Now the fun starts.
A 15-second engine burn at 1 p.m. EST on March 3 will
nudge NEAR into a 124-mile (200-kilometer) orbit around Eros, giving the spacecraft its best scientific look
at the asteroid so far. Over the next four weeks, NEAR will collect images and data for a detailed global
surface
map, a topographic model and a more precise estimate of gravity on Eros.
“We expect to resolve a lot of the features that we’ve only seen glimpses of,” says Louise Prockter, a
member of NEAR’s imaging team.
NEAR’s Multispectral Imager will snap enough photos to create color and monochrome maps of Eros’
surface. By
measuring the distance between NEAR and Eros, the Laser Rangefinder will begin to shape three-dimensional
perspectives of the craters, ridges and various other
features in the images. The craft’s radio science
equipment will use the closer orbit to get a better
reading of the asteroid’s gravity field.
With a little help from the sun, the satellite could
also get its first readings of the asteroid’s elements. The X-Ray Spectrometer detects fluorescence from
elements that react to solar x-rays. “A lot depends on solar activity,” says Ralph McNutt, X-Ray/Gamma
Ray Spectrometer instrument scientist. “If there is a strong solar x-ray event, the instrument will get a good
measurement.”
Moving 3 miles an hour relative to Eros, NEAR will
circle the rotating space rock three full times during this orbit. NEAR operates at this range until April 1,
when another short engine burn will gradually move it
into a 60-mile (100-kilometer) orbit. The asteroid and spacecraft are about 152 million miles (almost 245
million kilometers) from Earth.
The NEAR team will analyze and present its findings from the orbit over the next several months, including a
potential first look at the data during a March 13 press briefing at the Lunar and Planetary Science
Conference in Houston.
