Hi, I'm Neil deGrasse Tyson, your host for NOVA scienceNOW.
Forty years ago, humans landed on the moon.
We went back five more times,
but stayed only a few days each trip.
Many of us hope that someday we'll be able to stay longer,
establish a permanent base here,
maybe even use it as a rest stop for interplanetary travel.
But if that's going to fly,
the moon's got to give us a little help
by providing some basic resources.
One major resource NASA hopes to find any day now...
is water.
Who can deny it?
We all have a certain fascination with destruction.
Explosions, collisions-- they're an undeniable guilty pleasure.
And for a lucky few at NASA,
destruction is actually part of their job description.
PETER SCHULTZ: I blast things.
I've done this since I've been a kid.
That's exactly what I'm doing now.
I'm a grownup and I still play in the sandbox.
I get to throw things at very high velocity.
TYSON: This is Peter Schultz's playground:
the "vertical gun range" at NASA's Ames Research Center
in northern California.
For more than 30 years,
Schultz and his team have been loading projectiles
into this 30-foot steel barrel mounted on a lifting arm.
They then fire them into small models of planetary surfaces.
So this is the gun, huh?
Yeah, this is the big gun.
But it looks like a contraption,
like something out of Jules Verne.
It was made in the '60s.
So this is... this is at the birth of Apollo.
This is when... this is the type of gun that they made
to try to understand the moon.
The surface of the moon?
The surface of the moon.
TYSON: Getting to the moon-- and colonizing it--
have always been targets of human obsession.
But it was 1969 before we really started
to understand the moon first-hand.
NEIL ARMSTRONG: I'm going to step off the landing.
That's one small step for man, one giant leap for mankind.
TYSON: Exciting as that first step was, the moon looked pretty bleak.
In the nearly 50 pounds of rocks brought back
by Armstrong, Aldrin and Collins,
scientists found hardly any ingredients--
like nitrogen, hydrogen and carbon dioxide--
that are essential to support human life.
And without the most important of them-- water--
the moon would forever remain hostile to human colonization.
Lunar scientists had long theorized
that large stores of water might have accumulated on the moon
just as they did on earth--
deposited by the impacts of comets.
But they believed any water near the surface exposed to the sun
would have long since evaporated.
In 1998, NASA launched Lunar Prospector,
a small spacecraft designed to orbit the moon pole-to-pole.
It carried a highly sensitive spectrometer--
a device tuned to detect hydrogen,
a possible sign of water--
to a depth of three feet, even in areas of permanent darkness.
And in the darkest craters near the moon's poles,
Prospector struck the mother lode: signs of water--
up to six billion tons of the stuff.
This hint of water changed the game in an instant.
Water makes up sort of the foundational building blocks
for living on the land on the moon.
A half-liter bottle of water on average might cost $15,000
to bring it to the moon.
That's crazy.
What if the water was there?
You could be using it to create fuel
and use the moon as a launching point to go to other places.
TYSON: So for NASA, finding water on the moon
may in fact be the next big step toward space colonization.
But before we can think about living up there,
we have to make sure we know where the water is.
And NASA has a new mission aimed at doing just that.
So this is LCROSS?
MAN: This is LCROSS.
TYSON: Meet LCROSS,
NASA's next big step in the hunt for lunar water.
It looks like this ring, right,
with just these things stuck on it.
It actually looks like a sewer pipe.
(laughs)
TYSON: Short for
"lunar crater observation and sensing satellite,"
LCROSS is a small and simple spacecraft,
designed to sit on top of the upper stage
of its launch rocket
and take control of the rocket when it's empty.
LCROSS's purpose is to smash
that school-bus-sized empty rocket stage
into a dark lunar crater at 5,600 miles an hour.
The impact will toss the crater's contents
high up into the sunlight, where LCROSS can analyze them
in great detail and perhaps find new evidence of lunar water.
Remember Pete Schultz's vertical gun?
Well, its purpose is to prepare NASA to experience on Earth
what LCROSS will encounter on its moon mission.
To do that, Schultz's team loads a projectile
that will act as a stand-in for the empty rocket stage
that LCROSS will throw at the moon.
Then they stand back and watch what happens inside the chamber.
So, we're about to go in here,
but tell me first, the gun's not loaded.
Let me check.
(laughing)
Let me first get this...
High-tech smoothing device.
TYSON: Inside the chamber,
which will later be drained of air
to mimic the moon's lack of atmosphere,
Schultz prepares his own little mini-diorama
of the lunar surface
using an array of highly specialized gear.
So this is not the surface of the moon,
because it's smooth.
That's right, so now we have to make some craters, so...
That's the fun part. Yup, that's right.
TYSON: The whole idea here is to re-create the situation
that LCROSS will observe when it flies through the dust plume
created by the impact of its empty rocket stage.
It takes about 20 minutes to suck the air out of the chamber.
The tension builds.
Then comes the moment of...
(record scratching sound)
Well, silence.
Hey, there's no sound in a vacuum, all right?
But the results are still impressive.
SCHULTZ: Look at this... see this?
That's the red stuff, and now that's coming into light.
TYSON: Into sunlight?
Into sunlight and you're seeing the ejecta.
The red stuff is glowing red hot.
TYSON: When the simulation is slowed down,
the beauty and complexity of the plume become apparent.
It won't just be a big pile of moon dirt;
it'll be a delicate trumpet- shaped curtain of lunar dust
spreading out from the center of the impact site.
It is beautiful, but how will NASA be able to tell
what it's made of and if there's water to be found?
This is the spot, huh? This is it.
TYSON: In this makeshift lab,
team members are using some inexpensive drug-store supplies
to test what LCROSS will see when it analyzes
the impact's dust curtain.
The lunar dust is quite fine,
like baby powder,
so it's not too far an analog.
Wait, wait, wait, what's this thing?
That's a vibrator.
I've seen these.
This feels good.
It does feel good.
TYSON: As the baby powder is shaken through the sieve,
the team tests how the sun's light will be reflected
and scattered when it passes through the dust
to LCROSS's optical spectrometers.
So what you're really doing is exploiting the fact
that the sunlight is coming through the dust
in order to analyze the dust itself.
That's right.
TYSON: As sunlight passes through the dust curtain,
the compounds in the dust
absorb specific frequencies of light.
LCROSS's optical spectrometers measure
which frequencies are absorbed, and from those measurements,
scientists can tell exactly what the dust is made of.
If LCROSS is lucky, it will see a telltale signature like this,
indicating...
Water.
That's why we're going.
ANDREWS: We want to move from just sorties
to longer stays to habitation.
Next, instead of throwing away Launthe empty second stage,oç
tiny LCROSS held onto it.
This will be its projectile.
Then, LCROSS began shepherding this empty space junk
in two huge orbits out past the moon
and all the way back around the Earth.
This slingshot trajectory is required
to get LCROSS and its projectile up to speed
and lined up perfectly with the target crater
near the moon's north pole.
Then comes the final, delicate dance.
COLAPRETE: Eight hours prior to impact,
we let go of that upper stage of the rocket, the Centaur,
and we watch it as it goes in and impacts.
When it impacts, it makes an explosion.
Our little shepherding spacecraft
now becomes an observing spacecraft.
Eventually we actually fly through the plume itself,
making measurements the whole time, and impact ourselves.
about two-and-a-half months after launch,
LCROSS will meet its demise.
And if it does hit its mark,
the resulting 40-mile-high debris plume should be visible
from Earth through an amateur telescope.
And in one fleeting instant,
the LCROSS team will know success or failure.
But on a grander scale, much more is at stake.
If LCROSS does find water,
we may just be looking at the first rest stop
on our way to the stars.