Helen Worth
The Johns Hopkins University
Applied Physics Laboratory
Laurel, Md. 20723
Phone: (240) 228-5113

Doug Isbell
NASA Headquarters
Washington, D.C.
Phone: (202) 358-1753

December 22, 1998

NEAR Spacecraft to Fly by Asteroid Eros on Dec. 23; 
Rendezvous with Eros in 2000 

A Dec. 20 spacecraft abort of the initial rendezvous
burn of the Near Earth Asteroid Rendezvous
(NEAR) spacecraft has resulted in a postponement
of NEAR's orbit of asteroid 433 Eros, originally
scheduled for Jan. 10, 1999. However, a flyby of
the asteroid is planned for Dec. 23, 1998, at 1:43
p.m. EST, that will provide valuable information for
its later study. 

"While the engine burn abort was unfortunate, we
still expect to accomplish the rendezvous
objectives, but at a later date," says NEAR Mission
Manager, Dr. Robert W. Farquhar, of The Johns
Hopkins University Applied Physics Laboratory,
which manages the NASA mission. "We expect that
the later rendezvous date will not diminish the
overall science return." 

During the Dec. 23, 1998, flyby, scientists will gain
a preview look at the asteroid and gain a global
perspective that will provide important information
in planning an orbit insertion. Mission designers
are now expecting the rendezvous will take place
by May 2000. Data obtained from the flyby will help
determine the shape and size of the asteroid and if
it has any moons. 

The rescheduling of the NEAR mission was made
necessary by the abort of a planned 20-minute
engine burn on Dec. 20, 1998. The spacecraft
aborted just seconds after initiation of the
bipropellant burn, causing communications with the
spacecraft to be lost for about 27 hours. Contact
was reestablished early Dec. 22, after NASA's
Deep Space Network locked onto a radio signal
from the NEAR spacecraft at about 8 p.m. EST, on
Dec. 21. 

Responding to a command from the Mission
Operations Center, NEAR started downloading
stored data early Dec. 22, which the mission team
has been analyzing to determine the cause of the
abort and why the spacecraft lost attitude control. 

"We've looked at the data and we believe there
has been no damage to the spacecraft or the
propulsion system," says spacecraft systems
engineer, Andrew G. Santo. "Our fault protection
software identified the problem and switched NEAR
to a safe mode. Essentially, it worked as
designed." 

During the Dec. 23 flyby NEAR will take
approximately 500 images from as close as 4,100
kilometers (2,500 miles). Although the images will
be of lower resolution than those taken June 27,
1997, during the flyby of asteroid 253 Mathilde,
they will provide scientists with important
information about the asteroid. 

NEAR will then travel in an orbit around the sun
that nearly matches that of Eros. In May 2000, the
spacecraft and Eros will meet, making it possible to
insert NEAR into orbit around the asteroid. 

NEAR was launched Feb. 17, 1996 as the first
launch of NASA's Discovery Program. Updates of
mission activities and science returns will be
posted on the Web site (http://near.jhuapl.edu)
and on the NEAR mission hot line: (240) 228-5413.