NASA’s Artemis I launch is a major step forward in humans going deeper and spending longer in space than ever before. Future Artemis missions plan to take people to the moon and eventually Mars, which is likely to be a three-year round trip. But what will the astronauts eat? There are only so many protein bars and vitamins one can tolerate and survive on for years on end. Plants are the basis of life on Earth with their amazing ability to convert light, water and carbon dioxide (CO2) into food. Thus, a space garden is the logical solution to support humans in space.
The challenges of a space garden
Astronauts have already eaten space radish, chili peppers and lettuce grown on the International Space Station. Having freshly grown veggies in microgravity can support health and wellbeing. But there are a number of challenges in growing a flourishing space garden.
Space environments have a lot of challenges. They are CO2-rich and exposed to potentially harmful solar radiation. They also lack soil microbes, have altered gravity and need to use recycled, high-salt water. For plants to thrive in space and offer the full range of nutrients for human health, they need a redesign.
Fresh food from a space garden
After months of freeze-dried or prepackaged space food, imagine going to your space garden and picking a ripe juicy tomato and spicy chili to add to your tacos. Adding fresh produce has been a good way to improve astronaut wellbeing, supply essential vitamins and minerals, and add variety and flavor. Variety and flavor are important because low-gravity environments affect our taste and smell.
A renewable source of fresh food is essential to future long-term space missions. It helps astronauts avoid experiencing food fatigue, malnutrition and weight loss.
How to grow a space garden
Currently, astronauts grow space plants in closed boxes with low energy LED lights, porous clay “soil” with water, nutrients and oxygen supplied to roots. High-tech sensors and cameras monitor plant health. Plants did not evolve to grow in a box and use energy and resources in readiness for changes in light, temperature and disease, limiting full growth potential. So there is great opportunity to adapt plant genetics to produce faster-growing “pick and eat” food crops such as tomato, carrot, spinach and strawberry. These crops are designed to reach their maximum potential in closed, controlled environments.
A sustainable space plant future
Future plant growth systems for space will need to be entirely sustainable. That means working alongside all the other systems on a space station or a lunar/Martian base, recycling water and nutrients. All plant parts will need to be food, compost or converted into useful products such as fuels and plastics. Human waste, including urine, offers a nutrient source for plants, yet they also need to be able to cope with this salty water supply. However, there’s one plant that could be particularly suited to the task.
Duckweed may not be available at your local supermarket, but this very fast-growing plant could be in all space gardens. That’s thanks to its ability to thrive in recycled water and be zero waste, with the whole plant edible. Duckweed doubles its weight in just two days. It’s harvested continually and is high in protein, nutrients, antioxidants and vitamins. Only a few essential elements (such as vitamin B12/D) are missing that could make it a reliable base source for complete human nutrition.
One solution is for scientists to harness recent technical advances in genome editing, gene regulation and methods to analyze nutrients. Thus, they could adapt duckweed and other plants for optimal growth, minimal waste and complete nutrition. Using these methods, scientists could develop new plants that could contain proteins perfectly balanced for human digestion and use. They could also create healthy plant oils for an energy boost and soluble fiber for better gut and cardiovascular health.
Innovations brought back to Earth
Striving to explore space has brought us thousands of innovations we use in everyday life. We can expect that inventions we come up with to support humans thriving in space will deliver multiple and essential sustainability benefits to Earth. That includes an on-demand supply of nutrition and biomaterials. Experts across the globe are working together toward these dual goals, including plant biologists, engineers, food chemists, psychologists, sensory experts, nutritionists, ethicists and legal experts.
A new frontier of human achievement is on the horizon. Humans will soon not only be looking up to the night skies in wonder, but also travelling to those destinations beyond our own atmosphere. And, in so doing, planting seeds of a new way of life on Earth and beyond.
Kim Johnson, Senior lecturer, La Trobe University; Harvey Millar, Professor and ARC Australian Laureate Fellow, The University of Western Australia, and Matthew Gilliham, Professor in Plant Molecular Physiology, University of Adelaide
Bottom line: A space garden will enable astronauts to grow their own food in places like the moon and on Mars.