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Come Closer, My NEAR

433 Eros
HELLO, EROS. On December 23, the NEAR spacecraft sent back its first images of the 433 Eros asteroid. Taken from a distance of about 3,300 miles, the smallest resolved detail of the 20-mile-long space rock is approximately 1,650 feet across.

Two years is a long time to travel for a blind date, especially if it's a rather homely piece of rock hurtling through space. But the intrepid Near Earth Asteroid Rendezvous (NEAR) spacecraft appeared to be right on time for a planned January 11 meeting with asteroid 433 Eros. Then, on December 20, NEAR faltered. When ground controllers fired the spacecraft's engines to slow NEAR down in preparation for being placed in orbit around Eros, the engines overheated and were shut down by automatic systems on the spacecraft.

Controllers successfully regained control of the spacecraft and fired its engines on January 3. But the delay cost NEAR a year. On its new course, NEAR's velocity has been matched to that of Eros. Since the spacecraft is slightly closer to the sun, it will gradually overtake the asteroid--but not until February 2000.

NEAR, however, made the best of missed opportunity. As it sped past Eros on December 23, controllers turned on the spacecraft's instruments, giving NEAR its first glimpse of its objective. At its closest, NEAR passed within 2,500 miles of Eros; it sent back 28 multicolor images, near-infrared spectra, and magnetic-field measurements. Eros was selected because it is the largest of the menacing "near-earth asteroids." Shaped rather like a peanut, Eros is about 20 miles long.

Trajectory

Eros is the second asteroid visited by NEAR. After its launch in February 1996, NEAR spun on an elliptical orbit into the solar system. The serendipitous discovery that it would pass close to an asteroid called Mathilde on June 27, 1997, gave controllers their first chance to test NEAR's instruments. NEAR then flew back by Earth, where it used the planet's gravity to sling it out of the plane of the planets and on a course that would intersect with the orbit of Eros.

Despite the setback, controllers at Johns Hopkins University's Applied Physics Laboratory are confident that NEAR will complete its scientific mission of providing the most detailed information yet about the composition of asteroids. The plan is for NEAR to maintain a close orbit around Eros gathering data for one year. Then it will attempt to make a "soft" crash landing on the surface of the asteroid.

The wait may be a bit longer because of the glitch, by the new arrival date seems auspicious. What could be better than Valentine's Day in the year 2000?


Images: NEAR
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