Lucy (spacecraft) facts for kids

Quick facts for kids
Lucy

Artist's conception of Lucy spacecraft flying past the Trojan asteroid 617 Patroclus and its binary companion Menoetius
Names	Discovery Mission 13
Mission type	Multiple-flyby of asteroids
Operator	NASA Goddard · SwRI
Mission duration	12 years (planned) 3 years, 8 months and 5 days (in progress)
Spacecraft properties
Manufacturer	Lockheed Martin
Launch mass	1,550 kg (3,420 lb)
Dry mass	821 kg (1,810 lb)
Dimensions	13 m (43 ft) in long Each solar panel: 7.3 m (24 ft) in diameter
Power	504 watts (furthest encounter)
Start of mission
Launch date	16 October 2021, 09:34 UTC
Rocket	Atlas V 401 (AV-096)
Launch site	Cape Canaveral SLC-41
Contractor	United Launch Alliance
Lucy mission patch Discovery Program ← InSight Psyche →

The Lucy mission is a NASA space probe on an exciting twelve-year journey. Its main goal is to visit eight different asteroids. These include two asteroids in the main Asteroid belt and six special asteroids called Jupiter trojans.

Jupiter Trojans are unique because they share Jupiter's orbit around the Sun. They travel either ahead of or behind the giant planet. Lucy will fly past each of these asteroids to study them up close. The entire Lucy mission costs about US$981 million.

In 2017, Lucy was chosen by NASA as part of its Discovery Program. It was selected along with another mission called Psyche.

The mission is named after the famous Lucy hominin fossils. Scientists hope that studying the Trojan asteroids will be like finding "fossils of planet formation." These asteroids are thought to be leftover materials from when planets and other bodies formed in our early Solar System. The original Lucy fossil was named after the 1967 Beatles song "Lucy in the Sky with Diamonds". The Lucy spacecraft even carries a special disc made of lab-grown diamonds for one of its instruments!

Exploring the Solar System with Lucy

Harold F. Levison, the main scientist for the Lucy mission.

The Lucy spacecraft launched from Cape Canaveral in Florida. This happened on October 16, 2021, at 9:34 AM UTC. It was launched using a powerful United Launch Alliance Atlas V rocket.

Lucy uses a clever trick called a gravity assist to speed up. It got its first gravity assist from Earth in October 2022. After flying past the asteroid 152830 Dinkinesh in 2023, it will get another boost from Earth in 2024.

In 2025, Lucy will fly by an asteroid named 52246 Donaldjohanson. This asteroid is in the inner main asteroid belt. It was named after the person who discovered the Lucy hominin fossil.

Then, in 2027, Lucy will reach the L₄ Trojan cloud. This group of asteroids orbits about 60 degrees ahead of Jupiter. Here, Lucy will fly past four Trojans: 3548 Eurybates (which has its own small moon), 15094 Polymele, 11351 Leucus, and 21900 Orus.

After these flybys, Lucy will return to Earth in 2031 for one more gravity assist. This will send it towards the L₅ Trojan cloud. This group of asteroids trails about 60 degrees behind Jupiter. In 2033, Lucy will visit a binary Trojan called 617 Patroclus and its companion, Menoetius.

The mission might end after visiting Patroclus–Menoetius. However, Lucy will then be in a stable orbit between the L4 and L5 clouds. This means the mission could be extended to explore even more asteroids!

Scientists believe Jupiter Trojans are very important. They are considered "dark" and reflect little sunlight. Jupiter is about five times farther from the Sun than Earth is. There might be as many Trojans as there are asteroids in the main asteroid belt.

How Lucy Was Developed

NASA chose Lucy through a special program called the Discovery Program. This program looks for new mission ideas. Lucy was one of 28 proposals submitted in 2015.

In 2015, Lucy was picked as one of five finalists. Each finalist received US$3 million to develop their ideas further. In January 2017, Lucy and the Psyche mission were officially chosen for development and launch.

In 2019, NASA announced that Lucy would launch in October 2021. The launch vehicle would be an Atlas V 401 rocket. The cost for this launch was about US$148.3 million.

By August 2020, Lucy was ready for its final assembly and testing. The spacecraft was transported to Florida in July 2021 for launch preparations. It was then placed inside the rocket's protective cover in September 2021.

Lucy successfully launched on October 16, 2021.

Lucys Scientific Tools

The Lucy spacecraft carries three main science instruments:

L'Ralph instrument.

• L'Ralph – This instrument is a camera that takes pictures in visible light and also measures infrared light. It helps scientists figure out what the asteroid surfaces are made of, like rocks, ice, or other materials. It's similar to an instrument on the New Horizons spacecraft.

CAD drawing of the L'LORRI.

• L'LORRI – This is a high-resolution camera that takes very detailed pictures. It will provide the clearest images of the Trojan asteroid surfaces. It's based on a camera used on the New Horizons mission.

L'TES instrument.

• L'TES – This instrument measures heat using infrared light. It helps scientists understand how hot or cold the asteroids are. This information can tell us about the materials and structure of the asteroid surfaces. It's similar to an instrument on the OSIRIS-REx mission.

• Radio Science – Lucys radio system will help measure the mass of the asteroids. It does this by detecting tiny changes in the spacecraft's radio signal as it flies past.
• T2CAM – This camera helps Lucy track the asteroids as it flies by. It takes wide-angle images to help scientists understand the asteroids' shapes.

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  Illustration of the deployed spacecraft

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  Lucy spacecraft solar arrays deploying and main engine burn

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  Instruments onboard

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  The Instrument Pointing Platform (IPP)

Golden Plaque on Board

A plaque on the Lucy mission featuring 20 messages from people on Earth.

The Lucy spacecraft carries a special golden plaque. This plaque shows the launch date, the positions of the planets, and maps of Earth's continents. It also includes 20 messages, poems, and song lyrics from famous people. These include Martin Luther King Jr., Carl Sagan, and The Beatles.

Since Lucy will stay in the Solar System and won't crash into a planet, there's a chance that people in the future might find it.

Lucys Asteroid Targets

Lucy will visit Jupiter's Greek (L4) and Trojan camps (L5) every six years.

Seven of the Lucy mission's targets: the binary asteroid Patroclus/Menoetius, Eurybates, Orus, Leucus, Polymele, and the main belt asteroid Donaldjohanson.

Here are the specific asteroids Lucy plans to fly by:

Lucys Journey in Space

Lucy spacecraft ready for launch.

Lucy being moved and attached to its rocket.

The launch of Lucy on October 16, 2021.

The Lucy spacecraft began its journey on October 16, 2021. It was launched by a United Launch Alliance Atlas V 401 rocket. The rocket first put Lucy into a low orbit around Earth.

About an hour later, the rocket's second stage fired again. This pushed Lucy onto its path towards the asteroids. The mission is planned to last twelve years. If the spacecraft is still working well, the mission might be extended to visit even more asteroids!

Solar Panel Issues

After launch, Lucy began to unfold its two large solar panels. These panels collect sunlight to power the spacecraft. One of the panels did not fully lock into its open position.

NASA engineers worked to understand and fix this issue. They found that the panel was mostly open, between 75% and 95% deployed. Even with this partial deployment, Lucy was still getting enough power for its mission.

In May 2022, the team tried to move the solar array further. This test helped them understand how the system worked in space. By August 2022, the solar array was between 353 and 357 degrees open. While not fully latched, it was stable enough for the mission to continue. The team decided to stop further attempts to fully latch the panel in December 2022.

Animation of Lucy's trajectory

Around the Sun
      21900 Orus

Around the Sun - frame rotating with Jupiter
      Jupiter

      Lucy ·       Sun ·       Earth ·       52246 Donaldjohanson ·       3548 Eurybates ·       617 Patroclus

See also

In Spanish: Lucy (sonda espacial) para niños

• DESTINY+, a planned Japanese mission to fly by multiple asteroids.
• Jupiter Icy Moons Explorer, a European mission to Jupiter's moons.
• OKEANOS, a proposed mission to Jupiter Trojans using a solar sail.