An ordinary weed that grows around Australia could help send humans to Mars, thanks to the work of South Australian scientists.
Duckweed is a bright green aquatic plant that grows rapidly and is packed with nutrients*. Native to SA, Victoria, WA, NSW and Tasmania, duckweed might be the key to producing food for astronauts undertaking long journeys in space.
Space horticulture* is an exciting new frontier* and University of Adelaide Associate Professor Jenny Mortimer said that many lessons could be learned about efficiently feeding a growing population right here on Earth.
Associate Professor Mortimer, who works on the duckweed project at the University of Adelaide’s Waite campus with Professor Matt Gilliham, said it was virtually impossible to take enough food on a spacecraft to embark on a multi-month journey such as the one needed to get to Mars and back.
“Most of our space travel has actually been very close to (Earth),” she said.
“The International Space Station is amazing, but it’s only 400km above the surface. If things go wrong you can get stuff up there in less than a day. You could be in Antarctica and be more remote than the ISS astronauts are.”
She said the idea of lunar* habitation* and, eventually, Martian habitation posed some unique food challenges.
“We’ve been really great at working out the physics, but we are a bit behind on the biology that goes with it,” Associate Professor Mortimer said.
“Humans are the weakest link at this point. There’s the isolation part and the psychological* component of that – humans have never been this far from the earth – and then there’s the food part.”
Associate Professor Mortimer said that with a trip to Mars taking the best part of three years, with nine months travel each way and time on the surface, a team of four astronauts would require around 10 tonnes of food.
“You can’t take that with you because you don’t have space and each kilo you take with you to space costs around $20,000,” she said.
“The current plan is that you could fly things in advance and drop it off at supply points. The problem with that is that food would have to be extraordinarily* stable. It would have to be radiation*-proof, and that constant eating of ration-pack style food is miserable.
“Astronauts can go through something called menu fatigue*, which is often seen in the military. Even though their rations are nutritious, they’ll actually lose weight because they just stop eating.”
Enter duckweed, a plant Associate Professor Mortimer thinks could be farmed on-board spacecraft – and perhaps even underground on Mars – as a nutritious source of food that could be grown vertically* using LED lighting.
“Duckweed is actually related to plants like wheat and barley,” she said.
“It was at one time a land plant and it returned to the water. What’s really fascinating about it is that it divides more like a microbe* than a plant – it splits and doubles. That means it grows really fast. It has really good protein levels and a good balance of fatty acids* and starch*, so it has a good nutrient status. So now it’s more about domesticating* it, understanding it and choosing the winning strains*.”
A future stage of the project would involve food scientists working out ways to make the duckweed palatable*.
“Perhaps they can make something that tastes like cheese or yoghurt, but that’s a research project for the next five to seven years,” she said.
- nutrients: substances like fruit and vegetables that are needed for healthy growth, development and functioning
- horticulture: science and art of growing fruits, vegetables, flowers and plants
- frontier: here a new or undeveloped field that warrants further research and development
- lunar: relating to the moon
- habitation: housing, residence, dwelling, living in a particular place
- psychological: relating to human mental and emotional states, arising from the mind
- extraordinarily: to a remarkable degree, extremely, beyond what is usual or ordinary
- radiation: energy that comes from a source and travels through space at the speed of light
- fatigue: tiredness, weariness, exhaustion, drowsiness
- vertically: standing or pointing straight up at right angles to the horizontal line
- microbe: very small living thing unable to be seen by the naked eye
- fatty acids: building blocks of fat in our bodies and in the food we eat; the body breaks down fats into fatty acids during digestion
- starch: white, granular, organic chemical that is produced by all green plants
- domesticating: cultivating, training, establishing, acclimatising
- strains: variants, different kinds and types
- palatable: appetising, edible, tasty, appealing
- Duckweed is native to Australia – where does it grow?
- How far from Earth is the International Space Station?
- What is the estimated duration for a mission to Mars?
- Which three elements give duckweed its good nutrient status?
- What could be used to grow duckweed vertically?
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1. Mars menu
Plan a daily menu for astronauts living on Mars for a year. Using plants like duckweed, not just dehydrated food in packets. Be as creative as you like and use duckweed and other plants that could possibly be grown on board a spacecraft or in the red Martian dust as part of their menu.
Time: allow 25 minutes to complete this activity
Curriculum Links: English; Science; Personal and Social; Critical and Creative Thinking
If you were a scientist working on food to sustain astronauts and humans in space for a long period of time, what sort of thing would you like to invent?
It needs to be nutritious as well as interesting – and tasty, of course!
Do you think a pill could be invented that meets nutritional needs and also fills up a human so they won’t be hungry?
Time: allow 15 minutes to complete this activity
Curriculum Links: English; Science; Critical and Creative Thinking
Imagine you were there during the event being discussed in the article or for the interview.
Create a conversation between two characters from the article – you may need or want to include yourself as one of the characters. Don’t forget to try to use facts and details from the article to help make your dialogue as realistic as possible.
Go through your writing and highlight any punctuation you have used in green. Make sure you carefully check the punctuation used for the dialogue and ensure you have opened and closed the speaking in the correct places.