If we want to live on other plantets one day, we're going to have to master intergalactic gardening.

But it's not as far fetched as it might first sound. In fact, we're already making progress toward that goal.

In 2015, humans ate food grown in space for the first time, and it was exciting that Hank reported on it in a news video. Here is what the space food tasted like.

Astronauts get to do a lot of unusual things like go to space, and orbit Earth at 21,000 Kilometers per hour. And on August 10th, 3 of the international space station's crew did something even less typical. They ate space grown vegetables. This isn't the first time food's been grown in space, the Russian space station Mir had its own greenhouse and everything.

But, this is the first time orbiting astronauts have eaten it.  It was the type of red romaine lettuce called "Outredgeous". Which according to astrnaut Scott Kelly, "Tasted kinda like arugula".  But growing plants in orbit is tricky.
For one thing you have to make sure that the water and soil don't float away but you also need teach the plant which way is up because it isn't getting its usual cues. lIke the pull of gravity. 
So the lettuce was planted in what are known as Plant Pillows. Basically, bags of soil with wicks in them. The bags kept the soil in place and the wicks guided the water into the soil. Then the seeds were carfully attached to the wicks so that their root growing side was facing the soil. 
The other shoot growing side of the seed faced a panel of red and blue lights, since those are the colors plants use to grow. 
And grow they did!
The first batch was planted in May of 2014 and harvested after 33 days. 
It looked like perfectly normal red lettuce, but NASA wasn't taking any chances with unexpected space-growing side effects so, that crop was frozen and sent back to Earth for analysis. 
It seemed fine, so the second batch was planted last month in July, and it was also allowed to grow for 33 days. And then,the astronauts harvested it. 
They froze half the crop which would be sent back to Earth for more testing. 
The other half though, they got to eat. Though they had to wipe down the leaves with citric acid first. So they probably tasted a little more lemony than your standard Earth grown lettuce.

Researchers are hoping that learning how to grow plants on the ISS will help us grow plants in extreme environments here on Earth, like where there's very little water available. Plus, growing food could be useful for long-term missions, like to Mars, since they'd have to carry less of the freeze-dried stuff. Meanwhile, the researchers point out there might be psychological benefits for the crew, both from taking care of the growing plants, and from having fresh food around. In other words, space farming could just make astronauts happier. While lettuce sometimes makes up the bulk of a salad, it's not exactly a balanced meal on its own. So, we've diversified the plants we can grow in space since 2015. Here's Reed, with the description of that bountiful space harvest. If we ever want to get to the point where we're living it up in space colonies, then we've got a few big hurdles to overcome. One of the big ones is figuring out what we're going to eat. After all, we can't live off pre-packaged, freeze-dried food forever, and calling in a several-thousand-kilogram takeout order to Mars isn't exactly cheap, either. So, since the 1980s, scientists have been studying how to grow plants in space, with the hope that one day we can grow them on a moon, or even a Martian colony. But despite what certain movies might suggest, growing plants on another planet, or even somewhere closer to home, is trickier than you might imagine. If we can solve the space botany puzzle, future astronauts could benefit not just from a consistent food supply, but all sorts of plant-y goodness! Plants could also supply materials like fibers or beneficial chemicals. They might also circulate air or recycle water. Or, they could just be there to bring a bit of brightness and cheer to a pretty grey and machine-filled environment. I mean, look at how many houseplants we all bought during the pandemic. One of the first plants astronauts managed to grow in space is Arabidopsis - a cousin to cabbages and radishes, and part of the mustard plant family. It's a favored model for studying the plant world, because its relatively small genome and fast life cycle make it easy to work with.

Arabidopsis was first grown in space in nineteen eighty-two on board the Russian space station. But NASA scientists on board the International Space Station have grown a whole host of other foods since then using their vegetable production system dubbed 'Veggie'. Their safe-to-eat bounty has included: Chinese cabbage, red romaine lettuce, mizuna mustard plants and a mini form of bok choy.
NASA also has another fully automated version of 'Veggie Onboard' called 'The Advanced Plant Habitat'. It uses censors, cameras, lights, and water and gas reserves that can monitor and control watering, temperature and oxygen and carbon dioxide levels inside its enclosed chamber automatically. 
Using The Advanced Plant Habitat, astronauts have been able to grow dwarf wheat and, in twenty tewnty-one, edible peppers!
All of those growing experiments have been really important because they have told scientists a lot about how plants grow in the conditions of space.
Take something like gravity, for example. The ISS experiences microgravity thanks to its state of free fall. The moon has one sixth of Earth's gravity, and Mars has a bit more, but still only around sixty two percent of Earth's. 
So one of the first things researchers wanted to find out is whether plant roots still grow down when they don't have the cue of gravity to guide them. Turns out plants seem to do just fine using strong light as a guide instead; with shoots growing up towards the light and roots away from it. But, the lack of gravity can wreak other kind of havoc on plants.
Low gravity means that water behaves weirdly around plant roots. In microgravity it forms bubbles which can surround the roots and, as you know, if you've ever over-watered a house plant, being too wet is bad for them. That's why plants on the ISS grow in little pillows of clay where the gaps in the clay trap just enough water, and a little bit of air, so that the roots can absorb the H2O without being waterlogged.

Now growing plants on board a high-tech space station is one thing but growing them on the surface of the moon, or a planet, is another. 
It wasn't until 2019 that cotton seeds aboard a canister on China's Chang'e-4 lander sprouted on the far side of the Moon.
As well as the cotton seeds, this thermos-sized canister housed potatoes, canola, yeast, fruit fly eggs and the old favourite - Arabidopsis.
The idea was these organisms would form their own 'mini biosphere', with the plants breathing out oxygen and taking in carbon dioxide made by the fruit flies and the yeast keeping the C02 and O2 levels in check.
The canister itself was supplied with temperature controls and a system that watered the plants when told by ground control.
Of all the seeds we only know for sure that the cotton sprouted and, even then, their life was pretty short.
A breakdown in the biosphere's temperature control exposed them to the -190 degrees Celsius lunar night. Researchers did still learn something from the super-short experiment, though, which is that plants, at least cotton seeds, can sprout in the harsh conditions on the moon.
See, although the space station is technically in space, it's only about 400km away from Earth and still a pretty controlled environment, shielded from the extreme temperatures and cosmic radiation found on the Moon. 
So, before landing the canister on the Moon, it was really hard to simulate the true conditions of space. And although the experiment didn't go according to plan, in that researchers never got a chance to see if the organisms could work together in a self-sustaining mini biosphere, learning what went wrong could help scientists build more resilient plant environments in the future.
In addition to putting plants in an environment that suits them, researchers also need to investigate how to make the plants themselves more resilient to the harsh space envirnment. 
One way to do that might be through genetic engineering. 

By tweaking the plants DNA, botanists could make them more resilient to the stress of space flight, make them grow better in low-oxygen conditions or make their roots shorter so that they can fit more plants into a small space. We might even be able to go as far as to genetically engineer plants to grow in lunar or martian soil. 
Maybe part of the reason the cotton seeds were the things to sprout is because they were genetically engineered to be more hardy and insect resistant here on Earth. 
Scientists have already grown plants like tomatoes and leeks on Earth, using soil that's made to simulate the stuff you'd find on the Moon or Mars; which might still be a long way from actually growing them on Mars but it's still one small step for human-kind, and could mean we'll be munching on space veg on our way to the red planet in the future. 
We have methods to keep plants safe from extra-terrestrial conditions, but it is still nice to know that we still have cotton even if those protective measures break down. After all, the future growing stuff in space could involve using it for more than food. Here's how growing fungi in space could keep us safe from radiation, make our crops more plentiful and provide the literal building blocks for our homes. 
Many people dream of a future in which humans explore and even live in space. New technologies and even new materials will definitely be required. But, in our quest to explore the cosmos, we shouldn't count out help from Mother Nature because it has created a spectrum of life full of remarkable traits. And, even among those, few kinds of life are as diverse as fungi. 
Like, some of them even grow from radiation and NASA's looking as those organisms to help our ultimate survival problems. So, let's take a look at some of the fungus-among-us and how they're helping put us humans into outer-space. Perhaps the most important challenge for our long-term habitation of space is radiation; because up there, the Earth's atmosphere and magnetic field can't protect us from the harmful effects of the Sun. 

NASA estimates that an astronaut on a one-year trip to Mars would absorb about 66 rem of radiation. 
That's about 100 times more than what we experience here on Earth and about 2/3 of the current NASA lifetime allowance. 
So, from a radiation perspective, a year on Mars is like a lifetime on Earth, making our life on Mars, well, not great. 
That's where fungi might be able to lend a hand. See, some species of fungus aren't just resistant to radiation; they can grow from it. 
Certain species can survive in areas of extreme radiation, like the failed Chernobyl nuclear reactor. In fact, some researchers believe they can derive energy from these environments through a process called 'radiosynthesis'. 
Think of it as like photosynthesis but instead of capturing energy through visible light, they take it from gamma radiation. And these fungi are hypothesised to do this using a special adaptation of a very common chemical - melanin. 
You might know melanin as the substance that's responsible for skin colour. Researchers are still studying how this works, but some hypotheses are that this intense radiation helps the melanin move electrons around more efficiently to harness energy. And, as they move, they also absorb some of the radiation as it passes through the fungus. 
So NASA scientists wanted to test if the fungis melanin would also absorb radiation from space. In 2019 they flew an experiment to the International Space Station to test the properties of a mixture of plastic and fungal-derived melanin and they expect to have results over the next few years.
And, the U.S. Naval laboratory will be sending melanin-rich fungi to orbit the Moon as part of the upcoming Artemis-1 mission, scheduled to launch in early 2022. But the hopes are that they could use these fungis melanin to shield not only astronauts, but also people on Earth from harmful radiation. But that's not all. 
Unrelated to its radiation absorbing melanin properties, one of these fungi species might also help astronauts in other ways.

Like producing the food they need for a long space voyage. To maintain a healthy diet, future explorers will need to eat plenty of fruits and vegetables, just like we should on Earth. Unlike on Earth though, the space needed to grow all that good stuff will be extremely limited.

So to grow enough food to keep a crew fed, plants need to be able to grow quickly and efficiently. In a paper published in 2018, researchers found that crops grew faster and were more plentiful after exposing them to a certain fungal species. Two years later, a study conducted onboard the ISS by the US Department of Agriculture found that the effect also works in space, with treated crops growing at rates two to five times faster than normal. 

And when sugar was added into the mixture, that growth rate could explode up to 25 times faster than usual. What's more, the plants didn't just grow faster, they produced more. Pepper plants used during the experiment produced up to three times more peppers than those without the fungus. Their stems were more substantial, their leaves were larger, and even their roots were expanded.

That's exactly the kind of efficiency necessary to make farming in the confines of a spacecraft a real possibility. And this super speed growth seems to be the result of gases emitted by the fungus and absorbed by the plants, but exactly what those gases are and why they work remains a mystery.

And there's even still one other way that fungi could help humanity survive outside of Earth. They could be the building blocks of our structures. See, NASA's prototyping the use of string-like parts of a fungus called 'mycelia' to form the structure of future lunar and martian habitats. Building materials made in part from mycelia have proven to be quite strong here on Earth. 

And on Mars, they could allow astronauts to grow new material to build with rather than lugging it from Earth. And if that fungus happens to be rich in melanin, the mycelia woven in could also provide additional protection from radiation. So taken together, fungi are starting to seem like the answer to many of our space problems.

And why not? The idea that exploring and living in space is pretty remarkable. Relying on Earth's most remarkable forms of life just kind of fits right in.

[Caitlin]: If we could grow a lot of the stuff we need to live in space when we get there, it would make living in other worlds way more feasible. Thanks for joining me today. I know you're curious about this stuff. And why should grown ups get to have all the fun? That's why also have a channel for kids.

If you know some kids wondering what space snacks taste like, you can send them to our Scishow kids video about growing food on Mars. You can also join our community and support this channel at patreon.com/scishowspace.

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