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These days, it seems like we’re closer than ever to transporting humans around the solar system.
But getting people into space is one thing; keeping them alive is a whole different ball game.
It’s the difference between exciting new exploration and just a really expensive way to die.
Among a bunch of other things, one of the most important elements to sustaining life
beyond Earth is making sure we’re really well fed.
So far, a lot of thinking has gone into ways to grow food in places like the Moon or Mars,
but those are just single locations in the vast solar system.
What we really need is a cosmic food court capable of feeding us wherever we go.
And for that, we might want to look to the asteroid belt!
All this concern about growing food is necessary because of our pesky friend gravity.
It takes a ton of energy to escape the Earth’s gravitational pull, and even with reusable
rockets, getting to space can be pretty pricey.
Take SpaceX’s new Falcon Heavy rocket, for instance.
It’s among the most efficient rockets today, but pack it full of food for Mars and you’d
be paying more than $5,000 per kilogram.
For a one-off trip, maybe that makes sense, but to settle humans on Mars it would cost
$5,000 per kilogram per person, for the rest of their lives.
That’s just not sustainable.
Conveniently, though, it turns out we’ve solved this problem before, like a lot, — and
with something really simple: seeds.
One obvious example is when Europeans crossed the Atlantic to settle in North America, they
didn’t bring a lifetime’s worth of food with them.
Instead, they brought the means to create more food once they got there.
They farmed.
In that example, North America already had people who were farming, but it’s still
a good tactic for getting food to space!
Once we figure a few things out, this could work for a place like Mars, where settlers
could grow food right on the surface.
But if we sent people to Jupiter’s moon Europa or Saturn’s moon Titan, things would
get more complicated.
Those trips would last for years, and because of their surface conditions, there’d be
nowhere to farm right when we got there.
That’s where asteroids come in.
Since they mostly orbit between Mars and Jupiter, they could be a convenient gateway to the
outer solar system.
They’re also a lot smaller than even the Moon, meaning they have dramatically less
gravity to escape, which would greatly reduce the food’s cost to ship.
Ceres, which is often considered the largest asteroid, has about 3% of Earth’s surface
gravity, and most others have thousands of times less than that.
Most importantly, though, some kinds of asteroids may already contain many of the most important
nutrients for life.
They’re called carbonaceous asteroids, or sometimes C-types.
C-types are probably the most common kind of asteroid, but they’re remarkably difficult
to study because of their appearance.
They reflect just a tiny percentage of the Sun’s light, and probably look more like
coal than whatever you’re picturing right now.
I say probably because we haven’t really been able to study carbonaceous asteroids
in great detail.
Instead, most of what we think we know about them comes from meteorites called carbonaceous
chondrites, which are likely chips of C-type asteroids.
Based on the name, you might think they’re mostly made of carbon.
But they only contain a small percentage of carbon at best, along with nitrogen, potassium,
and phosphorus.
Sounds like fertilizer, doesn’t it?
Amazingly, deep inside these meteorites, we’ve also found evidence of some of the same amino
acids that are inside our bodies, as well as other organic compounds.
To top it all off, some carbonaceous chondrites contain up to 20% of their weight in water.
Some of that was surely absorbed here on Earth, but many meteorites contain evidence suggesting
they formed in the presence of liquid water, too.
These useful elements were even enough for one chemist to grow plants in crushed up meteorites!
But hold your space tractors, because we’re not ready to start farming just yet.
Ironically, the main obstacle to growing plants on an asteroid might be one of its main benefits: microgravity.
Space station and Space Shuttle experiments going back decades have tried to grow plants
in zero-g with only limited success.
Even though the plants often grow well, the seeds they produce rarely create a healthy
second generation.
Which is obviously key, if you’re looking to set up a long-term farming operation.
But some recent experiments are finding more success, so it’s not all bad news.
And, of course, we’d still need to provide the right atmosphere, enough sunlight, and
protection from cosmic radiation, so this is an idea for the long haul.
But if we can get it right, the dividend could be awesome, in the true sense of the word.
One estimate suggests that the total population of C-type asteroids could sustain a billion
humans for the rest of the Sun’s lifetime -- no matter where they are.
Fortunately, we’re also about to reach an important milestone in all of this.
This summer, Japan’s Hayabusa2 spacecraft will reach the asteroid Ryugu, marking the
first time we can properly study a C-type asteroid up close.
What’s more, Hayabusa2 will also scoop up a piece of its surface and return the sample
to Earth by late 2020.
So, who knows?
Maybe that could start the clock towards a future fed by asteroids.
Thanks to Blue Apron for sponsoring this video.
And for giving me the confidence to cook pork chops for the first time!
I did not grow up in a cooking house, so even though I like to try new foods, I don’t
know how to bring them into being in my kitchen.
And it’s a problem because my boyfriend is a really good cook and he’ll ask me to
help him season things and I just panic and put a ton of cumin in EVERYTHING.
But the other night I made pork chops with quick pickled cabbage and potato salad with
buttermilk dressing.
Blue Apron recipes are super straightforward and explain everything, so you’re learning
to cook while making a really good meal.
And, if you get nervous in the kitchen, like I do, it’s really comforting to have those
step-by-step instructions.
I didn’t overthink, or over season, anything, and it turned out delicious.
So to build your own confidence in the kitchen, check out Blue Apron at the link in the description.
Prices start at $7.49 per serving, and the first 50 SciShow viewers to sign up, get $50
off your first two weeks!
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