Original subtitles

♪ I was strolling on the moon one day ♪

♪ In a merry, merry month of December, no May ♪

♪ When much to my surprise, a pair of moony eyes ♪

Jack Schmitt's career as a singer

was never destined to go very far.

But his career as a geologist took him further

than any scientist before him.

Schmitt was the first, and still is the only scientist,

to set foot on the moon.

During their extensive moonwalks in December 1972,

Jack Schmitt and Gene Cernan collected

a treasure trove of rock samples that would keep

geologists back on Earth busy for years.

But the answer to one question eluded them.

Would they find evidence of water in the lunar dust?

Because if they did, we could split it

into its component elements to make the most

powerful rocket fuel known to man.

And our moon would become an invaluable gas station

in the sky for future spacefarers.

(intense music)

In the late 1950's, and early 1960's,

orbiters and landers from both the United States

and the Soviet Union

became regular visitors to the moon.

Surveying the surface, and sampling the lunar landscape.

From 1969 to 1972, the Apollo program managed to place

12 humans on the moon and bring them back alive.

Together, they returned to Earth

with a total of 382 kilograms.

That's almost half a ton, of moonrock.

But even given all this activity,

most of the surface of the moon remained unexplored.

And what was learned from those brief forays across

the magnificent desolation of the moon, was limited.

We've landed in six spots.

All those six spots were within 25 degrees of the equator.

And we learned quite a bit about the moon.

We learned what its basic chemical composition is,

we learned how it works,

what geological processes have shaped it

what its history is,

what its evolution has been over the past

four and a half billion years.

So we have a pretty good understanding of that.

And we made a rather startling

discovery in the last 20 years,

that we don't know everything that we thought we did.

That the poles are a unique environment.

And the reason they're unique is because of the way

the moon's spin axis is oriented.

The Earth's axis of rotation

is significantly tilted in relation to the plane

of its orbit around the sun.

A full 23.4 degrees.

That's what gives us our seasons,

and it's why, when it's summer in the northern hemisphere,

it's winter in the south.

But the moon's axis of rotation is hardly tilted at all,

with respect to its plane around the sun.

A skimpy 1.5 degrees.

And that creates some rather unique

conditions at the moon's poles.

What that means is, if I'm an observer

standing at the pole,

I always see the sun at or near the horizon.

Now if I'm on a peak, I will actually stick up into

the sunlight, I'll see the sun all the time.

But conversely if I'm in a hole, I'll never see the sun.

So that simple relation of the spin axis

and the sun is responsible for creating

a unique environment at the poles.

The areas that are in permanent

darkness are extremely cold.

If any kind of water molecule gets into them,

it can never get out again.

There's no known process to remove it.

Then the moon is bombarded by water bearing objects,

and has been for its entire history.

There's water in commentary cores,

there's water in meteorite minerals,

there's water in interplanetary dust.

So those water and hydrogen bearing species

hit the moon constantly.

And most of that's lost to space.

But the stuff that hits the moon and finds

its way into a cold trap, is trapped.

That's why they're called cold traps.

And so the thought was, well, maybe there's an

appreciable amount of water ice in these craters.

And we didn't really know.

And all of the Apollo missions were sent

in equatorial orbit so we didn't have

the instruments needed to look into those

dark areas and see what was there.

So it wasn't until 20 years after Apollo,

in 1994, the Clementine mission orbited the moon

for 71 days and mapped the moon globally.

And we improvised an experiment with Clementine.

Used radio waves to bounce them off the floors

of the dark craters and look for ice.

And we finally concluded that we did see evidence

for ice reflection in the radio waves sent by Clementine.

Now that set off a 20 year set of missions

from a variety of countries.

There was a lunar prospector mission

that NASA sent in 1998,

there was the SMART-1 mission in the early

2000's sent by the European space agency,

the Japanese sent Kaguya, lunar orbiter,

the Chinese have had two lunar orbiters,

India sent an orbiter, Chandrayaan-1,

and the Americans sent the lunar reconnaissance orbiter.

All of them carried a varitey of instruments using different

techniques to look and map the dark areas of the moon.

All of them found evidence for substantial

quantities of water there.

We finally proved it, without a doubt,

through the impact of something called the LCROSS.

And it was the upper stage of a rocket

that was slammed into the moon.

And then we looked at the ejecta thrown

out by the impact of that rocket.

And what we found was that water vapor and water

ice particles were thrown out by that impact.

The amount of water turned out to be

between five and 10% of

the total amount of ejecta.

Doesn't sound like a lot, but that actually is quite a bit,

considering that most people thought the moon

had virtually no water at all.

So we know that there's water there,

what we don't know is what its detailed properties are.

And that's what we need to find out before we go back.

The presence of plentiful,

accessible water on the moon

may be the single most important unanswered question

underpinning any decision to return.

Such major questions, and there are many

in the realm of space science,

are known as strategic knowledge gaps.

There are two aspects to understanding

the SKG's, the strategic knowledge gaps.

You want to know how the ice is distributed,

and what its configuration is and its physical properties,

because you want to know where it came from.

You want to know its origin,

you want to know it's evolution,

you want to know the geologic scientific

story behind the water.

The other aspect of it is the utilitarian value of it.

I want to harvest that water,

I want to use that water for a variety

of different useful products.

But before I can do that, I need to know where it is,

I need to know what its physical state is,

I need to know how to get to it,

and I need to devise a technique that allows

me to extract it from where it is.

So the strategic knowledge gaps reflect our ignorance,

they reflect the amount of things that we don't know

about the ice that we need to know before we can

actually start using it for practical purposes.

It's like mining on Earth.

Step one is prospecting.

You take aerial photos,

you look at pictures from satellites,

and you look for regions of interest.

That looks really interesting,

I'm gonna to go send a prospector there.

And that person's gonna go and he's gonna

pick up rocks and take samples.

So step one really is doing that.

And then from that point, we'll hopefully be able

to set up some kind of a mining operation.

Here again starting out small.

We're not gonna churn out commercial

quantities of these things.

We have to test our techniques.

Verify all the operations.

Let it run for a period of time, see if it breaks.

If it breaks, I learned something.

What kind of maintenance do I need?

From that I can build a business case.

Okay, now I know where the resource is,

I know how difficult or how easy it is to extract,

I've demonstrated these things.

Now can I scale it up?

And so over time, that's kinda what I hope to see.

Is, we do this first step, prospect.

If it identifies economically

viable quantities of water,

then that will trigger a new space race,

that some observers are calling the next Gold Rush.