The operation to adjust the crafts orbit is delicate because the asteroids gravity is so weak, a baseball tossed off the surface could fly off into space, scientists say.
Engineers burned the crafts engine for a bit over two minutes to halve its orbit from 62 to 31 miles (100 to 50 kilometers) Sunday afternoon, the operators said. Thats the sixth time the thrusters have been fired to adjust its position.
The operators will keep NEAR at its present orbit, collecting images and data until July 7, then try to lower it to an orbit of about 22 miles (35 kilometers), Worth said.
Next, "In mid-summer were going to meet with NASA and find out how the mission is going to end. We may get much closer," she added.
One option is to touch down on the asteroid. This is a risky operation that could destroy the craft, Worth said. But engineers may try to bring the device down to the surface and lift it back up to see its imprint and clarify how soft the surface is, she added.
The craft is jogging at 7 m.p.h. (11.2 kilometers per hour) around the potato-shaped asteroid, engineers said. Thats a reduction of 3 m.p.h. (4.8 kilometers per hour) from its previous speed.
The closer NEAR gets, the more accurate each adjustment must be to keep the craft in proper orbit, because of the increasing gravity approaching the surface, according to the engineers.
NEAR carries devices to measure the shape, mineral content and gravitational field around Eros, among other things.
Scientists want to study asteroids for many reasons. These include the fact that asteroids have hit Earth with devastating results and doubtless will do so again, though probably no time soon.
Eros is about twice the size of Manhattan, and the largest asteroid near Earth. That makes it a logical candidate for examination. Scientists say it wont hit earth within the next million years based on its present trajectory, but that could change if some other object knocks it off course.
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