Donald Savage
Headquarters, Washington, DC                  February 8, 2000 
(Phone:  202/358-1727)

Helen Worth
Johns Hopkins University Applied Physics Laboratory, Laurel, MD
(Phone:  240/228-5113)

RELEASE:  00-22

NEAR POISED FOR HISTORIC 
VALENTINE'S DAY EROS ASTEROID ENCOUNTER

     The NEAR spacecraft is straightening its orbit and 
putting its best solar panels forward as it approaches 
asteroid 433 Eros for a Valentine's Day rendezvous.  Its 
intended is a near-Earth asteroid named for the Greek god of 
love. 

     The NEAR (Near Earth Asteroid Rendezvous) mission, a NASA 
Discovery Program being conducted by the Johns Hopkins 
University Applied Physics Laboratory, Laurel, MD, is the 
first mission to orbit an asteroid.  For a year the spacecraft 
will use its instruments to scrutinize the potato-shaped space 
rock to learn about its chemical and physical features and 
evolutionary history. The asteroid is known to be 21 by 8 by 8 
miles (33 by 13 by 13 kilometers) -- about twice the size of 
Manhattan Island.

     NEAR is less than 2,900 miles (4,700 kilometers) from 
Eros and is slowly closing in at about 18 mph relative to the 
asteroid.  The spacecraft is alive with preparations for its 
rendezvous.  Its multispectral imager has been taking daily 
images for the past few weeks to confirm that the spacecraft 
is on track, to look for any moons orbiting the asteroid, and 
to measure its brightness variations for clues to its 
rotation. 

     The last scheduled rendezvous burn prior to orbit 
insertion will take place Feb. 8 at 5 p.m. EST.  On Feb. 13 at 
about 11:33 p.m. EST, the spacecraft will fly directly between 
the sun and the asteroid, enabling NEAR's near-infrared 
spectrometer to take critical observations of Eros' northern 
hemisphere under near-perfect lighting conditions, which will 
allow it to distinguish the asteroid's mineral composition.  
In October a similar sweep will be made over its southern 
hemisphere.

     On Feb. 14, at 10:33 a.m. EST, when NEAR is 207 miles 
(333 kilometers) from the center of Eros, it will fire its 
hydrazine engines to slow it enough to be captured by the 
asteroid's weak gravitational pull.  Confirmation of orbit is 
expected to come at about 11:30 a.m. EST to waiting team 
members in the Mission Operations Center on the Applied 
Physics Laboratory campus.

     During the first few weeks after achieving orbit the 
spacecraft will slowly descend toward the asteroid.  Because 
the asteroid is irregularly shaped and rotating (it rotates 
once every 5.27 hours), this early stage of the mission can be 
very tricky, says Dr. Robert Farquhar, NEAR mission director. 
"No one has ever orbited a small body in space," Farquhar 
says. "The orbital stability is rather tenuous, and as we 
travel around Eros our navigation maneuvers must be perfect to 
keep us from crashing into it."

     Using a multispectral imager, laser rangefinder, and 
onboard radio science experiment, mission scientists and 
engineers will acquire enough information on Eros' shape, mass 
and gravity field to allow the spacecraft to come closer. 
"Soon after we go into orbit we should know the asteroid's 
mass and therefore its density to within 5 percent," says Dr. 
Andrew Cheng, mission scientist.

     The onboard magnetometer will determine the strength of 
the asteroid's magnetic field -- if there is one.  "This will 
give the scientific community the first definitive measurement 
of an asteroid's magnetism, which contains clues to its 
thermal and geologic history," Dr. Cheng says.  "The results 
of these measurements and others that we will take over the 
next year will help us to determine the origin of the asteroid 
and give us an unprecedented understanding of asteroids in 
general."

     For the first two months NEAR will slowly descend to 
within 31 miles (50 kilometers) from Eros. During this low-
orbit phase the x-ray/gamma-ray spectrometer will measure 
elemental abundances -- important information to help 
determine the relationship between meteorites and asteroids.

     In late August the spacecraft will begin to climb from 31 
to 311 miles (50 to 500 kilometers) above the center of Eros. 
During this ascent the multispectral imager will continue to 
take images of the asteroid's surface that will be compiled 
into a complete map of the asteroid.  In December the 
spacecraft will descend, possibly to less than a mile, from 
the surface of the asteroid.  At that vantage point the near-
infrared spectrometer can collect extremely high resolution 
data of the asteroid's surface, making it possible to 
distinguish the composition of rocks as small as a grapefruit. 
Final events of the mission, which will end in February 2001, 
will be determined sometime this summer. 

NEAR was launched Feb. 17, 1996, from Cape Canaveral Air 
Station, FL.  Its original rendezvous date of Jan. 10, 1999, 
was postponed when a firing of the spacecraft's bipropellant 
engine, designed to put the spacecraft on target for the 
rendezvous, exceeded preset acceleration limits and caused the 
spacecraft to retreat into safe mode.  But valuable 
information about the asteroid was collected by a hastily 
programmed flyby of Eros on Dec. 23, 1998.  Early images can 
be found on the Internet at:  

                   http://near.jhuapl.edu

_________________________________________________________________				   
				   
Don Savage 
Headquarters, Washington, DC              February 8, 2000
(Phone:  202/358-1547)

Helen Worth 
Johns Hopkins University Applied Physics Laboratory, Laurel, MD
 (Phone:  240/228-5113)

NOTE TO EDITORS:  N00-4

EVENTS AND BRIEFINGS SET FOR HISTORIC ASTEROID ENCOUNTER

     On Valentine's Day 2000, NASA's NEAR spacecraft will 
probably be causing many hearts to beat faster than normal -- 
especially people in mission control.  They will be watching 
over the spacecraft as it makes its second attempt to gently 
enter orbit around the near-Earth asteroid Eros, named for the 
Greek god of love.  

     The NEAR (Near Earth Asteroid Rendezvous) mission, the 
first mission to orbit an asteroid, is being conducted for 
NASA by the Johns Hopkins University Applied Physics 
Laboratory, Laurel, MD.  Once in orbit, NEAR will begin a 
year-long scientific study to scrutinize Eros, including its 
chemical and physical features and evolutionary history.  The 
asteroid is about twice the size of Manhattan Island.

     The following activities are scheduled:  

               Feb. 14, 2000 -- Encounter Day

     9:15 a.m. - 11:30 a.m. EST - Rendezvous Activities at the 
Applied Physics Laboratory's Kossiakoff Auditorium.  Includes 
mission overviews and a live video feed from the Mission 
Operations Center during orbit insertion and confirmation.  To 
be broadcast live on NASA TV.

     2:00 p.m. EST - Press Briefing in the Kossiakoff Center.  
Includes rendezvous details and distribution of the first 
after-orbit insertion image.  To be broadcast live on NASA TV 
with two-way question-and-answer capability for reporters 
covering the event from participating NASA centers.

                         Feb. 17, 2000

     1:00 p.m. EST - Early Results Press Briefing in the James 
E. Webb Auditorium at NASA Headquarters, 300 E St. SW, 
Washington, D.C.  Includes early science return information 
and images.  To be broadcast live on NASA TV with two-way 
question-and-answer capability for reporters covering the 
event from participating NASA centers.

     NASA Television is broadcast on the GE2 satellite, 
located on Transponder 9C, at 85 degrees West longitude, 
frequency 3880.0 Mhz, audio 6.8 MHz.  Audio of the broadcast 
will be available on voice circuit at the Kennedy Space Center 
on 407/867-1220.

     Contact Helen Worth of JHU APL at 240/228-5113 for media 
accreditation to cover Encounter Day activities.

     Images and movies of Eros as NEAR closes in are available 
at:  

                      http://near.jhuapl.edu