Near-Earth Objects or NEOs are those asteroids that have escaped the confines of the main belt.They roam freely among the planets of the inner Solar System in which Earth is the largest target.Asteroid 433 Eros was the first discovered to have left the main belt and crossed the orbit of Mars.Eros comes within 13 million miles of Earth's orbit. In March 1932, another Mars-crossing asteroid was discovered with a perihelion of 1.08 AU. It was given the name 1221 Amor. It became the prototype Mars-crosser with a perihelion between 1.0 AU and 1.3 AU.
