What do you think of when you imagine a space colony?
You probably envisage a city of bubble domes extending off into a red horizon or a sleek
steel metropolis.
What you probably don’t expect is something like Swildon’s hole, here in the Mendips.
The first citizens of Mars will be cave explorers.
So why don’t we want to live on the surface?
Here are two chocolate chip cookies that I’ve baked to go caving.
Out of the oven they were both the same temperature, but as you can see they’ve since started
to cool down.
The larger cookie has been able to retain more of its heat.
Inside it’s still gooey.
These cookies are just like Earth and Mars.
When the solar system formed they were both molten, but over the eons they’ve since
cooled down.
The much larger earth still has its gooey molten core, which gives us a protective magnetic
field.
Mars’s core cooled faster, just like the smaller cookie.
With no molten core to produce a magnetic field, Mars is defenceless against the nasties
of space.
Solar flares and galactic cosmic rays can pass through your spacesuit and permanently
damage cells and DNA.
In order to avoid this radiation, we need some form of shielding,
such as in the form of several metres of rock.
The best way to get that is to head underground, I’ll see you in a minute.
Since we took our first close up pictures of the planet in the 1960s, we’ve known that
Mars has a network of tunnels extending beneath the surface.
Unlike here in the Mendips these caves weren’t formed by water, but instead were carved out
by rivers of lava.
Fortunately, with the core freezing over, it is unlikely that we’re going to be roasted alive.
In order to make Mars our new home we just need to transform a small section of cave into living space
For that we need two things.
First we need to produce an atmosphere and then we need to
make sure this atmosphere doesn’t escape. Making an atmosphere isn’t super difficult.
Mars hasn’t had liquid water in millions of years, but around the equatorial regions
there are permanent deposits of ice.
That’s useful as a potential drinking supply, but with a little electricity we can make
something even better.
These two wires are connected to a DC power supply.
The are then submerged into this tank of water.
As you can see the electricity rips apart the water molecules into two constituent gasses.
The negative cathode is producing hydrogen gas and the positive anode oxygen.
As you can see, there is two times more hydrogen that oxygen, which makes sense given that
the chemical formula for water is H2O.
Its been about an hour and in that time, we’ve been able to produce three balloons of gas.
We’ll be able to use our oxygen gas to make a breathable atmosphere for our Mars explorers.
By combining our gasses back together we can produce something just as useful; rocket fuel.
All we need is a spark.
Keeping our new atmosphere in place is actually quite simple.
This is a limestone rock such as you would find in Swildon's hole. As you can see,
cracks along the surface make it easy for air to escape.
Fortunately our Martian caves don't have that problem.
Igneous rock is much more impervious, which means it will do a better
job at keeping in our atmosphere.
Because Mars’ caves were formed by lava, the insides already have an pretty good seal.
All we need to do is patch up a few gaps and put a big airlock at the enterance.
Colonising Mars from the inside out is our best chance at creating a new home for humanity.
But with whom are we going to share this new frontier?
Join us next episode as we descend further into the Caves of Mars.
Until then, this has been James Dingley from the Atomic Frotier. Keep Looking Up.