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♪

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If you want to drive a rover on
Mars, you have to keep in mind

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there's no gas station
for millions of miles

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and there's no outlet
to plug into for power.

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That's why NASA's
Curiosity rover on Mars

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--and other NASA spacecraft
that explore the solar system--

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use something called
"radioisotope power."

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A radioactive substance
releases heat

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as it breaks down or decays.

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A system that converts that
heat into electricity is called

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a radioisotope power system.

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These systems get fancy names.

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Curiosity's power system
is called an "MMRTG":

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multi-mission radioisotope
thermoelectric generator.

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MMRTGs are reliable
and last a long time.

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NASA's Jet Propulsion
Laboratory is working with

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the Department of Energy
on ways to make them

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even more powerful and capable.

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So researchers want to
make the next generation

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of radioisotope
power systems,

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the eMMRTG.

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The "e" stands for "enhanced."

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The new thermoelectric
technology in development is

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based upon materials
called skutterudites.

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They are a part of a
family of compounds

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with many heavy atoms
and complex structures.

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Skutterudites conduct
electricity like a metal but

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insulate against heat
the way glass does.

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At the same time
they can generate

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sizable electrical voltages,

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just what engineers need to
convert heat into electricity.

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Engineers use this material in
devices called thermocouples,

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which are used to
generate electricity.

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One of the thermocouple's
shoes is hot and one is cold.

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This heat, transferred across
a big temperature difference,

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makes electrical charges flow

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from the hot shoe
to the cold shoe

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and produces an
electrical voltage.

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And this generates
useful electrical power.

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If these materials were put
in the same kind of generator

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that's on the Curiosity rover,

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with some small tweaks,

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the generator could be up
to 25% more efficient.

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After 17 years a spacecraft
could have 50% more power

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than with the current design.

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That means a spacecraft with
an eMMRTG could fly longer

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and do more science
during its lifetime.

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This kind of research
could help us on Earth, too.

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For example, some of the
heat that gets wasted

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when you drive your car could be
reused and put back into the car

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to charge the battery
or power electronics.

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JPL is collaborating with

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leading U.S. materials
scientists to design and study

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even more advanced

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high-temperature
thermoelectric materials.

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The next time you need to
replace your car battery,

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think about how
NASA's spacecraft

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can't replace their batteries.

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But as we improve
radioisotope power systems,

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they can go for longer and
longer--powered by heat,