Lucy

Lucy mission, animated monthly from Launch through June 2025 (completed) (Large File: 9.9 MB): The first mage above shows Lucy just before its flyby with asteroid Dinkinesh on November 1, 2023. 

Lucy mission, animated monthly from Launch through November 2028 (completed and future) (Very Large File: 35.8 MB): The second image above Lucy just after its flyby with Orus on November 11, 2028.

Lucy mission, animated monthly from February 2026 through mission end in March 2033 (future) (Very Large File: 39.5 MB): The third image above shows Lucy just after its flyby of Patroclus on March 3, 2033. This is the mission's end as currently planned. 

Lucy mission, animated monthly from June 2025 through February 2029 (future) (Large File: 7.8 MB)

Lucy mission, animated monthly from February 2029 through March 2033 (future) (Large File: 8.7 MB)

NASA's Lucy mission is a robotic space probe designed to study the Jupiter Trojan asteroids. These asteroids orbit the Sun in two large "swarms" that lead and trail Jupiter, at the same distance from the Sun as the gas giant. Scientists believe the Trojans are remnants of the primordial material that formed the outer planets, essentially "time capsules" from the early solar system. Studying them can provide vital clues to understanding the formation and evolution of our solar system and potentially even the origins of life on Earth.

Key objectives of the Lucy mission include:

• Understanding the early phases, conditions, and processes of solar system formation.

• Determining the composition, structure, and geology of Trojan asteroids.

• Investigating the possibility of changing orbits of the giant gas planets.

• Looking for rings and satellites of the Trojan asteroids.

The Lucy spacecraft launched on October 16, 2021, and is on a 12-year journey to explore a record-breaking number of asteroids. While its primary targets are the Jupiter Trojans, Lucy also makes flybys of main belt asteroids, like Dinkinesh, to test its instruments and trajectory.

The flyby of Dinkinesh on November 1, 2023, was an engineering test of Lucy's autonomous tracking system, which is crucial for precisely targeting its main scientific objectives. This successful encounter demonstrated Lucy's capabilities and delivered the unexpected discovery of Selam, adding to our understanding of asteroid systems.

Lucy will continue its journey, performing gravity assists from Earth to adjust its trajectory, and is scheduled to begin its primary mission of exploring the Trojan asteroids in 2027.

The Lucy mission has a packed schedule of flybys and encounters, primarily focused on the Jupiter Trojan asteroids, with some crucial main belt asteroid flybys along the way to test its systems and gather additional scientific data.

Flybys

Here's a list of the main flybys and encounters during the Lucy mission, including those that have already occurred and those planned for the future:

Past Encounters:

• October 16, 2021: Launch from Cape Canaveral, Florida.

• October 16, 2022: First Earth gravity assist (Earth flyby). This was a crucial maneuver to help Lucy gain speed and adjust its trajectory.

• November 1, 2023: Flyby of (152830) Dinkinesh (main belt asteroid) and its newly discovered satellite Selam (a contact binary). This was an engineering test of Lucy's autonomous tracking system.

• December 12, 2024: Second Earth gravity assist (Earth flyby). This will send Lucy out towards the Trojan asteroids.

• April 20, 2025: Flyby of (52246) Donaldjohanson (main belt asteroid). This served as a dress rehearsal for the Trojan asteroid encounters.

Upcoming Planned Encounters:

• August 12, 2027: Flyby of (3548) Eurybates (Trojan asteroid, Greek camp) and its satellite Queta.

• September 15, 2027: Flyby of (15094) Polymele (Trojan asteroid, Greek camp) and its unnamed satellite.

• April 18, 2028: Flyby of (11351) Leucus (Trojan asteroid, Greek camp).

• November 11, 2028: Flyby of (21900) Orus (Trojan asteroid, Greek camp).

• December 25, 2030: Third and final Earth gravity assist (Earth flyby). This will send Lucy to the second swarm of Trojan asteroids.

• March 3, 2033: Flyby of the binary pair (617) Patroclus and Menoetius (Trojan asteroids, Trojan camp).

Asteroid Dinkinesh

(152830) Dinkinesh is a small asteroid located in the inner main asteroid belt between Mars and Jupiter. Its name means "you are wonderful" in Amharic, an Ethiopian language, and was given in honor of the Lucy fossil, for which the Lucy mission is also named.

Dinkinesh is approximately 790 meters (0.5 miles) at its widest. A surprising discovery made by the Lucy spacecraft during its flyby was that Dinkinesh is not alone; it has a natural satellite named Selam. Even more remarkably, Selam itself is a contact binary, meaning it is composed of two smaller objects (each about 220 meters, or 0.15 miles, in diameter) touching each other. This was the first time a contact binary had been observed orbiting another asteroid.

Observations of Dinkinesh and Selam have revealed a complex history. Dinkinesh has a prominent equatorial ridge and a linear trough, suggesting it has some internal strength and may have undergone a sudden "break-up" event where a chunk shifted, forming debris that later coalesced to create Selam. The system is tidally locked, with Selam orbiting Dinkinesh every 52.7 hours.

Dinkinesh is also notable for being the smallest main belt asteroid ever visited by a spacecraft, providing valuable insights into how asteroids evolve, especially those that might eventually leave the main belt and become near-Earth asteroids.

Trojan Asteroids

The Lucy mission is designed to visit a record number of asteroids, providing unprecedented insights into the early solar system.

The terms "Greek camp" and "Trojan camp" refer to the two distinct groups of Jupiter Trojan asteroids. These asteroids share Jupiter's orbit around the Sun, but they don't actually orbit Jupiter itself. Instead, they are trapped in gravitationally stable regions known as Lagrange points.

Here's a breakdown:

Lagrange Points (specifically L4 and L5): For any two large celestial bodies orbiting each other (like the Sun and Jupiter), there are five special points in space where a third, much smaller object can maintain a relatively stable position. These are called Lagrange points, named after the mathematician Joseph-Louis Lagrange.

• • L4: This point is located 60 degrees ahead of the larger planet (Jupiter in this case) in its orbit around the Sun, forming an equilateral triangle with the Sun and Jupiter.

  • L5: This point is located 60 degrees behind the larger planet (Jupiter) in its orbit around the Sun, also forming an equilateral triangle.

• The "Camps" and Naming Convention:

  • Greek Camp (L4): The cluster of Trojan asteroids at the L4 Lagrange point (leading Jupiter) is known as the "Greek camp." By convention, asteroids in this group are named after Greek heroes from the Trojan War (e.g., Achilles, Agamemnon, Odysseus).

  • Trojan Camp (L5): The cluster of Trojan asteroids at the L5 Lagrange point (trailing Jupiter) is known as the "Trojan camp." Asteroids in this group are named after Trojan heroes from the Trojan War (e.g., Hector, Aeneas, Priam).

• There are a couple of notable exceptions to this naming convention, as some asteroids were named before the rule was firmly established:

  • (624) Hektor is a Trojan (from the Trojan side) but is located in the Greek camp (L4).

  • (617) Patroclus is a Greek (from the Greek side) but is located in the Trojan camp (L5).

Why are they important?

The Jupiter Trojans are considered "fossils" of the early solar system. Scientists believe they are remnants of the primordial material that formed the outer planets, having been captured in these stable Lagrange points billions of years ago. By studying their composition, geology, and dynamics, the Lucy mission aims to:

• Understand the conditions and processes of solar system formation.

• Gain insights into how the giant planets, particularly Jupiter, migrated and evolved.

• Potentially shed light on the origins of water and organic materials on Earth.

So, the "Greek camp" and "Trojan camp" are simply the two major populations of these fascinating, ancient asteroids that Lucy is designed to explore.