Spacefood in the 1970s: warming trays holding packets of food. via
Food is high on the list of things that make humans lousy space travelers. We need to eat a lot, especially if we’re doing things like floating around repairing a space station in a bulky and unwieldy pressure suit. But the actual food is only part of the issue. That food has to be packaged. Packaging has weight, and every ounce matters when you’re launching into orbit. Recently, NASA has reevaluated the way it packages food for missions for both long and short duration flights. No detail is too small when you’re dealing with spaceflight.
The first space foods weren't very food-like, consisting of liquidy pastes squeezed out of tubes or bite sized dehydrated solids reconstituted by saliva when chewed. Meals gradually became more appetizing and reconstituted with hot water before consumption. But there’s only so many ways to prepare space food. Some things, like scrambled eggs, are freeze-dried then rehydrated onboard. Intermediate moisture foods like dried peaches have a longer shelf life and can be eaten as is.
Things like tuna and fruit are often thermostabilized, or heat processed to kill bacteria, while other foods are exposed to gamma rays or electron beams to stop bacteria from growing. A few foods like nuts and cookies can fly as they are. And then there are the fresh foods, like fruits and veggies, that astronauts have to eat within a couple of days. And all these differently prepared foods have to be packaged for flight.
The smaller Shuttle era food tray. via
Food packages are like any system on a spacecraft, though admittedly less glamorous. Every piece of the system has to be optimized; it has to be light and high quality without being prohibitively expensive to develop, produce, and launch.
NASA recently found room for improvement in the way its packages astronaut food. Tiny changes. Rehydrated food pouches, typically with lids and stored in a meal tray, have been replaced with a gusseted pouch. The new pouch (the pouch on the right in the sidebar photo) uses a different material from the tray and lid design that weighs about 200 grams less per container and decrease packaging time by 66 percent. Two hundred grams isn’t a lot – it’s less than half a pound – but it adds up when you change the packaging on potentially hundreds of meals.
But these packaging changes assume that astronauts will always be taking their food from Earth. They won’t be if we do send men to visit or colonize Mars. On missions lasting two years or longer, some of the food will be grown, processed, and prepared in space or on Mars.
With Mars missions somewhere on the horizon, NASA ran a study comparing bioregenerative (grown and processed in space) and prepackaged menus – is it more cost effective to take prepared food or the things astronauts will need to make their own?
How foods stack up in terms of caloric value and density. via
It turns out that a completely prepackaged menu is more than twice as heavy as the bioregenerative alternative, even with a significant fraction of the foods freeze-dried. The prepackaged diet was also found to have lower nutritional value; the light and heat used in sterilization does have some negative effects on the foods. But having food ready to eat does shorten the time crew have to devote to meals, freeing up more time for the things that burn calories like space walks.
It seems to be the least glamorous aspects of spaceflight that merit the most consideration. And when it comes to keeping a crew alive, no detail is more important, or less glamorous, than how to package food. Spaceflight can’t be all science and space toilets.