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[Music]

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NASA's Lucy mission is heading
to the Jupiter Trojans,

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two swarms of asteroids trapped
in Jupiter's orbit.

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When it arrives,

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it will provide the first close-up
look at these primitive objects,

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thought to be fossils
from the dawn of the solar system.

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But to get there,
Lucy needs a little help from the Earth.

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[Music]

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After launching on October 16th, 2021,

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Lucy returned home exactly
one year later for the first of three

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Earth gravity assists, stealing
an undetectably small amount of Earth's

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orbital energy to boost the spacecraft.

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This allowed Lucy to skim
the inner edge of the main asteroid

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belt between Mars and Jupiter.
On November 1st, 2023,

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it flew by asteroid Dinkinesh

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and discovered a small moon,
which the mission named Selam.

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Now, Lucy is returning home once again
for another gravitational tug.

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On December 12th, at 1:20 p.m.

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Eastern Time, it will cross the Moon's
orbit from the direction of the Sun,

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greeted by a brilliant view of Australia
and the Pacific Ocean.

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In the hour before closest approach,
Lucy will begin to rotate, or slew,

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keeping the spacecraft stable as it skims
through Earth's upper atmosphere.

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Lucy will pick up speed
is it approaches the evening terminator,

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or boundary between day and night,
crossing into Earth's shadow.

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At 11:15 p.m., it will make its closest
approach to the planet,

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skimming about 220 miles above
the ocean west of California.

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Lucy will be traveling over
nine miles per second,

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allowing it to streak over North America
in only seven minutes.

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Just before midnight on the East Coast,
Lucy will slew back toward the Sun,

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catching a glimpse of sunrise over
central Africa.

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It will cross the Moon's orbit
about half a day later, bidding

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farewell to home until its third and final
gravity assist in December 2030.

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The 2024 encounter will boost

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Lucy's velocity by four-and-a-half miles
per second relative to the Sun,

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putting it on course for the L4 Trojans
that travel ahead of Jupiter.

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But first, Lucy will traverse the main
asteroid belt,

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making a flyby of asteroid
Donaldjohanson on April 20th, 2025.

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[Music]