Eros From Orbit
On February 14th,
the NEAR spacecraft became
the first artificial moon of an asteroid.
Captured by the gentle gravity of a 20 mile long
slipper-shaped mountain of rock, NEAR recorded
this premier image while
orbiting asteroid 433 Eros at a distance of about 200 miles.
The image shows features as small as 100 feet across in a view
dominated by a 3 mile wide crater near Eros' narrow waist.
Enticing
layers and grooves are visible within the crater rim along
with an enormous 170 foot boulder lying on the crater floor
(near picture center).
Although Eros is a
large S-type near-earth asteroid,
it is still not massive enough
for its own gravity to have shaped it into a
planet-like spherical form.
By comparison, Eros has less than a thousandth Earth's gravity, so
a 100 pound object on Earth would weigh about 1 ounce
on Eros.
A baseball thrown at 22 miles per hour would
completely escape into space.
The weak gravity and irregular shape make orbiting Eros
a delicate challenge
for NEAR's controllers who
plan a year long exploration program with possible
close approaches to
the asteroid's surface.