On October 16, NASA's Lucy asteroid probe will begin its 12-year odyssey to study the Trojan asteroids. The spacecraft will hitch a ride into the cosmos aboard the United Launch Alliance Atlas V 401 rocket, Mike Wall reports for Space.com. Over the next decade, the spacecraft will whip past eight asteroids near planet Jupiter. The Lucy probe will visit more asteroids than any other spacecraft in history. NASA researchers hope Lucy will reveal elusive details of how our solar system formed more than 4 billion years ago.
The Trojan asteroids are two clusters of celestial fragments leftover from the formation of Jupiter, Saturn, Uranus and Neptune, reports Ashley Strickland for CNN. From Earth, the asteroid clusters appear as specks of light, per Popular Science's Charlie Wood. Both asteroid groups circle the sun, with one group circling ahead of Jupiter and the other trailing behind it, according to NASA. In total, 7,000 asteroids make up the Trojan clusters.
After launch, the probe will make several laps around Earth to use its gravity to propel itself further towards Jupiter. Throughout Lucy's mission, the spacecraft will swing back into Earth's orbit three times for gravity assists that push it towards the right path. In total, Lucy will travel four billion miles on its trek toward the asteroids. The spacecraft is expected to reach the Trojan asteroids in 2027.
Lucy will explore one "main belt" asteroid between Mars and Jupiter before visiting seven Trojan asteroids. The probe will observe Eurybates, Queta, Polymele, Leucus, Orus, Patroclus, and Menoericus—each named after characters in Homer's The Illiad, per CNN. Lucy will view each celestial object from 600 miles away, Popular Science explains.
"Amazingly, many of these mysterious worlds have been altered very little in the 4.6 billion years since they first formed," Lori Glaze, the director of NASA's Planetary Science Division, tells CNN. "The relatively pristine state makes comets, asteroids, and some meteorites wonderful storytellers that have preserved clues they can share with us about conditions in the early solar system."
Because these asteroids are fossil-like remnants of our solar system's origins, the space mission's name is a nod at our own evolutionary roots as humans. The probe was named after Lucy, the skeleton of a female hominid of the species Australopithecus afarensis, discovered in 1974 in Ethiopia. Lucy's skeleton changed how scientists viewed evolution and confirmed that our ancient ancestors walked upright before bigger brains evolved. Both the Lucy fossil and NASA mission allude to the Beatles song, "Lucy in the Sky with Diamonds," which is why the mission's logo is shaped like a diamond, per CNN.
The spacecraft will collect data and images of the Trojan asteroids using colored and infrared cameras. Other infrared instruments will detect how much heat each asteroid releases. Depending on how much the spacecraft is pulled or tilted towards an asteroid, NASA scientists can determine the object's mass, Popular Science reports.
Lucy measures more than 46 feet wide and stands about 24 feet tall. The probe is equipped with solar arrays on its main body that power up its instruments. Each camera will enable Lucy to study the surface of the asteroids, detect traces of water or minerals, and count craters or rings, per Popular Science.
After Lucy's mission ends in 2033, the spacecraft will become sapce junk, looping and retracing its orbit for many years to come, reports Popular Science.