Why Is NASA Launching A Robotic Archaeologist Named Lucy?

NASA is scheduled to launch a survey of asteroid clusters along Jupiter’s orbital path on Saturday. They are known as Trojan swarms and represent the last unexplored regions of asteroids in the solar system. The spacecraft, a deep space robotic archaeologist named Lucy, will attempt to answer pressing questions about the origins of the solar system, how the planets migrated to their current orbits, and how life arose on Earth.

“We’ve never gone this far to study asteroids,” said NASA administrator Bill Nelson. “By doing so, we will be able to better understand the formation of the solar system, better understand ourselves and our evolution.”

After a six-year journey, Lucy will fly close to seven Trojan asteroids by 2033, completing wild laps of the sun that, in some graphic visuals, outline the Formula 1 racetrack.

The spacecraft will study the geology, composition, density and structure of Trojans, which are small bodies locked in fixed points along Jupiter’s solar orbit, fixed in their orbits in front of or behind the massive planet.

“It’s always interesting to go somewhere for the first time,” said Cathy Olkin, assistant principal investigator for the Lucy mission. “Each time we do this, we learn more about our solar system and the field of space we live in.”

Humanity has explored various small rocky bodies throughout the solar system. NS NEAR mission landed on Eros in the inner asteroid belt. NS Dawn mission orbits Ceres and Vesta, the two largest worlds in the belt between Mars and Jupiter. of japan Hayabusa missions and NASA’s OSIRIS-REX Completed close encounters with near-Earth asteroids. And New Horizons mission visits Arrokoth, an object inside the distant Kuiper belt of the solar system.

However, Trojans around Jupiter have not yet been explored. About 10,000 such objects have been discovered. When the first was spotted more than a century ago, astronomers began naming them after the heroes of Homer’s Iliad. The result was the generic identifier of the “Trojan”.

The mission name “Lucy” is a reference to the 3.2-million-year-old australopithecine skeleton discovered in 1974 that revealed the secrets of human evolution. The NASA team hopes the robotic Lucy will do the same for the evolution of the solar system, and prehistory is a recurring theme among mission scientists.

Tom Statler, a Lucy program scientist at NASA, describes Lucy as “planetary archaeology” and compares it to the study of the pyramids in Egypt.

Dr. “If you want to understand how the pyramids were built, you can go and look outside, you can climb all over them,” Statler said. But doing so will give little answer about how they were actually built.

“But if you can find and dig up the abandoned construction site next to the pyramids and find the tools and leftover blocks used to build them – things that are broken and formed but not used – then you start to understand the inside of a pyramid and how it got there,” he explained.

“This is what we do with asteroids,” he said. “We’re digging up what’s left of the construction site.”

The mission was born out of necessity.

Thirty years ago, the concept of planet formation was much more orderly than it is today. A star formed at the center of a rotating disk of preplanetary material. Gradually, the material condensed and gathered in eight planets (besides Pluto) in simple orbits.

However, when Hal Levison, a planetary scientist, and other theorists tried to simulate the formation of the solar system, they ran into a problem repeatedly: It was nearly impossible to construct Uranus and Neptune in their current orbits. To explain these worlds, known as ice giants, Dr. Levison and three other researchers developed the Nice model of solar system evolution (named for the city in France).

The model suggests that giant planets form much closer to the sun than their current orbits, and that the increasingly eccentric orbits of young Jupiter and Saturn are destabilizing and rearranging the solar system. In the process, they dispersed the smaller bodies of the solar system as the giant planets moved and Uranus and Neptune bordered outward. Some comets and asteroids were launched into the deep outer solar system, while others were launched entirely into the Milky Way.

A small minority of scattered asteroids are trapped at two of Jupiter’s permanent Lagrangian points, regions of space where the gravitational and orbital effects of the planet and sun are balanced. The zones both rule and follow Jupiter in its orbit. These asteroids are Trojan swarms.

Today, the Nice model offers a dominant understanding of how a disk of dust and gas became a system of planets orbiting the sun about 4.6 billion years ago. Also, telescope observations of exoplanets have led to a broader scientific reassessment of how star systems, including ours, could form. Some distant stars are orbited by giant planets that are closer to them than Mercury is to our sun.

Dr. Levison came to believe that the planetary science community’s ideas about planet formation were outpacing the available data. The best way to limit variables in the nice model would be to explain the origin of Trojans.

“One of the surprising things about the Trojan population is that they’re very different from each other physically, but they really occupy a small region of space,” he said. “This diversity in this small region tells us something important about the early evolution of the solar system.”

To understand the secrets locked in the orbits of the Trojans, Dr. Levison needed to persuade NASA to build a spacecraft to study them and determine what had formed where. Lucy’s result. Selected for flight in 2014 NASA’s Discovery Programwhere scientists compete on smaller mission proposals.

Analyzing the footage will be an important part of the Lucy team’s scientific efforts. The surface age of an object is revealed by counting the number of craters detected in each asteroid. (More impactors will hit the older surfaces and therefore show more craters.) The scientists will also analyze images rotated for color distribution across the asteroids’ surfaces, which could be an indication of what the rocks are made of: Thermal measurements will help determine the asteroids’ compositions and structures. . They will also use infrared spectra to measure the presence of minerals, ice and organic molecules.

NASA is interested in finding primordial organic material on asteroids because they may have planted essential chemical components for life on Earth billions of years ago.

Although the Trojans share an orbit with Jupiter, Lucy will not visit Jupiter. Before the spacecraft launches from Earth, it will be closer to Jupiter than when it visited the Trojans.

During its 12-year mission, it will be powered by two giant solar panels that stack during launch and gradually expand outward like folding fans. Lucy’s roller coaster-like orbit will carry her farther than any solar-powered spacecraft has ever flown. And it will move at about six miles per second at its fastest clip.

Dr. “His speed will be like running 10,000 per second,” Olkin said.

The spacecraft will be in a complex cyclic orbit throughout the solar system, circling the sun, borrowing gravity from Earth to push it free into Jupiter’s orbital path at a point known as Lagrange 4. Gravity will pull it back around the sun. to Earth, whose gravity will throw it out again, this time to Lagrange 5 and back, the process repeats. The orbit is driven by the positions of the planets and their gravitational aids, meaning the spacecraft will continue to do so for hundreds of thousands—if not millions—of them if nothing stops it.

Each encounter will be 600 miles or less above the surface of Troy. After the final flight, depending on Lucy’s health, NASA may target future asteroids and other celestial bodies for analysis.

Dr. “We get data as we fly past a Trojan asteroid,” Olkin said. Lucy’s science instruments are mounted on a mobile beacon platform attached to the spacecraft. Tracking cameras feed images to onboard computers that keep the science instruments locked onto the target regardless of the spacecraft’s position. Lucy will collect data for each full rotation of each asteroid, some spinning faster than others.

The probe will reach its first target in 2025, an asteroid between Mars and Jupiter named 52246 Donaldjohanson, after the discovery of the Lucy skeleton. It’s not a Trojan horse and more like a rehearsal flight for the mission. During their observation campaign, scientists discovered that Donaldjohanson was most likely only 100 million years old, making it one of the youngest objects in the solar system and a target of exploration in itself.

Two years later, the spacecraft will fly past 3548 Eurybates, the first Trojan asteroid that also has a small moon, Queta. Eurybates was once part of another destroyed asteroid. Such an origin could also explain its moon. The second target, 15094 Polymele, is the smallest of the non-lunar targets for Lucy. Planetary scientists will be looking closely at surface properties and density. In general, objects formed closer to the sun are denser than objects formed farther away.

The spacecraft will then fly alongside the asteroid 11351 Leucus, a “slow rotator” whose day lasts about 400 hours. Its shape is particularly interesting. The last asteroid of the first cycle of Lucy’s orbit is 21900 Orus. Scientists are interested in the differences between its terrestrial and Eurybates.

In 2028, Lucy will begin scanning from one side of the solar system to the other to visit the opposing Trojan horde. After crossing Earth to gain speed, the spacecraft will fly to 617 Patroclus and Menoetius, binary asteroids orbiting a common center of mass, in 2033. These are among the largest known Trojan bodies, and scientists want to know if their match is a sign that they came from the solar system, where such binaries are more common.

After this final planned encounter, the mission could be expanded by NASA to study smaller objects. But even if the mission ends in the 2030s, there may be another action: Lucy will continue to soar through Jovian Lagrange points and swing back and forth around the Earth. Therefore, the agency placed Lucy in a “time capsule” of poetry, quotes and lyrics. As in the prehistoric times of the 21st century.

If Lucy returns data showing that Trojans formed in different places at different distances from the sun and then drifted into their current orbits, there would be substantial evidence to support this Nice model.

On the other hand, when Lucy’s main mission is complete and all the data is back, something completely unexpected may have emerged about how the solar system evolved. That says the mission leader would be a good thing.

“My hope,” said Dr. It would be “looking at current patterns of solar system formation, including my own work, and saying, “No, they’re all wrong,” Levison said. It wasn’t that simple, and we have to start over.”