A mosaic image of the asteroid 253 Mathilde captured by the multispectral camera on the Near Earth Asteroid Rendezvous (NEAR) spacecraft during flyby shows an extreme degree of cratering, including what is believed to be a single-impact gouge more than 10 km deep. The spacecraft acquired the images on June 27 at a distance of 2400 km from the surface of Mathilde, imaging some 60% of the asteroid at spatial resolutions as high as 380 m.
The NEAR spacecraft performed the flyby en route to the asteroid 433 Eros (see Laser Focus World, Sept. 1996, p. 77). Program scientists arranged the pass to provide a systems test of some of the spacecraft instruments. At the same time, the flyby provided some unexpected scientific data on Mathilde, including a material density significantly lower than that calculated from Earth observations. The abundance of craters in all images reveals a history of violent impacts and one of the highest crater-per-unit-area figures known. Astrophysicists now seek to determine the composition of the asteroid to understand how it sustained such a violent bombardment without fragmenting.
Next stop for NEAR is Eros, in early 1999. Over the course of a year, the spacecraft instruments will capture data on elemental composition, internal structure, and topology of the asteroid, providing information that will allow astrophysicists to better understand the formation and early evolution of the solar system.