So what we're going to do is go through the various stages
that will be needed to make fuel on the Martian surface.
I've taken a tray full of ice, and covered it in sand to represent the Martian geology.
There's ice caps at the top and this is solid ice water.
And also solid carbon dioxide.
We can drill down to get this solid ice and turn it into liquid.
Take a screwdriver.
Heat it up.
Melt this ice.
By burrowing through this Martian surface that we've got here
we can turn frozen water into liquid water and steam.
Now we can use electricity to pull the hydrogen and the oxygen apart
by simply dropping a 9-volt battery into our bowl of water.
On the negative terminal, which is the fatter terminal, we see bubbles forming,
and that's hydrogen gas being formed out of the water.
Did Lewis and Clark cross the American continent bringing with them
all the food, water and air they would need for themselves and their horses
for a 3 year transcontinental trip of exploration?
No, if they had done that they would have needed a wagon train of supplies for every
man, and another wagon train for every horse, and then of course the wagon train men would
have needed more wagon trains and it would have gone exponential.
If you looked at these other mission plans, what you saw was that the majority of the
mass they were sending to Mars was the propellant to come back.
What is the travel-light and live-off-the-land approach to Mars exploration?
This is a little rocket ship for returning from Mars to Earth
in the terminal stage of the mission.
But no one is in it when it goes out the first time.
They have to be unfueled or this will weigh much to heavy to throw to Mars.
And then slung below the vehicle not shown in this diagram is a little truck in the back
of that truck is a little nuclear reactor.
You take the water you electrolize it, split it into hydrogen and oxygen, and you suck
in the Martian air, which is 95% carbon dioxide, and now you've got a fully fueled Earth Return
Vehicle sitting, waiting for you on the surface of Mars.
But it wouldn't be practical if you had to bring the fuel from Earth.
And in fact we make extra propellant beyond what the Earth Return Vehicle needs so we
can operate chemical powered vehicles on the surface of Mars for exploration purposes.
The ability to make use of local resources is not just the key to making the mission
cheap, it's also the key to making the mission effective.
Because there's no point going to Mars unless you can do something useful once you get there.
The Constellation program was the program NASA had started to put people back on the
Moon and I had been working on it for a number of years.
It was good that it got cancelled.
It was a program that was in really big trouble.
It was way over budget, it was poorly designed, it was being very poorly implemented.
But- I was where with a colleague and she did trajectory work like I did and I said-
Are you disappointed this has been cancelled?
I'll never forget what she said to me, she said-
Kirk, I've been here 30 years.
Every single thing I've ever worked on has been cancelled.
The old strategy, including the Constellation program,
was not fulfilling its promise in many ways.
That's not just my assessment.
And I think there is a parallel there, I think, between
what's going on in the nuclear industry and what's going on at NASA.
So it sounds like you each worked on a number of different reactors over your careers.
Everything I ever worked on got cancelled.
Not because of him though.
You know the Shuttle was a magnificent piece of technology development- In 1981.
Part of the problem was, U.S. held on to the Shuttle for 30 years.
And in 2011, the Shuttle was not such a magnificent technology development any more.
Because NASA kept holding on the old technology,
until finally President Bush had to say- We're going to stop doing it.
The Space Shuttle, after nearly 30 years of duty, will be retired from service.
I think there's a parallel there with the Light Water Reactor.
We build 100-some-odd Light Water Reactors
between the 70s and the 80s and a few into the 90s.
And, as you've seen from our visit to Oak Ridge,
there's talk about extending those reactors 60 and 80 years.
And you get into the same sort of argument of diminishing returns.
How long do you hold on to the old technology?
I don't see the trajectory as serving any purpose, because there are processing disadvantages,
there are engineering disadvantages, there are material science disadvantages.
All of those things are non-issues if you adopt a truly fluid fuel / cooling system.
Whether you're in space or on the Moon or on Mars.
You need something that is basically stupid-proof.
Right?
It's idiot-proof.
And all of the redundancy that is involved in solid fuel reactors is basically eliminated.
Desalinating briney water.
Synthesising liquid fuel.
Growing indoor crops.
These are how humans can reduce our ecological footprint here on Earth- and explore Mars
without breaking the bank.
In all environments, on Earth, and in zero gravity, we want reactors capable of producing
large amounts of power, yet are simple and compact.
On Earth, small reactors can be transported by train by truck or by ship.
Factory construction is much cheaper than on-site construction.
A small reactor also requires less natural resources to fabricate in the first place.
Size is even more important for off-world application,
because launching stuff into space is so incredibly expensive.
We don't want any complex mechanism for shuttling around solid fuel.
Much operational complexity takes place outside a nuclear reactor.
The enrichment of uranium.
The management of spent fuel.
Overall, Molten Salt Reactors are much simpler.
The greater efficiency enabled by liquid homogeneity means less mining, and less waste per kilowatt-hour
generated.
Unlike today's solid fuel reactors, which can only be economically fueled with uranium,
it is possible to fuel an appropriately designed Molten Salt Reactor economically with thorium.
Almost all of it will ultimately end up fissioning.
Out of about a thousand kilograms, about 15 kilograms of Plutonium-238 will be left over,
now this is good stuff.
Plutonium-238 is different than Plutonium-239, the stuff we use in bombs.
In fact it's worthless for bombs.
This is the stuff NASA uses in its deep-space batteries.
Voyager, Galileo, Cassini, New Horizons, all these deep space probes.
Almost everything that comes out of this reactor can be sold for product.
And then, it'll make enough Uranium-233 to replace itself with 1000 kg of thorium.
Breeding thorium requires a more complicated design than is required for a uranium fueled
Molten Salt Reactor.
The question becomes, do you only want the reactor to be as simple as possible?
Or- Do you want the entire fuel lifecycle to be as simple, and efficient, as possible?
In space, for most applications, we absolutely need our reactor to be as simple as possible.
A smaller, lighter reactor is of the utmost importance, for our immediate exploration
needs.
The first Molten Salt Reactor launched into space will undoubtedly be powered by Uranium
NOT Thorium.
But eventually, we want to maximize the efficiency with which we consume natural resources.
On Earth we do this because we don't like digging big holes over here, and dumping big
piles over there.
On the Moon and Mars, we might not worry about pollution, but we'd be far more constrained
in how we harvest natural resources.
Thorium is an element found everywhere.
It is junk.
Rare earth mining operations would just as soon pay you to take it off their hands.
If you're pulling out rare earths, and your deposit has- let's say- 8% rare earths, it
may have 14% thorium.
Every known way to extract rare earths from their mineral concentrates- thorium just literally
drops out like a rock and you have it.
The thorium is free.
So it's going to be the most valuable commodity in the world, with almost no value.
Because the element thorium can be isolated with basic chemistry, and because Molten Salt
Reactors do not require solid fuel fabrication, it is possible to mine dirt for energy even
on the Moon and on Mars.
One amazing application of Molten Salt Reactors is to solve the water problem.
I'm standing in Palo Alto, California, in Silicon Valley, and they are in the midst
of one of the worst droughts in California history.
Well, solve the water problem by reverse osmosis desalination of all that water we have off-shore
here-
Then make very environmentally friendly fertilizers- because you're doing zero-emission energy
source- and then solve the food problem.
And you can apply that model worldwide.
Any factory assembled advanced reactor, brought to market, could help make nuclear power safer
and less expensive.
But, it is Liquid Fueled Thorium Reactors which can completely decouple energy generation
from negative environmental impact.
LFTR consumes only the unwanted byproduct of existing mining operations.
There's so much rare earths that we're throwing away because of thorium.
One rare earth and usually one thorium atom.
We could solve the rare earth problem without opening any new mines and we can solve the
energy problem without mining either.
We need the thorium, and he needs someone to get rid of the thorium.
I realized that there was 60 people sitting on the other side of the podium going- Do
you think there's enough of it?
Do you think there's a stable supply?
How much thorium do you think you'll be pawing up a year?
And he goes- I think about 5000 tons.
He goes- Is that a lot?
By my calculations, 5000 tons of thorium would supply the planet with all of its energy for
a year.
I said- So your 1 mine, in Missouri, would bring up enough thorium- without even trying-
to power the entire planet.
And he goes- And there's like a zillion other places on earth that are just like my mine.
I mean- it's a nice mine, but it's not unique, it's not like this is the one place on earth
where this is found.
The promise of abundant clean energy has already been made by wind and solar advocates.
However, those are diffuse and intermittent sources of energy.
Thorium, when consumed in a molten salt reactor, is incredibly energy dense.
And thorium, in a molten salt reactor, can follow energy demand.
We did it at a number of different power levels.
You could change the load on this radiator by moving the doors down and the reactor would
follow the load.
As the salt would heat up, there would be less fissile material in the nuclear reactor
core, and so fission became less likely.
Conversely, as the salt cooled down, there was more material, because the salt was contracting,
and fission became more likely.
An inherently stable system.
In other words, gets hotter, cools down, gets too cool, heats up.
So that is a really amazing quality that a nuclear reactor can have and this reactor
had it in spades.
And then you have other things like wind and solar where you can't change the rate of what's
coming at all you just take whatever you're going to get.
We have to get beyond burning stuff for energy.
And we can go to a dispersed form of energy, which is gathering wind and solar.
Or we can go to a more concentrated form of energy, which is nuclear.
And the disadvantage of wind and solar that will always exist is the amount of labor,
energy, and expense of gathering and concentrating and directing that energy.
Because energy had to be collected and directed to do work.
And nuclear energy has already been collected.
Our national conversation on energy rarely mentions these concepts.
Energy density.
Energy reliability.
If we continue to ignore energy density and reliability,
we'll wind up in a future like this one-
A future where we continue to solve problems
through ingenuity and perseverance, but always with a disadvantage-
We won't be using energy to tackle problems, if we've constrained our own access to it.