Lucy is a spacecraft designed to study Jupiter's Trojan asteroids. These chunks of ice and rock share the orbit of Jupiter, but they aren't near the giant planet. One clump is 60 degrees ahead of Jupiter, the other 60 degrees behind. They ae held in place by the gravity of Jupiter and the Sun. Astronomers have cataloged more than 5,000 of them, although there could be millions. Trojans probably are “leftovers” from the birth of the solar system. They contain the same materials that were incorporated into the planets, so studying them should tell scientists more about how the planets formed. Launched October 21, 2021, Lucy is scheduled to fly past one asteroid in the asteroid belt, between the orbits of Mars and Jupiter. It will reach one group of Trojans in 2027, and eventually swing by five of its members. It then will skip past Earth, using our planet’s gravity to reach the other clump in 2033.