Asteroid 433 Eros was the first near-Earth asteroid to be discovered a
nd nearly 100 years of ground-based observations have allowed a rough
physical characterization of the body. Eros is a S-type asteroid whose
dimensions are approximately 40.5 x 14.5 x 14.1 km. Its rotation is i
n a direct sense with a period of 5.27 hours and its geometric albedo
is 0.17. Good observing opportunities in late 1995 and several months
in 1998 will allow these physical parameters to be further refined. At
the time of the NEAR spacecraft arrival in early 1999, the Eros ephem
eris uncertainties will be less than 50 km based on ground-based astro
metric observations alone.