Plants in Space

Read on for the story of Dr Gioia Massa, a biologist who loves plants and dreamed of growing them in space. All words in bold can be found in the glossary at the end of the story. Questions and resources can also be found after the glossary. Happy reading!

A drawing of Dr Gioia Massa. She has long dark hair, and is wearing a lab coat. There is a small label on the coat that reads 'Veggie'. In her hands, she is holding a plant, which appears to be growing out of a brick of soil that she can hold in her hands.

This is Dr Gioia Massa. She’s a biologist from the USA.

Gioia is a special type of biologist, called a botanist. This means that she studies plants.

All her life, Gioia has been fascinated by plants and how they grow and survive. Now, she works with a special team at NASA – the branch of the American government that deals with adventures into space!

But what does plant science have to do with going into space? Surely NASA needs scientists who know about physics and space – not someone whose biggest love is small, green, leafy plants from planet Earth?

The truth is, that NASA does need physicists and astronomers, but they also need experts in lots of other things. NASA not only leads space missions, but also conducts research into how people might be able to live in space in the future. There’s a lot more to living in space than the maths and physics – including how and what people can eat and drink!

A text box. It reads: What do people eat in space? Imagine preparing to go camping. There won’t be any running water, or nearby shops, and your fresh food will go mouldy if you leave it too long. You have to plan ahead and bring alternatives. Astronauts have to make the same sort of plans for journeys into space – there’s no chance of popping into a supermarket when you’re halfway to the moon! Most foods are freeze-dried, canned, dehydrated, pre-cooked or packed in special containers that ensure that the food lasts. Astronauts can easily make these foods into a meal, simply by adding water, and cooking them in the special on-board oven. Drinks need water added to them as well: they come as powders kept in special pouches that stop the water escaping! Foods that have long lifespans can come to space exactly as they are. For example, peanut butter is the perfect space food. Astronauts can also have condiments like ketchup and mayonnaise. Fresh food can be brought too, but it needs to be eaten early in the mission before it goes bad. Fifty years ago, food in space was not very appetising, but scientists have worked hard to improve it. Nowadays, the main problems are that there are no fridges and that astronauts have to rely on food deliveries, or their own stock of food, because nothing can be grown in space. There is also a photograph of a spoon, which is covered in peanut butter.

This is where Gioia and her love of plants come in. She’s interested in how we can grow plants in space.

On Earth, we have the perfect conditions for plant life. Plants need water, gravity, food, carbon dioxide gas from the air, and just the right amount of light from the sun, to grow successfully. Luckily for us, these are all things that Earth has in abundance!

A diagram of a flower growing in the soil. Above it, the sun shines. An arrow is drawn between the sun and the flower; it says 'sunlight'. An arrow that says 'carbon dioxide' points towards the leaves, while an arrow that says 'oxygen' points away from them. The plant is rooted in the ground; its roots are also visible, and there is an arrow drawn towards them that says 'water'.

The rest of the universe is very different. When people go into space, they experience a whole new set of conditions.

The force of gravity isn’t as strong as it is on Earth, so things can float away. In a spaceship, everything has to be tied down – including the astronauts! 

Water doesn’t flow when there’s less gravity; it falls in large droplets that astronauts have to catch and break up if they want to shower or wash. There’s no soil, so plants don’t have anything to grow in, and the walls of the spaceship block out the sunlight. This all makes it incredibly difficult to grow plants.

When astronauts go on expeditions to space, their rockets must contain enough food to sustain them for the whole trip. This food has to give them all the nutrients that they need in as small a package as possible, because rockets aren’t big!

So far, no one has spent more than two years in space, and most astronauts who are in space for a long time stay at the International Space Station for about six months. That’s still a long time to go without any fresh food!

A text box. It reads: The International Space Station The International Space Station is a large spacecraft which travels in the Earth’s orbit. It doesn’t come down to Earth and go back into space like a rocket – instead, it stays in space and serves as a home for astronauts who travel to it. Here there is a photo of the International Space Station. It is made of metal and looks quite long and thin. Branching off it are solar panels; four pairs on either side of a larger middle pod. It’s also a very important scientific laboratory. Astronauts working there learn more about how people can live and work in space. This information will be very important in the future, when astronauts plan how to send people further into space than ever before.

The International Space Station can hold up to eight people at a time, and at the moment, astronauts need to bring enough food with them to ensure that they can survive the time that they want to stay for. Extra food is sent up when it’s needed, but these food delivery missions are expensive and cannot happen often.

Access to food is one of the reasons why scientists can’t send people on exploratory missions very often. The amount of time that astronauts can spend in space is limited by the amount of food they have – if they don’t get back before the food runs out, there’s no way of getting more!

If food is left for long enough, the nutrients it contains can also start to degrade. Packaged food loses its quality and flavour over time – meaning it may be inedible by the time it’s used.

Gioia was determined to change this. She knew that if astronauts were able to grow food, they would be able to stay in space for longer, eat a more varied diet, and be happier for having a little piece of Earth with them in the vast expanse of outer space.

A drawing of a spaceship on a blue background. The ship is tall and thin, with a wide central disc and a large antenna.

After Gioia became a Doctor of Plant Biology, she became a project scientist on a special NASA team with one particular goal: growing plants in space, for astronauts to eat. Perfect!

The team already knew a few things about growing plants in space. Scientists have been sending plants up on spaceships for more than fifty years, and Gioia was able to use their findings to inform her own research.

She knew that a good space plant needs to be compact, because there’s not a lot of room inside a spaceship. It also needs to produce lots of edible food that is safe for astronauts to eat. Finally, it must not require too much care, because astronauts have lots of other things to work on.

Lots of food plants, from lettuce to tomatoes, fit these ‘good space plant’ criteria. Gioia just needed to figure out how to get them to grow under the difficult and strange conditions of outer space.

Luckily, she wasn’t the only one trying to figure this out. For many years, Gioia’s friend Bob Morrow and his team had been working hard on designing a kind of sci-fi greenhouse. They called it ‘The Vegetable Production System’, or more fondly, ‘Veggie’ – a system that allows plants to survive space and grow as if they were on Earth.

Veggie is a space garden big enough to hold up to six plants. It’s about the size of a small suitcase and looks nothing like any garden you’ve ever seen!

Instead of soil, Veggie contains special “pillows”. Each pillow is made of Kevlar, a super strong and resilient material, and contains clay and fertiliser, which the plants grow in. 2-3 seeds are attached to each pillow, because some of them won’t successfully grow into adult plants.

Each plant seed is attached to its pillow using guar gum, a kind of glue that is made from guar beans. The seeds have to be glued in so that they don’t float away under the zero gravity conditions. This natural glue doesn’t harm them or prevent their growth.

The pillows help distribute water, nutrients, and air around the roots, making sure that they don’t get water-logged. Water comes straight from a special water bag, which feeds the water into the pillow and eventually to the plant roots.

Meanwhile, a fan system draws in some of the air from inside the spaceship, to provide the plant with important gases like oxygen and carbon dioxide. Carefully positioned LED lights shine over the plants, mimicking the light of the sun to allow photosynthesis.

A drawing of Veggie. It has two large, green leaves, and is resting on a small piece of clay.

Bob and his team had been refining Veggie for over a decade, but so far, no one had used it to grow plants that astronauts could safely eat or use. That’s where Gioia and her team came in.

The first successful plant to grow and be harvested in space was a red romaine lettuce called ‘Outredgeous’, grown in 2015. Since then, astronauts have grown eight different types of leafy greens in Veggie, including lettuces, mustard, and cabbage. Other plants have been grown too – in 2016, the crew of the International Space Station celebrated Valentine’s Day with a bouquet of Zinnia flowers.

A drawing of a bunch of Zinnia flowers. They are red, yellow, and pink, and tied together with a red piece of string.

Gioia was so proud of her team and all that they had achieved in creating Veggie! She had used her years of training as a botanist to create something incredible, making a real difference to the lives of astronauts on the International Space Station.

However, before they could celebrate, Gioia and her team had to be sure that the food grown in Veggie was safe to eat. It’s hard to wash vegetables in space, because you can’t get water from the tap like you would at home – it would float away!

Astronauts have to wipe their veggies instead, with specially created cleaning wipes. This isn’t as effective as washing, so to make sure no-one would get sick, Gioia wanted to ensure harmful bacteria and fungi didn’t grow on the plants in the first place.

Leaves from plants grown in Veggie are often frozen or chemically preserved, and then sent back down to Earth so that Gioia’s team can run tests on them. By comparing leaves from the plants grown in space, with leaves from plants grown on Earth, she can see whether the leaves are carrying high levels of microorganisms, which could harm the astronauts if they ate them.

A text box. It reads: Research in Space. Gioia plotted her data as bar graphs. This allowed her to easily see the difference between the number of bacteria found on the leaves of space plants compared with plants grown on Earth. Here, there is a bar graph. Number of bacterial groups per gram is on the y axis. There is a bar for space plants and a bar for Earth plants. The bar for space plants is nearly at 4, while the bar for Earth plants is close to 2. The number of bacteria found on space-grown plants was slightly higher than the number of plants grown on Earth. This result concerned Gioia. She wasn’t sure why there were higher numbers of bacteria on space plants. For the leaves to be safe to eat, the bacteria numbers needed to be lower, like those on Earth plants. Gioia worked hard to adapt the growing conditions in Veggie, so that fewer bacteria grew on the space-grown plants. Bacteria grow well in moist and warm conditions, so Gioia needed to avoid the plants becoming too wet or too hot. This was tricky - the plants still had to get enough water and warmth to grow well themselves. Gioia had to get the balance just right.
A follow-up text box. It reads: She repeated the process of counting bacteria from space-grown and Earth-grown leaves over three years. Here, there is another graph. On this one, the y axis is still mean number of bacterial groups per gram, but the x axis shows years. There are three years shown, and for each year there is a bar for space plants and a bar for earth plants. The Earth bars stay relatively the same across the years, while the bar for Space plants gets smaller, and closer to the number for Earth, each year. That shows that Gioia's work was very successful. As a result of the changes that she made, the number of bacteria on space-grown leaves declined over time, until there was very little difference between them and the Earth-grown plants.

By the third year, the mean number of microorganisms found on Veggie leaves was relatively low compared to what is usually found on farmed plants here on Earth. The Outredgeous space lettuce was now absolutely safe for astronauts to eat. Gioia was so pleased!

Now that Gioia knows that edible plants can be grown safely in space, she can start working on developing different kinds of plants that can be grown by astronauts on their space travels. Next up – tomatoes!

Perhaps one day, learning how to grow plants in space will mean that people might never have to return to Earth. We might start colonies on nearby planets like Mars and, with the designs and discoveries of teams like Gioia’s, be able to sustain ourselves without any help from Earth! Until then, growing plants is also a great way for astronauts to relax, and gives them an important reminder of Earth to take with them on their space travels, as well as some healthy nutrients.

We can all benefit from growing our own veggies, fruits, or flowers. Perhaps you should try it yourself! If you do, make sure you think about all those key conditions plants need – light, gravity, water, and food – and remember how much more accessible they are here on Earth.

The achievements of Gioia and her team will have wide-reaching consequences for space travel. They may not be astronauts, but they found an out of this world solution to the problem of growing plants in space. Extraordinary!

A drawing of the NASA logo. It is the word 'NASA' in white over a blue circle. On the circle, there are some small stars, a white ring, and a red ribbon-style arrow.

Thank you for reading!

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A text box. It reads: Glossary bacteria – microorganisms made up of a single cell. bar graphs – a drawing that displays information (known as ‘data’) as bars of different heights. botanist – a biologist who studies plants. carbon dioxide gas – an invisible, colourless gas that exists in the air all around us. Plants absorb carbon dioxide and, through a chemical reaction, use it to produce food. clay – a thick type of soil that can be moulded when wet. Lots of pots are made out of clay! compact – using very little space. When something is compact, it consists of parts that are put together closely and in a tidy way. degrade – break down and reduce in quality. dehydrated (food) – has all the water removed from it, so that it can be preserved and stored for a long time. exploratory missions – journeys which aim to discover something. In space, an exploratory mission might be one that goes to an unknown place to see what’s there, or visits another planet to look at its conditions. fertiliser – a substance which is added to soil or land to make it easier for plants to grow there. It often contains nutrients that plants need, which help them to become big and strong quickly. freeze-dried (food) – food which is preserved by a special process (freeze-drying), in which it is quickly frozen and then the ice removed. fungi – organisms that are similar to plants, but which cannot make their own food, and reproduce using spores. Mushrooms are a good example of large fungi, but they can also be microorganisms like yeast. gravity – the force by which a planet draws objects towards its centre. On Earth, gravity pulls things towards the centre of the Earth. The larger the planet is, the stronger the force of gravity there. guar beans – small beans, that can be ground into a fine powder and mixed with water to create a thick glue. Kevlar – a very strong material that is not damaged by high temperatures. LED lights – LEDs (light-emitting devices) are an electrical light source. They are often used instead of traditional bulbs, because they are more efficient and have a longer lifespan. microorganisms – living things too small to be seen with the naked eye, which are usually only seen through microscopes. Bacteria, viruses, and some fungi like yeast, are all microorganisms. NASA – National Aeronautics and Space Administration. NASA is a branch of the US government that is in charge of all science and technology which is related to airplanes or space. The first human to walk on the moon, Neil Armstrong, was an astronaut who worked at NASA, who travelled on a spaceship that they designed. nutrients – substances that all living things need, to help them survive and grow. Proteins and carbohydrates are types of nutrient, as are vitamins! orbit – a regular, repeating path that one object in space takes around another one. For example, the moon orbits the Earth, and the Earth orbits the sun. oxygen gas – an invisible, colourless gas found in the air. Plants produce oxygen, and humans need it to breathe. photosynthesis – the scientific name for the way in which green plants make food. It is a chemical reaction, in which plants use light energy to change water and carbon dioxide into oxygen and food (sugars). water-logged – a material becomes water-logged when it is full of water, and the water is difficult to move.
A text box. It reads: Hungry for more? If you’ve loved hearing about how Gioia used her love for plants to make a difference to the lives of astronauts living out in space, have a think about these questions… 1. When astronauts travel into space, they have to do lots of planning. One of the most important things to plan, is how much food and water they need to take with them. Astronauts in space each use about 1kg of food per day. It takes 3 days to travel to the moon. If four astronauts were to travel to the moon, stay there for one day, and then travel back, how much food (in kilograms) would they need to take with them? Extension: How many kilograms of food do you think you eat in a day? What about a week, a month, or even a year? 2. Fill in the blanks of the paragraph below to show how much you’ve learned! The words you need are listed at the bottom. Dr Gioia Massa is a special kind of biologist called a ________. She works at NASA, where she develops safe ways for plants to be grown in space. Her team have designed a unit for plants to grow in, which they call _______. So far, this system has been used to grow plants like _______ which astronauts can eat, and flowers called ________. Gioia has to get the conditions in there just right, to make sure that the plants get enough _________ and ________ to grow. She also has to make sure that microorganisms like ________ and _______ do not grow in large numbers, because this would make the food unsafe. Veggie light botanist lettuce water fungi Zinnia fungi 3. Astronauts have to reduce waste, so their food is always pre-prepared – no ingredients, just complete meals ready to eat! Think about how many different foods are used in your meals, and how much packaging each one comes in. How much waste do you think you create, while making food? Extension: Growing vegetables in space will help astronauts reduce the amount of waste they produce from packaging. How could you reduce the amount of packaging you use? 4. In space, astronauts wipe the leaves of space grown plants with special wipes, which kill any bacteria or fungi that are there. What do you do at home, to make sure that your veggies don’t have any sneaky microorganisms on them? 5. Think about what you’ve learnt about how plants grow, and how Veggie allows them to do this in space. Could you design your own growing chamber? It could be for a different kind of plant, like a fruit or tree, or even for an animal! Just make sure you think carefully about what the organism needs to grow, and how you could provide this in an environment where everything is able to just float away.

Resources

Gioia’s research paper: Khodadad, C., Hummerick, M., Spencer, S., Dixit, A., Richards, J, Romeyn, M., Smith, T., Wheeler, R., Massa, G. (2020). Microbiological and nutritional analysis of lettuce crops grown on the International Space Station. Frontiers in Plant Science. 11: 199.

*The graphs used in this story were adapted from Figure 2 in this paper!

More information about plants in space: 

Video: See Veggie in Space!

Video: Flowers in Space

Video: Dr Gioia Massa

More information about the ISS:

Video: A Tour of the ISS

Article: Fun facts about the ISS

More information about life in space:

Article: What is gravity?

Video: An Astronaut’s Guide to Life in Space <- an amazing playlist of videos from Space!

More information about how plants grow:

Video: How do plants get food?

Article and Resources: What is photosynthesis?

Acknowledgements

The research was produced not just by Dr Gioia Massa, but also by the other members of her research team: Christina Khodadad; Mary Hummerick; LaShelle Spencer; Anirudha Dixit; Jeffery Richards; Matthew Romeyn; Trent Smith, and Raymond Wheeler. They too deserve credit for this discovery – good science is often best done as a team.  

This story would not be nearly so good without its illustrations by the wonderful Daisy Harrison, the advice and support of Dr. Nicola Hemmings, and the pointers of Dr Gioia Massa herself. Thank you!

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