WEBVTT FILE

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About 150 million years ago, Earth's

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most recent supercontinent
was in the process of breaking up.

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Sauropods dominated the lush, slowly
separating landmass

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that would become today's
familiar continents.

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Meanwhile, in the asteroid belt,

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a breakup of a different sort
was taking place.

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The large asteroid 163
Erigone was pummeled in a collision,

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shedding debris
to form a new family of asteroids.

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Fast forward to 3.2 million years ago,
long after the fall of the dinosaurs,

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when an early hominin walked upright
through an Ethiopian river valley.

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Now, a robotic explorer
named for our most famous

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human ancestor is heading to a member
of the Erigone asteroid family

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en route to the fossils of
planetary formation.

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[Music]

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Launch audio and commentary:
“Liftoff! Atlas V takes flight.”

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NASA's Lucy mission launched
in October 2021

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and flew past Earth in 2022
and 2024 for a pair of gravity assists.

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In early 2025, Lucy entered the
main asteroid belt,

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on course for humanity's
first encounter with

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52246 Donaldjohanson.

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The asteroid was named in honor
of the paleoanthropologist

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who discovered the Lucy fossil in 1974,
rewriting the textbooks on human origins.

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While asteroid Donaldjohanson has
never been seen up close,

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its brighrtness varies greatly
as it rotates,

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suggesting an elongated shape.

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It is a member of the Erigone
family of asteroids,

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made from fragments of the collision

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that took place
about 150 million years ago.

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Earth-based observations
suggest that Donaldjohanson is

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carobn-rich, has an average diameter
of about four kilometers,

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and spins on its axis extremely slowly,

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giving it a 251-hour day.

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On Sunday, April 20th, Lucy will approach
Donaldjohanson from the direction

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of the Sun, traveling 13.4km per second
relative to the asteroid.

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As its target grows near,
the spacecraft will slowly rotate,

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keeping the asteroid in view.

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Over the course of a few hours,
Donaldjohanson will transform

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from a point of light into a
detailed world.

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Lucy's Long-Range Reconnaissance Imager
will capture high-resolution pictures

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throughout the flyby, providing our best
look yet at the asteroid.

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Just before closest approach,

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when Lucy is about 900km from its target,
it will abruptly turn its Instrument

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Pointing Platform away from the Sun
to protect its sensitive electronics.

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Shortly after the flyby,
Lucy will perform a “pitchback” maneuver,

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changing the direction of its rotation to
turn its high-gain-antenna toward Earth.

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Two hours later, data from Lucy
will deliver the first close-up views

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of Donaldjohanson, a surviving remnant
of the solar system's chaotic past.

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Following the flyby,

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Lucy will continue to pass
through the main asteroid belt.

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In August 2027, it will reach Eurybates,
an asteroid more than ten times

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larger than Donaldjohanson
and a member of the Jupiter Trojans.

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These primordial and primitive
objects are trapped

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in Jupiter’s orbit, and
are considered the “fossils” of

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planetary formation.

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Between 2027 and 2033, Lucy
will make five separate

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encounters with Trojan asteroids
and their moons.

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It will become the first spacecraft
to explore this

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ancient population...

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asteroids more than one thousand
times older

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than our most famous human
ancestor...

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formed at the dawn of the
solar system,

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long before dinosaurs
ruled the Earth.

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[Music]