Near Earth Asteroid Rendezvous Shoemaker

Near Earth Asteroid Rendezvous Shoemaker (NEAR Shoemaker), first spacecraft to orbit and then land on an asteroid (Eros, a near-Earth asteroid, on Feb. 12, 2001).

The NEAR spacecraft was launched by the U.S. National Aeronautics and Space Administration on Feb. 17, 1996. Its destination, Eros, was the second largest known asteroid in an Earth-crossing orbit; the asteroid is roughly the size of the Caribbean island country of Barbados. The spacecraft’s trajectory took it as far from Earth as 330 million km (205 million miles); it then returned to Earth for a gravity assist, passing as close to the planet as 540 km (335 miles). On June 27, 1997, NEAR flew within 1,200 km (740 miles) of Mathilde, an asteroid in the main belt between Mars and Jupiter. Rendezvous with Eros was originally scheduled for January 1999, but a spacecraft problem delayed the rendezvous for more than a year until Feb. 14, 2000—Valentine’s Day, a date chosen because the asteroid was named for the Greek god of love. At the time of rendezvous, the spacecraft was renamed NEAR Shoemaker in honour of geologist Eugene Shoemaker, a pioneer in the study of asteroid impacts, who had died in an automobile accident in 1997.

During a year spent in close orbit (5–56 km [3–35 miles]) around Eros, NEAR Shoemaker studied the object’s mass, structure, geology, composition, gravity, and magnetic field. The surface of Eros had both very smooth, flat areas and regions covered with large boulders. NEAR found that Eros, unlike the planets of the solar system, had not undergone extensive melting and differentiation into distinct layers. On Feb. 12, 2001, the spacecraft survived a landing on the surface of Eros, returning images of objects as small as 1 cm (0.4 inch) across during its final descent and sending back scientific data from the asteroid’s surface for a few more days after landing. Communication with NEAR was ended on Feb. 28, 2001. On Dec. 10, 2002, an attempt to reestablish communication with NEAR failed.