There are countless asteroids in our solar system. Most of them are located in the main asteroid belt, i.e., a region between the orbits of Mars and Jupiter. And this torus-shaped region contains many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called asteroids or minor planets. These Trojan asteroids share an orbit with a planet near stable points in front of or behind the planet. Because they constantly lead or follow in the same orbit as the planet, they never can collide with it. In our solar system, Trojans also share orbits with Neptune, Mars, and Jupiter. The Mars and Jupiter belt is estimated to contain between 1.1 and 1.9 million asteroids larger than 1 kilometer (0.6 miles) in diameter, and millions of smaller ones. Asteroids that come close to Earth are called Near-Earth Objects, NEOs for short. NASA continuously monitors NEOs. Asteroids are leftover from the formation of our solar system. In the region between Mars and Jupiter, it appears that one or more planets could have formed, but the gravity from Jupiter kept pulling things apart. Instead of forming a single planet, the material in this region was only ever able to form into asteroid-sized objects. The orbits of asteroids can be changed by Jupiter's massive gravity – and by occasional close encounters with Mars or other objects. These encounters can knock asteroids out of the main belt, and throw them into space in all directions across the orbits of the other planets. Scientists continuously keep a close eye on asteroids, whose paths intersect Earth's orbit, and near-Earth asteroids that approach Earth's orbital distance to within about 28 million miles (45 million kilometers) and may pose an impact danger. These asteroids gather around two special places in the orbit. One is the Jupiter trojans and there are Mars and Neptune trojans. NASA announced the discovery of an Earth Trojan in 2011. No spacecraft has ever been to these Trojan asteroids. Now, a new NASA Discovery Program mission called Lucy spacecraft has been launched on Oct. 16, 2021. NASA’s Lucy mission, the agency’s first to Jupiter’s Trojan asteroids, launched at 5:34 a.m. EDT Saturday on a United Launch Alliance (ULA) Atlas V rocket from Space Launch Complex 41 at Cape Canaveral Space Force Station in Florida. Over the next 12 years, Lucy will fly by one main-belt asteroid and seven Trojan asteroids, making it the agency’s first single spacecraft mission in history to explore so many different asteroids. Lucy will investigate these “fossils” of planetary formation up close during its journey. According to David Dezell Turner, Southwest Research Institute, Boulder, Colorado “Southwest Research Institute in Boulder, Colorado, is the principal investigator institution and leads the science investigation. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and safety and mission assurance. Lockheed Martin Space Systems in Denver is building the spacecraft. Spacecraft payload is being provided by Goddard, the Johns Hopkins University Applied Physics Lab, and Arizona State University. The Discovery Program management is executed by NASA’s Marshall Space Flight Center in Huntsville, Alabama.”