ALBUQUERQUE - The Near Earth Asteroid Rendezvous (NEAR) spacecraft is preparing to step down its altitude Friday and draw itself ever-closer to asteroid Eros.

Since it began its picture-snapping, data-snagging orbit around Eros on February 14, scientists have been delighted with NEARs performance. Closeup looks of Eros are stirring up ideas of how best to mine asteroids in the future.

"Things are going greatjust swimmingly" said Robert Farquhar, mission manager for NEAR at the Applied Physics Laboratory in Laurel, Maryland.

Ground controllers at the lab will fire the probe's thrusters on March 3, dropping NEAR down to a roughly 125-mile (200-kilometer) circular orbit around Eros, Farquhar told SPACE.com.

At that altitude, spacecraft controllers will be on the lookout for changes in NEARs orbit. The odd-shaped rock will likely begin to tug on the probe, possibly changing its orbit.

Given its low reserve of fuel, extra care is needed to avoid losing control of the craft. Irregularities in NEARs orbit will likely occur as it is influenced by the asteroids gravity field, Farquhar said.

Farquhar said NEAR will circle Eros at that altitude for one month, completing one circuit of the asteroid every 10 days. The spacecrafts altitude will drop another notch on April 1, he said, down to 62 miles (100 kilometers) above Eros rocky surface.

Robert Reedy, a member of the NEAR science team and staff member at the Los Alamos National Laboratory, said that with each drop in altitude above Eros, our view of the asteroid will surely change.

"Were going to have a lot more information as we get lower. We dont know what minerals are there and how Eros has evolved. We are just getting that data in," Reedy said.

Reedy, a speaker at the Space 2000 Conference and Exposition on Engineering, Construction, Operations and Business in Space, said this mission is not an overnight project.

"One problem is that we dont yet see the southern pole of Eros right now. Its in perpetual night," he said. "Were moving from the sun on the northern hemisphere toward the [south]. Its going to be many months before we will have a full picture of the whole asteroid. Thats one advantage of staying around. You do get to see the whole object," he said.

One early observation from NEAR's photos of Eros is that the asteroid may be covered with a dirt-like surface, much like the moon, called regolith.

"When we get up close well get a better idea, but it does look like asteroids have regolith," Reedy said. "You would think with these objects being impacted, you would loose that material. But the indications are that there is a coat of regolith. Again, by getting closer, well have a better idea. Is it a very fine material like the lunar regolith? How deep is it? We really have to get up close and personal to find out," he said.

There are still worries as NEAR draws closer to Eros. It could run into natural satellites or debris that may be lurking about the heavenly body.

"Thats one reason why were studying it very carefully. You dont want to start coming in and suddenly get hit by something you didnt know about," he said. "But there hasnt been any sign of any objects as yet. Thats why were not coming in very fast. But were still looking."

The yearlong mission will end on February 14, 2001. Both money and lack of fuel will surely bring NEARs mission to a close, Reedy said.

"When the money runs out, we might as well as bring it down to the surface and leave it there," he said.

Mark Sonter, a mining specialist in Hawthorndene, Australia who heads Asteroid Enterprises Limited, is eagerly awaiting new photos and new data from NEAR. He sees comets and asteroids as the resources for space-based industry in the 21st century.

Sonter said that Eros photos have already provided one clue for future asteroid miners.

"What is interesting about seeing the slumps in the craters on Eros is that these slumps are a natural gravity-sifting mechanism," he said. "They put the heavier metals at the bottom and the lighter ones at the top. Thatll make it a lot easier for mining."

"Eros is interesting. It again confirms the presence of an apparently thick, loose, sandy gravel on top that is inherently easy to mine," Sonter said.

There may be a possible surprise, Sonter said, from NEARs flyby of the battered but not busted-up asteroid Mathilde in 1997: we may have had an up-close look at the burned-out hulk of a comet.

"The interesting thing about Mathilde is that you have these huge, scalloped craters on the surface. They are gigantic craters equal to the blooming radius of the whole object," Sonter told SPACE.com. "It might simply be a highly porous object and thats why it might have absorbed such huge craters without falling apart.

"It could be that Mathilde is an extinct comet. Its either a microscopic, reassembled rubble pile or something that was inherently a highly porous body from scratch. And if its the later, then it was probably a comet to start with."