A year after missing its target, a robotic space probe will have a second chance on Monday for a close encounter with an asteroid. As we travel around Eros, our navigation maneuvers must be perfect to keep us from crashing into it. During its planned year-long mission, NEAR is expected to relay detailed information about what the asteroid is made of, how it is held together, if it has a magnetic field and other attributes of the space rock. Scientists believe asteroids are leftover matter from the formation of the planets and the solar system.
Most asteroids orbit the sun in the asteroid belt, which is located between Mars and Jupiter.
Some like Eros, however, are near-Earth objects whose orbits swing close to our planet. Eros is currently about 240 million miles from Earth. Once in orbit, NEAR will gradually fly closer to the asteroid, slowly descending to about 31 miles from the asteroid's center. At that altitude, the spacecraft will use an X-ray and gamma ray spectrometer to look for elements such as magnesium, aluminum and silicon on the surface of Eros. NEAR will then be commanded to fly up to 311 miles so the spacecraft's cameras can fully map Eros' surface features.