Spacecraft Starts Voyage To Asteroid Probe Launched On 3-Year Journey

NASA launched a spacecraft Saturday on a three-year voyage to an asteroid that may contain clues to the birth of the solar system.

An unmanned Delta rocket blasted off at 3:43 p.m. with the probe, called NEAR for Near Earth Asteroid Rendezvous. Scientists described the launch, and their emotions, as “awesome” and “terrific.”

The NEAR spacecraft is bound for Asteroid Eros, one of the largest asteroids orbiting the sun relatively close to Earth. It should reach Eros in February 1999, following a 1.3 billion-mile journey, and become the first spacecraft to orbit an asteroid.

“We’ll get the first really good close-up look at an asteroid,” said project scientist Andrew Cheng of the Johns Hopkins University Applied Physics Laboratory.

NEAR will circle Eros for nearly a year, flying as close as 10 miles to its rocky surface. The potato-shaped asteroid is estimated to be 25 miles long, 9 miles wide and 9 miles deep, and may contain materials dating back to the origin of the solar system 4.6 billion years ago.

The next two months will be crucial as NEAR hurtles farther from Earth and its five science instruments gradually turn on. After that, it will be a matter of “keeping our noses to the grindstone and making sure we bring back the goods,” Cheng said.

Early signals from the bargain-priced spacecraft indicated it was on course and working well. “Like hearing that first cry from your newborn child,” Cheng said.

“It’s a great relief to sense that, well, we have gone over our first big hurdle,” he said. “Now our work is cut out for us. … We’ve got a lot of hope, a lot of expectations.”

NEAR will fly within 750 miles of another asteroid, Mathilde, in 1997, and then head back toward Earth for a gravity assist that will put the spacecraft on the same orbital plane as Eros.

Once at Eros, NEAR will measure the mass, density and composition of that asteroid and, hopefully, provide a better understanding of how Earth and the other planets formed. Scientists aren’t sure whether Eros is a fragment of a ruptured, former planet or a primitive celestial body that never evolved.