They are considered to be debris left over from the formation of the solar system.Many asteroids orbit the Sun in a region between Mars and Jupiter. After being launched from Earth, the spacecraft will first make a quick flyby of a main belt asteroid in 2025. Hubble has observed the aftermath of some of these collisions. An asteroid is a rocky body in space which may be only a few hundred feet wide or it may be several hundred miles wide. 16 Psyche is one of the most massive objects in the solar system's main asteroid belt — and it appears to be made entirely of metal worth approximately $10,000 quadrillion. The mission will end this fall, when the spacecraft runs out of hydrazine, which keeps it oriented and in communication with Earth. Asteroids occasionally collide with each other. So far, NASA knows it is made up of silicate rocks, nickel, and iron. The asteroid belt in our solar system, located between Mars and Jupiter, is a region of millions of space rocks that sits near the “snow line," which marks the border of a cold region where volatile material such as water ice are far enough from the sun to remain intact. This "belt" of asteroids follows a slightly elliptical path as it orbits the Sun in the same direction as the planets. For example, the 3:1 Kirkwood gap is located where the ratio of an asteroid's orbital period to that of Jupiter is 3/1 (the asteroid completes 3 orbits for every 1 orbit of Jupiter). NASA's Dawn spacecraft turned science fiction into science fact by using ion propulsion to explore the two largest bodies in the main asteroid belt, Vesta and Ceres. The asteroid belt is about as wide as the distance between Earth and the Sun. Main Asteroid Belt: The majority of known asteroids orbit within the asteroid belt between Mars and Jupiter, generally with not very elongated orbits. Its surface is dark and muddy, but has hundreds of patches of bright material. Between the orbits of Mars and Jupiter is a mysterious dwarf planet called Ceres. Apophis originated from the asteroid belt between Mars and Jupiter. Get the latest updates on NASA missions, watch NASA TV live, and learn about our quest to reveal the unknown and benefit all humankind. That means there is plenty of room for spacecraft to safely pass through the belt. The belt is estimated to contain between 1.1 and 1.9 million asteroids larger than 1 kilometer (0.6 mile) in diameter, and millions of smaller ones. Radar images suggest it looks like a peanut . Martin and Livio suggest that the location of an asteroid belt relative to a Jupiter-like planet is not an accident. It’s a big space, so the objects in the asteroid belt aren’t very close together. Theories of asteroid formation predict that objects the size of Vesta or larger should form crusts and mantles, which would be composed mainly of basaltic rock, resulting in more than half of all asteroids being composed either of basalt or olivine. In fact, NASA has already sent several spacecraft through the asteroid belt! Hubble views extraordinary multi-tailed asteroid P/2013 P5.. One mystery of the asteroid belt is the relative rarity of V-type, or basaltic asteroids. NASA.gov brings you the latest images, videos and news from America's space agency.