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NASA Lucy Probe

Lockheed Martin · Jupiter Trojan Asteroid Flyby Science Probe · USA · Digital Age (2010–present)

NASA Lucy Probe — Jupiter Trojan Asteroid Flyby Science Probe
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The Lucy is an American Lagrange-point small-body flyby spacecraft — Lockheed Martin's NASA Discovery Program mission to visit Jupiter's Lagrange-point co-orbital bodies. Lockheed Martin developed Lucy at the Denver / Waterton facility in 2017-2021; launched on an Atlas V 401 from Cape Canaveral on 16 October 2021. Lucy is on a 12-year mission to fly past 8 different small bodies — 1 main-belt asteroid + 7 co-orbital objects in Jupiter's L4 + L5 Lagrange points. The mission will provide humanity's first close look at these co-orbital bodies, which preserve material from the outer solar system's early formation period.

Lucy is a roughly hexagonal spacecraft with two large circular solar arrays (7.3 m diameter each — among the largest deep-space solar arrays ever flown). Dry mass 821 kg, launch mass 1,550 kg. Solar arrays generate ~18 kW at Earth + ~500 W at Jupiter's distance. Instruments: L'Ralph (visible-IR imager), L'LORRI (long-range imager — derived from New Horizons' LORRI), L'TES (thermal-emission spectrometer). The spacecraft is named after the Australopithecus afarensis fossil 'Lucy' — both the spacecraft + the fossil are intended to reveal early-origin material (early hominid for the fossil; early solar-system planetesimals for the spacecraft).

Lucy's first asteroid encounter was main-belt body 152830 Dinkinesh on 1 November 2023 — a surprise discovery during the flyby was that Dinkinesh has a small moon (a binary system), making the encounter scientifically rich. The principal Trojan encounters begin in April 2025 with the Trojan Eurybates (a Greek-camp Trojan). The full mission visits 4 L4 Greek-camp objects (Eurybates, Polymele, Leucus, Orus) 2025-2028 + 2 L5 co-orbital bodies (Patroclus + Menoetius) in 2033. The spacecraft will continue indefinitely after 2033 in a permanent orbit between L4 + L5. Lucy will visit more independent solar-system bodies than any previous mission.

For Kids — a shorter, friendlier version

Lucy is a spacecraft built by Lockheed Martin for NASA. It launched on October 16, 2021, from Cape Canaveral in Florida. Its mission is to visit 8 different asteroids over 12 years. These asteroids orbit near Jupiter, very far from Earth.

The asteroids Lucy will visit are called Trojan asteroids. They have been around since the solar system first formed. Scientists think studying them will teach us about how planets were made long ago. No spacecraft has ever visited these asteroids before.

Lucy has two huge round solar panels to power it in space. Each panel is wider than a school bus is long! They collect sunlight to make electricity for the spacecraft. Near Jupiter, they still make enough power to keep Lucy working.

The spacecraft carries special cameras and sensors. One camera can see objects from very far away. Another tool measures heat coming from the asteroids. Together, they help scientists learn what the asteroids are made of.

Lucy is named after a very old fossil of an early human ancestor. That fossil was also called Lucy. Just like the fossil taught us about early humans, the spacecraft Lucy will teach us about the early solar system.

Fun Facts

  • Lucy will fly past 8 different asteroids on its 12-year journey through space.
  • Each of Lucy's two solar panels is wider than a school bus is long.
  • Lucy was built at a Lockheed Martin facility in Denver between 2017 and 2021.
  • The Trojan asteroids Lucy will visit share an orbit with the giant planet Jupiter.
  • Lucy's solar arrays are among the largest deep-space solar arrays ever flown.
  • The spacecraft is named after a famous ancient fossil of an early human ancestor.
  • Lucy weighed about 1,550 kg at launch — heavier than a compact car.
  • No spacecraft has ever visited Jupiter's Trojan asteroids before Lucy.

Kids’ Questions

Why is the spacecraft called Lucy?

It is named after a famous old fossil called Lucy. That fossil was from an early human ancestor. Scientists thought the name was perfect because both Lucys help us learn about ancient origins.

How does Lucy get power so far from the Sun?

Lucy uses two giant round solar panels to collect sunlight. Even far away near Jupiter, they can still make enough power. Each panel is wider than a school bus is long!

What will Lucy do when it reaches an asteroid?

Lucy will fly close past each asteroid and take pictures. Its cameras and sensors will study what the asteroids look like and what they are made of. This will help scientists learn how the solar system formed long ago.

How long will Lucy's mission last?

Lucy's mission lasts 12 years in total. It launched in 2021 and will visit asteroids all the way until 2033. That is a very long trip through our solar system!

Variants

Lucy (single mission)
Unique spacecraft. 8-asteroid mission 2021-2033.

Notable Operators

NASA Discovery Program (2021-present)
Sole operator. Southwest Research Institute mission management.

Frequently Asked Questions

Why are Trojan asteroids scientifically valuable?

The These co-orbital asteroids orbit at Jupiter's L4 + L5 Lagrange points — gravitationally-stable regions 60° ahead of + behind Jupiter in its orbit around the Sun. They are believed to have been captured from the outer solar system early in the planet-formation period (~4.5 billion years ago) + have been gravitationally protected from subsequent disruption ever since. Their compositions thus preserve the original outer-solar-system planetesimal material — possibly material from the Kuiper Belt or further. Studying their colours, surface compositions, + morphologies should constrain models of solar-system formation + early planet-migration. Until Lucy, no spacecraft had ever observed a Trojan up close — all knowledge came from telescopic observations.

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