Plants in Space
Forget little green men. Let’s focus on the real green pioneers of space travel: plants!
Since the 1940s, plants have played a key role in space exploration, from our earliest rockets to future interstellar habitats. But did you know that spaceflight has also helped us learn more about our little green friends?
In 1946, the first living tissue in space was a handful of maize seeds (corn). Scientists wanted to see how space radiation affected living tissue, before sending up anything more substantial. Maize seeds were an important stepping-stone for humans to reach the stars 15 years later.
Space seeds have also helped bring the wonders of astronomy back down to Earth.
In 1971, the crew of Apollo 14 flew seeds around the Moon before bringing them back to plant around the world. These ‘Moon trees’ were grown alongside trees that hadn’t been to space, to compare any differences, but were also an important symbol of the technological advancements of humamankind.
Nowadays, onboard the International Space Station, a whole host of different plants are grown in the name of science. Astronauts eat about half of the produce (yes, even astronauts need their five-a-day!), but plants also help keep the station air clean.
Plants can recycle harmful airborne chemicals into safe, breathable air. Did you know that it was NASA that first unearthed the benefits of plants when it comes to air quality back in 1989? Their Clean Air Study found that certain plants remove chemical irritants such as formaldehyde and ammonia from the air, which has greatly influenced the popularity of air-filtering houseplants to this day.
Along with keeping astronauts physically healthy, plants also help psychologically. Studies have shown that nurturing and growing a little piece of Earth so far from home can help an astronaut’s environment feel a little less alien.
How do plants grow in space?
We have learnt a lot about space-based research on how plants grow in space, without the influence of gravity.
On Earth, we know that roots grow down away from the light and that shoots grow up towards it. So we can say that gravity and light tell plants how to grow. However, in space, without the effects of gravity, do the roots still grow down? How do the plants know which way is up?
Amazingly when grown in space, the roots still grow away from light and shoots towards it, which tells us that light is the main driver of plant growth direction, not gravity! Without space-based research, we would not know this, as you cannot simply turn off gravity on Earth.
In space, we can also learn how plants respond when starved of oxygen. Like us, plants need oxygen to breathe and on Earth, this is relatively straightforward. Gravity helps gases naturally mix in the air: warmer air rises whilst the colder, denser air sinks towards the ground. This continual mixing ensures that the air around us is relatively even, so we do not experience oxygen starvation when we sit in one spot and breathe.
However, in space, this mixing of gases does not occur. When a plant breathes, it uses up the oxygen around it. With no fresh oxygen mixing around the plant, it can experience local oxygen starvation, limiting the amount of oxygen available to keep the plant alive. It’s important to understand how much oxygen and overall air mixing a plant really needs to grow. One day, if we are to grow plants on other planets, with different levels of gravity, the knowledge gained in these experiments will be key.
Plants are a critical part of space travel and space travel is a significant player in plant science. The further we travel into the unknown, the better our plant knowledge needs to be. Any long-duration space mission will rely on locally-grown plants for food, atmosphere recycling, and psychological benefits for the crew.
As space exploration and rocket technology continue to advance, so too must our abilities to grow plants in unnatural environments. No matter how far we venture away from Earth, into the depths of space, we will not be able to escape eating our greens!
This material was produced in association with The National Space Centre, Leicester, UK.
Through the study of astrobiology and investigating the effects of space on plant growth and development, we can bridge two disciplines: space and plant science. Such an interdisciplinary approach not only increases our knowledge and understanding of our own research field but also that of others.
Topics like this can spark interest and conversation in people from a variety of backgrounds.
From the general public
To plant research organisations
And those inspiring the next generation of scientists
A shared appreciation for our botanical friends could go a long way in influencing future research efforts and space exploration.
