Later this month, NEAR is set to make daring flybys of Eros. Pictures clicked during the maneuvers will show the greatest detail to date of various features on the celestial hunk.

"Everything continues to go swimmingly," said Robert Farquhar, NEAR mission manager at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. "Right now, NEAR is doing just fine," he told SPACE.com.

APL designed, built and is managing the NEAR mission for NASA.

Now being orchestrated is a progression of low-altitude flybys of Eros by NEAR.

The spacecraft is set to zoom down between January 24 and 28, skimming over the ends of the asteroid as it somersaults through space. NEAR may get as close as about 1.6 miles (2.5 kilometers) above the asteroids surface, Farquhar said.

Last October, NEAR whisked by Eros at approximately 3 miles (5.3 kilometers) above its surface, shooting over the asteroid at about 14 miles per hour (6 meters per second).

"What we have seen so far in the low orbits has merely whetted our appetite for more," said Andrew Cheng, NEAR project scientist at APL. "We went up close to have a better look at the surface than ever before, but we now see things we do not understand, and we need more information," Cheng said.

NEARs finale on February 12, swooping down and striking Eros, should give scientists photos that are 10 times better in resolution than anything received. Images from only 1,640 feet (500 meters) above the asteroids surface are expected.

By firing NEAR's rocket engines just before making asteroid contact, at a speed of 7 miles per hour (3 meters per second), the craft may hit, then bounce off Eros. Spacecraft cameras are to be busy during the risky controlled landing, the worlds first touchdown on an asteroid.

"But the uncertainty is pretty large. Who knows what NEAR will do," Farquhar said. "Even if its a crash landing...its a first landing," he said.

NEAR was not built to be a lander. The spacecrafts set of delicate solar arrays and other hardware will likely succumb to any hard-hitting arrival.

Scott Murchie, NEAR science team member at APL, said that landing on Eros is gravy, contrasted to the rich bounty of data already gleaned.

"To be honest, with 150,000 images, nobody has had the chance to look at all of them in detail. Were constantly going back and discovering interesting details in images that weve taken months ago," Murchie said.

That in-depth survey of Eros has revealed numbers of surprises.

"One thing weve found is that the surface layer is unexpectedly complex," Murchie said. That surface covering, called regolith, is not dotted with as many smaller craters as expected, he said.

Furthermore, the regolith appears relatively mobile, Murchie said, moving about like a fluid and has "ponded" in certain areas. "So theres a complicated geological story in the very small-scale surface features," he said.

For Cheng, having more mysteries than answers simply means more work ahead.

"Perhaps it will not be us, but some future scientists, who will unravel some of the mysteries we are studying. In any case, we are working hard to understand the surface of Eros," Cheng said.