Jupiter’s Trojan asteroids are a key target of NASA’s Lucy Mission. Launched in October 2011, the spacecraft has traveled 1/3rd of the way to Jupiter and is expected to arrive at its destination in 2025. The mission will explore six Trojan asteroids that orbit with Jupiter, which were first discovered by astronomers using ground-based telescopes in 1906.
In addition to being fascinating objects, Trojans may hold important clues as to the origin and evolution of our Solar System. In a recent press release from NASA’s Goddard Space Flight Center, mission team members outlined their scientific goals as well as explained how they will meet those goals during its 20-year journey to the outer reaches of the Solar System.
The mission is named after the Roman goddess of love and beauty, who was also known as the huntress; this is in reference to the fact that the Trojans are associated with the myth of the Golden Age of heroes. It was during this age when people lived like gods, and untouched by age or death. This era was ended when the Trojan prince Paris stole the beautiful Helen of Troy, which started the Trojan War.
Lucy is expected to launch in October 2021 and travel for almost seven years before it settles into orbit around Jupiter in 2025. The mission will spend 20 months orbiting within the Trojan swarm, where it will study six of Jupiter’s 60+ known Trojans. During this time the spacecraft will fly by three main belt asteroids at different points in its orbit around the Sun.
After it finishes its observations of the Jovian Trojans, Lucy will then travel to a further target – an asteroid in the main belt between Mars and Jupiter. The name of this asteroid has yet to be decided, but it will become the second object ever to have its orbital path around the Sun studied by a spacecraft.
Lucy is visiting unique worlds that humankind has never seen before, said Dante Lauretta, principal investigator for the mission and professor of planetary science at the Lunar and Planetary Laboratory, University of Arizona. If you’d asked me a few years ago if we would ever know what Lucy was going to discover on its expedition to seven asteroids, I never would have believed it, but here we are!
On its trip to the Trojan asteroids, the craft will make use of the fact that all six orbit in the same direction in reference to Jupiter, but in different orbital planes. Eventually, this arrangement causes their paths to cross each other at various angles. The mission team intends for Lucy to fly by its targets at just 5 km/sec which is slower than a typical gunshot.
At these speeds, the spacecraft will need to pass through the swarm of thousands of asteroids moving together like a school of fish in order to make its observations. As they approach their target, the team plans to map their surfaces and study them using cameras. The craft itself is expected to have an array of six instruments on-board, which will study the Trojans in detail.
The mission’s main goal is to understand how these objects formed and evolved over time. Their proximity to Jupiter likely arose because they were once part of a larger asteroid that was drawn into orbit around it by its powerful magnetic field. As such, the Trojans are remnants of what is known as the protoplanetary disk, which encircled the young star at its birth.
Studying these objects can shed light on how planets form and evolve over time. If they formed closer to Jupiter, then it stands to reason that our own planet may have, as well. In addition, studying what these objects are composed of can help shed light on how planets form from the disk of material that encircled young stars.
The spacecraft itself was named after a mythological figure famous for her many talents. Able to move past obstacles using speed and intelligence, Lucy will do the same by using its instruments to gather the data it needs in record time.
The mission was selected for launch in 2016, when NASA received 28 proposals. Anyone who suggested an asteroid-related name (most of which were mythological figures) for this robotic probe had to be creative in order to be considered, given that 21 out of 25 asteroids that have been successfully discovered are named after women.
This is the only time in history so many asteroids have been explored, said Lauretta. The team will operate Lucy like a human pilot through each asteroid encounter to ensure we get the data we need.