Skip Navigation: Avoid going through Home page links and jump straight to content
spacer spacer spacer
spacer spacer spacer
spacer
NASA Logo    + View the NASA Portal  
Near Earth Object Program
spacer
spacer spacer spacer
spacer
NEO Basics Search Programs Discovery Statistics Space Missions News Frequently Asked Questions
spacer
spacer spacer spacer
spacer
Orbit Diagrams Orbit Elements Close Approaches Impact Risk Images Related LInks
spacer
spacer spacer spacer
spacer

NEAR-EARTH ASTEROID RENDEZVOUS (NEAR)

Near-Earth Asteroid Rendezvous (NEAR): Launched on Feb. 17, 1996 the NEAR spacecraft made successful flybys of asteroid 243 Mathilde on June 27, 1997 and asteroid 433 Eros on December 23, 1998. The spacecraft then returned to asteroid Eros and on February 14, 2000 the spacecraft went int o orbit around Eros. Beginning with an orbit of about 320 x 366 km above Eros, a series of maneuvers put the spacecraft in lower and lower orbits and during the summer of 2000, the spacecraft spent several weeks in a near circular orbit of only 35 km from the center of Eros in 2000 and 2001.

Although the NEAR spacecraft was originally scheduled to rendezvous and orbit asteroid Eros in mid-January 1999, a scheduled main engine firing on December 20, 1998 failed to take place. As a result, the spacecraft flew past Eros at 4,100 km on December 23, 1998 at a relative velocity of about one kilometer per second (2230 mph). However, a successful main engine firing on January 3, 1999 allowed the spacecraft to catch up with Eros in mid-February 2000. The spacecraft was built by the Johns Hopkins University's Applied Physics Laboratory. The images of asteroid Mathilde taken by the NEAR spacecraft show 4-5 very large craters that were formed when other asteroids slammed into it long ago. Mathilde may have survived these collisions intact only because it seems to be a collection of rocky fragments (a rubble pile) rather than one monolithic rock. A rubble pile asteroid can more easily absorb the impact energy during a collision without breaking apart. By analogy, a bag of sand (rubble pile) can withstand a blow by a hammer but a solid, monolithic brick could not survive a blow of this type without shattering.

From the measurement taken while the spacecraft was in orbit about Eros, the asteroid's surface has been mapped, and determinations made for its size, shape, rotation rate, mass, density and composit ion. These Eros results have been presented in a series of four papers published in the weekly journal, S cience Magazine (dated September 22, 2000, volume 289, pp. 2085-2105). The earlier scientific result s for asteroid Mathilde were also published in Science magazine (volume 278, pp. 2106 2114, 1997).

NEAR Science Instruments:
Imager, IR spectrometer, x-ray/gamma ray spectrometer, magnetometer, lidar

Johns Hopkins University's Applied Physics Laboratory built the spacecraft and provides the project management.

Look here for additional information on the NEAR mission:

http://near.jhuapl.edu/

Image of Eros taken by NEAR
Image of Eros taken by NEAR

Menu
FIRST GOV   NASA Home Page Site Manager: Don Yeomans
Webmaster: Ron Baalke
Last Updated:
Feedback Credits Privacy Mailing List NASA