This montage of the asteroid Eros was assembled from images acquired by the Near Earth Asteroid Rendezvous (NEAR) spacecraft on Dec. 23, as the spacecraft flew by the asteroid at a distance of 2,500 miles (4,100 kilometers) at 1:43 p.m. EST. This montage shows the first nine of 28 views of Eros that were obtained during the flyby. The images were taken between 10:44 AM and 12:44 PM EST as the spacecraft range closed from 7300 miles (11,100) km to 3300 miles (5300 kilometers). During that time, the asteroid completed nearly half of a rotation. The smallest resolved detail is approximately 1650 feet (500 meters) across.
A firing of the main engine at 5 PM EST December 20, designed to slow the spacecraft for insertion into orbit around the asteroid, was aborted by the spacecraft. Contact with ground controllers was temporarily lost, but was regained at 8 PM EST December 21 when autonomous spacecraft safety protocols took over and transmitted a signal to the ground. All spacecraft systems appear healthy and operational. Within hours, a flyby observation sequence was developed and uploaded to the spacecraft. Over 1100 images were acquired by the multispectral imager, to determine the size, shape, morphology, rotational state, and color properties of Eros, and to search for small moons. The infrared spectrometer measured spectral properties of the asteroid to determine what minerals are present, and the magnetometer searched for a natural magnetic field. Analysis of the spacecraft radio signal will yield bounds on the asteroid's mass and density.
Options for rescheduling firing of the main spacecraft engine are currently being examined, and could lead to Eros rendezvous and orbit insertion as early as mid-1999 or as late as May 2000. Eros is NEAR's second asteroid encountered. On June 27, 1997, NEAR flew by the main-belt asteroid Mathilde at a range of 1212 kilometers (750 miles).