The military has good reasons to have that salt and fat in there, but they are negatives for our crew members.

Koren: How do you transform a a terrestrial recipe into something that’s fit for consumption in microgravity?

Kloeris: Many terrestrial recipes, especially entrees, are not shelf-stable. The end product requires refrigeration. We don’t have a dedicated refrigerator or freezer for food on the space station, so everything that we send to orbit has to be shelf-stable. So we convert standard recipes into shelf-stable foods through freeze-drying and thermo-stabilization. Thermo-stabilization is basically canning—except we don’t do it in cans, we do it in pouches. Pouches are much lighter in weight and more efficient to stow. The tricky thing is, you can’t just take a traditional recipe and thermo-stabilize it or freeze-dry it and have it work. If only it were that simple. When we go to create a new item, it often takes multiple attempts, multiple adjustments, to end up with something that actually works.

Koren: Does microgravity affect the taste buds? Does food taste the same on the space station?

Kloeris: That depends on who you talk to. There is no scientific evidence that microgravity alters the taste of food. There is anecdotal evidence from crew members that they feel like their taste buds are somewhat dulled in orbit. Other crew members say it’s all in their head and there is no difference. But they are probably getting less aroma from the food when they eat in orbit than when they consume those same items on the ground. They’re eating out of packages rather than off a plate, so that can hinder the amount of aroma they’re getting. Plus, when you heat food on the ground, a lot of the heat rises and the aroma goes with it. When you heat stuff in microgravity, the heat can dissipate in different directions, so that has the potential to spread out the odor and have it be less intense. So that could be it. Just like when you and I are congested down here and we’re not getting as much aroma—the food’s not going to taste exactly the same.