[♪ INTRO]
Years into the future, when the first children grow up on Mars or the Moon,
parents might have to update the story of the three little pigs.
In one version of the classic fairytale,
three pigs make their houses out of straw, wood, or clay bricks.
But on September 10th, in a paper published online
in the journal Materials Today Bio, scientists revealed a way that astronauts could
make their homes out of something different.
They could use Martian or lunar dust along with an ingredient...from human blood.
This idea came up as part of an ongoing quest to get around one of the trickiest
parts of space exploration: Getting into space takes a lot of fuel,
and the more mass you’re trying to get up there,
the more fuel and the more money you need.
So, scientists have been looking for ways to
utilize materials already on the worlds we might visit.
For instance, it would be really handy if we could build housing out of the stuff
that’s just sitting around on the Moon or Mars.
Because taking a single brick to Mars would cost an estimated two million dollars.
And you can’t live inside of a single brick,
so this is the problem that the team was trying to solve.
They explored making a kind of concrete based on
simulated lunar and Martian regolith, which is the loose, dusty,
rocky stuff that covers the surfaces.
So they mixed those simulated regoliths with various binders to see if they could
support the weight of a building, plus nasty environmental factors
like meteor strikes and the lack of air pressure.
Now, this is not the first time a group has suggested making regolith concrete.
But the reason this team made headlines is
because of what they suggested using as a binder.
Instead of using a synthetic chemical, which might require fancy equipment and
heavy equipment to create, they explored using
binders from the astronauts’ bodies.
Because, theoretically, like we’re already gonna be there.
They dubbed the resulting compound AstroCrete,
and it includes a protein found in human blood, called human serum albumin.
In their study, the team made this concrete with a pretty simple process:
They compacted their simulated regolith in a syringe,
then infused it with water filled with this protein
to make pellets roughly 30 millimeters long.
They also tested what would happen if urea was added to the mix.
Urea is excreted in our sweat, tears, and… yes, urine, and it’s a denaturant.
That means it would change the blood protein’s structure,
hopefully in a way that would provide extra strength to the concrete.
And it did! The best sample the team tested was made of simulated Moon regolith,
and was actually stronger than standard concrete on Earth.
The urea also increased the AstroCrete’s density,
which would make it a bit better at blocking high-energy radiation from space.
All that said… you might see one of the problems with this whole idea.
To make a lot of AstroCrete, you would need to harvest a good amount of
this blood protein without, you know, threatening the health
or general well-being of the astronauts.
If nothing else, the team did estimate that a six-astronaut mission would be able to
provide enough blood protein and urea for
1800 bricks of AstroCrete over a 72-month mission.
But also, more research needs to be done on things like how often astronauts
could donate plasma before we start planning AstroCrete buildings.
And that number of bricks would not be enough to build a whole settlement,
but it maybe could be helpful in expanding existing buildings.
Then, if more concrete was needed beyond that, the researchers suggested that,
building on their own previous research,
spider silk could be used instead of human serum albumin.
They also note that other researchers have done significant work with
the cow version of the same blood protein.
Then again, both options still come with their own challenges:
You either have to pay for powdered spider silk or cow protein to be sent to Mars,
or both, or you have to try to rear animals off Earth!
Also, when it comes to Mars specifically,
AstroCrete is not quite ready for primetime.
The concrete made with the analog lunar regolith may have been great,
but the Mars-based AstroCrete was not as strong as regular Earth concrete.
It’s possible that further processing the Martian regolith could help somehow,
but that hasn’t been studied yet.
In general, we’ll also need to test how long it takes
for this concrete to break down from erosion.
Because although wind on the Moon isn’t really a thing thanks to
the lack of an atmosphere, winds on Mars can reach
more than 100 kilometers per hour during a dust storm.
Overall, AstroCrete still has a ways to go, but then again,
we’re not ready to start living on the Moon or Mars any time soon, anyway.
So, there’s plenty of time to keep working on this idea.
Also, even if AstroCrete doesn’t end up being part of humanity’s future,
research like this continues to push the boundaries of
what we know about making habitats that are literally out of this world.
And something else that is also out of this world
is this month’s space pin featuring Luna 16.
After six attempts this spacecraft brought home the Moon
and now you can bring Luna 16 to your home.
The pin showcases the bubbly spacecraft and it glows in the dark!
Be sure to snatch it before September ends at DFTBA.com/SciShow.
Because when October rolls around, that pin will
never be available again and we will have a whole new pin ready for you.
[♪ OUTRO]