NEAR Shoemaker

NEAR Shoemaker ( Near Earth Asteroid Rendezvous - Shoemaker ) is a launched probe the February 17th 1996 by NASA with an aim of studying in details one of the largest asteroids géocroiseurs: 433 Eros. The Sonde was finally posed on the Astéroïde the February 12th 2001 without suffering damage. The last signal of the probe was received the February 28th 2001.

Details on the mission

The June 27th 1997 the probe was to only 1800 km of the asteroid Mathilde, of which it did not take less than 500 stereotypes, and was then supposed to put into orbit around the Eros asteroid the January 10th 1999.

Following the failure of the engine and a temporary loss of the contact with the probe, it was necessary to await a revolution around the Sun before the probe finally could be put into orbit around the asteroid (to 50 km of altitude, the February 14th 2000).

It then could observe the asteroid under all the seams during nearly one year and, between April and October 2000, the probe established a complete cartography of the surface of Eros for finally being posed the February 12th 2001, by taking some ultimate stereotypes of surface.

The placing in orbit of the probe then its successful landing constitute a beautiful performance considering the low intensity and especially the heterogeneity of the gravitational field of Eros.

Results of the mission

The probe in particular made it possible to establish the first chart (of an accuracy of 3 meters) of the surface of an asteroid. The Matière is homogeneously distributed, which is not the case on other asteroids like Mathilde, which shows that he did not know stages of differentiation. The measurement of the gravitational field of the asteroid allowed a precise estimate of its mass (7 000 billion tons) and thus of its density equal to 2,7 - value rather close to that of the earth's crust. The number of craters on the surface made it possible to estimate the age of the asteroid at approximately a billion years. The knowledge of the surface of Eros also posed many problems. For example, the number of craters does not seem to obey the same laws as elsewhere: in general, the craters are all the more numerous as they are of small size, but on Eros, one counts many craters whose size is understood between 200 and 1 km, and almost not for a size lower than 20 m! Lastly, the probe has enabled to us thanks to his spectrometer x-rays to precisely know the composition of the surface of Eros: it is mainly made up of Pyroxène, Olivine and Silicium.

External bonds

NSSDC Master Catalog: Spacecraft - NEAR Shoemaker
NASA JPL: NEAR Shoemaker, Near Earth Asteroid Rendezvous

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