Previously, NEAR imagery was being taken of the northern sections of the asteroid that were bathed in sunlight.

Curved trough on Eros is seen in this mosaic of seven images.

"Each picture we've taken is only a tiny fraction of the surface," said Andrew Cheng, NEAR project scientist at APL. "What we have are a lot of tiny postage-stamp-sized pictures. Now we've got to assemble them all together," he said.

It's like putting together a big jigsaw puzzle. It's a big task," Cheng said.

Eros has been far from a disappointing hulk of a world.

"There certainly has been a huge range of features. There's an amazing diversity of things we didn't expect to see," Prockter said. "It is like being a detective. The closer in you get, the more evidence you gather to test theories," she said.

Prockter said that Eros was expected to be a pretty bland, beat-up and heavily cratered object.

"The big surprise to us was the region nicknamed 'Saddle'. It's just a bizarre feature. One side looks like an impact crater, but on the other side there are all those very closely spaced groves coming out. That is just weird, something we can't explain at the moment," Prockter said.

Cheng also said the variety of landforms present on Eros is striking. In fact, the asteroid may serve double-duty in yielding its secrets.

The saddle feature on Eros.

"Most of us are persuaded that there is a subset of features on Eros that are more recent. Then there are other features that are older, dating back to when Eros was part of a much larger body," Cheng said.