Ingredients in the space salad include soybean, poppy, barley, kale, peanuts, sweet potato, and sunflower seeds, which could be cultivated aboard spaceships and supply astronauts with optimal nourishment.
Credit: University of Adelaide
“We have simulated a mix of six to eight crops that deliver all the required nutrients that an astronaut needs, which is different from what people need on Earth,” said Professor Volker Hessel of the University of Adelaide's Andy Thomas Institute for Space Resources.
“While there are dozens of crops that can fulfil an astronaut’s nutrient requirements, we needed to find those that could pack a punch and deliver the calories needed in smaller portions that could be grown in a small space.”
Professor Hessel and colleagues evaluated the daily nutrition needs of astronauts proposed by NASA experts in a 2011 research. Then, they developed a computer model to forecast the ideal plant combination for a 'space salad,' taking into account over a hundred different plants.
They chose plants that could supply an astronaut with a nutritionally full and calorically balanced plant-based diet while containing no more food mass than people usually consume on Earth. To make the cut, plants have to fulfil other tight standards in order to be included in the space salad.
To keep things simple, the plant selection was limited to less than ten distinct types. Plants must be grown in situ, leveraging space farming techniques such as hydroponics, with as little agricultural area as possible. They must also use as little fertiliser as possible in order to reduce payload.
The experiment also studied the impact of food on the astronauts' moods, including colour, taste, texture, freshness, and flavour.
“Food is such an integral part of staying healthy and happy, and there are many factors that contribute to this,” said Dr Shu Liang, a University of Nottingham researcher.
“As well as the nutritional values and ability to grow the plants in space, we also looked at other important aspects of a space diet to promote astronaut well-being, including colour, taste and eating together.”
The researchers hope to develop space farming systems and components for long-term space flights in order to suit astronauts' nutritional and psychological needs.
“Four volunteers tasted the space salad, and one concluded that they wouldn’t mind eating this all week as an astronaut,” said Karolina Rivera-Osorio, a City College of New York planetary research graduate who performed the Harmonic Psychology of a Space Salad food psychology study.
“The next stage of the research will be using digital twin modelling to design the growth chambers and systems that can grow the crops.”