What's for Dinner?
Explorers are set to launch into space for a very long journey, and you can guarantee that scientists will have explored many ways to produce a reliable food source for the crew. The ability to store high-calorie, high-nutrient food rations for months, or even years, would have been thoroughly investigated at this point. I think it's safe to say that any space mission would always include stored food. The biggest hurdle for the crew may be creating palatable and healthy crops that are sustainable for traveling over very long periods in space. This need would be of high importance for any long distance travel, so you can understand why NASA, and now China, are exploring ways to grow and sustain plants, while traveling through space.So what kind of plants would we bring?
Obviously, our focus would be on plants that are palatable, and edible in many different ways. A plant that can produce edible roots, stems, and leaves, while also providing fruits, and/or seeds would be of the highest value. When we consider that most plants around us are not palatable, and of the subset that we use for crops, there are not many that fit this description. Most plants are harvested for a single part, and the rest of the plant is either composted or fed to livestock. For example, crops like corn, tomatoes, wheat, potatoes, squash are all harvested for a single part. This doesn't even consider the size and space restrictions of growing these crops as they currently exist. Some plants, such as those in the mustard family (Brassicaeae), have varieties with edible roots, buds, leaves, and seeds. For example, Brussels sprouts, kale, turnip, and cabbage all come from this family; even the same genus. These are compact plants, with a short life-cycle, and are nutritious; plus we know a lot about the genetics of this family from work on Arabidopsis
(I hope space explorers enjoy bitter crops). In the end, we may need to bio-engineer plants to meet these demands, since the working list is so limited.Which growth systems would work best?
These plants would need to be able to survive artificial growing systems, possibly in reduced gravity environments. Plants evolved many passive mechanisms that are dependent on the specific gravity of Earth, and low gravity environments can interfere with gas exchange in leaves and roots, as well as water movement through the plant. Nothing can be taken for granted, and we can assume that researchers will find low energy solutions to these problems. For example, explorers might opt for some kind of closed hydroponics systems, that is constantly replenishing water, minerals, and gases (see below). Research has shown that this is the most efficient way of growing concentrated plants on Earth, but this system requires a plant can handle a non-soil environment, which (once again) can be challenging for many of our favorite food crops. Symbiosis goes a long way...
Another possibility could be creating soils with robust fungal and bacterial components. It appears that NASA scientists are already looking at the relationships between plant roots and bacteria while in space with the Symbiotic Nodulation in a Reduced Gravity Environment Project. I would guess that there are researchers are also looking at fungi, since most plants also have an association with soil fungi, called mycorrhizae (see image below). Researchers would want to maintain this mutualism to insure the healthiest, fastest growing plants possible. In return, the explorers would be supplemented with the occasional mushroom or morel, the “fruiting bodies” of these symbiotic fungi. Although beneficial, keeping these relationships would be a critical, but daunting challenge.Mustard greens again?!?!
Lastly, these explorers would want to create an environment that produces a diversity of plant types to enhance their palate and health. They may have to deal with the doldrums of space, but food would bring a desirable highlight to the “day”. Creating such a diversity could also prove difficult, and the explorers may find themselves producing a type of permaculture, called an edible forest system, such as those found on Earth (see below). These systems create a tiered approach, by which rows of different species are also structured so that taller fruit or nut producing trees, shade shorter fruiting producing shrubs and vines, which border smaller herbaceous crops that we see on farms. This diversity would still seem limited after months in space, but it most travelers, and in old times, would learn to cope with the availability.In the end
, any system that explorers adopt would have steep challenges: finding or creating diverse crops with diverse uses that can survive low gravity and artificial environments. The crew on this journey would need to have personnel with a strong background in agriculture in order to insure the survival during journey, and the establishment of crops on the new world... that's our next stop.