Bittersweet Memories of Earth explores the role that dandelions could come to play in long-duration space missions. As a multipurpose plant, the dandelion can provide visual stimulation, nutrition and a variety of flavours to ward off the sterility of the space environment and help keep astronauts connected to their home planet.
Just over 400km away from Earth in Low Earth Orbit, astronauts in the International Space Station have a stunning view of their home planet. It looks close enough for them to reach out and touch, and their return journey takes just three hours.
Moonwalkers are committed to a longer trip - 3 days each way. But throughout it all, they can still see Earth out of the window. On a voyage to Mars, however, Earth will gradually shrink to a mere speck of light. Astronauts headed for a planet with no visible signs of life will face two years with only memories of Earth.
They can't wake up and smell the roses. They can't feel the wind in their hair, or the sand beneath their toes. For two years, they won't hear birds sing or the sound of the ocean.
Most of their food will come from packets and cans, but they will have some ability to grow plants and fresh food. Space agencies have been researching plant growth in space, for its nutritional and psychological benefits. Tending plants on long-duration missions will be good for astronauts' bodies and minds.[i]
The space crops grown so far have been chosen for entirely pragmatic reasons. They have to be easy to grow, compact plants that produce a lot of food quickly with no waste, and add vital vitamins to the pre-packed diet. With minimal time and energy for food preparation, NASA has stuck to salad crops that can be eaten raw. Leafy green vegetables top the bill, including lettuce, mizuna, kale and Chinese cabbage. With our developing expertise in space farming, peppers and tomatoes are next on the menu.[ii]
For a permanent presence on another world, the key will be to look for multipurpose crops. On Earth, the dandelion is a widespread and prolific plant. It's a tough pioneer, used to making do with limited resources. Often maligned as an overly successful weed, every part of the dandelion (roots, leaves, stem, buds and flowers) is edible. Leafy sections are a valuable source of vitamins and minerals. Dandelions have a history of medicinal use, and have even been investigated as a potential source of rubber. [iii] Their sunny yellow flowers will provide a splash of colour inside a drab spacecraft or sealed underground base.
Like astronauts' memories of faraway Earth, dandelions can be bittersweet.
Dandelion roots are bitter and make a reasonable (but caffeine-free) facsimile of coffee. Around 15 roots are needed for one cup!
Clean dandelion roots thoroughly, and dice.
Roast at 300 F (150 C) for around 40 minutes, until dry and toasted, but not burned.
Simmer the roasted root in 2 cups of water for 10-15 minutes, until the volume has reduced to 1 cup.
Strain and serve.
If available, additional spices (such as cinnamon and cardamom) can be added to the boiling water for a more flavoursome brew.
Stir-fried dandelion greens
Dandelion leaves are also bitter (similar to chicory). Still, they're a nutritional powerhouse, with beta carotene, folate, thiamine, riboflavin, calcium, iron, potassium, manganese and vitamins A, C, E, K, B6. Stir-frying is impossible on a spaceship, but a possibility on Mars.
500g dandelion leaves
2 tbsp garlic puree
1 tbsp ginger puree
Red pepper flakes, or rehydrated red chilli slices (optional)
1 tsp fish sauce (optional)
salt (to taste)
3 tbsp cooking oil
Gently heat the cooking oil in a wok or frying pan. Stir fry garlic, chillies and ginger over a low heat until fragrant.
Add the dandelion leaves, together with the fish sauce if using. Season to taste, fry until the greens are wilted, and then serve.
A vegan substitute for honey that doesn't need bees.
350g dandelion flowers
1 lemon, thinly sliced (or rehydrated lemon slices)
1 litre water
750g brown sugar
Bring the water to a boil and then add the dandelion flowers and the lemon slices, and simmer for 20 minutes, covered.
Allow to cool and then leave to steep overnight.
Drain the liquid through a sieve and discard the flowers.
Measure the volume of the liquid (expect around 750ml) and then add 1g sugar for each millilitre of fluid.
Simmer, uncovered for about 45 minutes, until the liquid has thickened to a syrupy consistency.
Pour into sterilised jars and leave to cool.
Dandelion flower fritters
100g dandelion petals
20g leafy vegetables (e.g. spinach, Chinese cabbage), finely chopped
1 onion, finely chopped (or rehydrated onion flakes)
3 tbsp dried egg, rehydrated
1/4 tsp garlic powder
Thoroughly mix together all of the ingredients except the rehydrated egg.
Add the rehydrated egg and mix to a sticky paste.
Shape into fritters, then shallow fry until golden brown and cooked through.
And Martian farmers dreading the long trip home can always make a batch of dandelion wine to enliven the journey. It takes a year to mature!
[i] Odeh, Raymond, and Charles L. Guy. "Gardening for therapeutic people-plant interactions during long-duration space missions." Open Agriculture 2.1 (2017): 1-13.
[ii] Massa, G. D., et al. "Preparing for Veg-04 and Veg-05: Improving Pick-And-Eat Food Capabilities for the International Space Station." (2017).
[iii] PFAF.org, "Taraxacum officinale." Plants for a Future. Available from: https://pfaf.org/user/plant.aspx?LatinName=Taraxacum+officinale