Asteroid · Near-Earth asteroid (Amor) · orbits Sun
Eros is a peanut-shaped rock 34 km long and the first near-Earth asteroid ever discovered. In 2000 NASA’s NEAR Shoemaker probe became the first spacecraft to orbit an asteroid, and in February 2001, though it was never designed to land, it touched down so gently on Eros that it kept transmitting from the surface.
NEAR Shoemaker orbited Eros for a year, then landed on it in February 2001 - a first, twice over.
It was the first near-Earth asteroid ever found, spotted on photographic plates in 1898.
Escape velocity is only about 10 m/s - a thrown baseball would leave forever.
First contact with an asteroid
Orbiting a small, lumpy body is genuinely hard: Eros’ gravity field is so irregular that NEAR Shoemaker’s orbit had to be constantly redesigned around it. The techniques worked out at Eros - navigating, orbiting and finally touching down on a low-gravity world - opened the way for every later asteroid mission, from Hayabusa to OSIRIS-REx.
Physical characteristics
Diameter
17 km
Dimensions
34 × 11 × 11 km
Mass
6.690e+15 kg
Density
2.67 g/cm³
Rotation period
5.27 h
Geometric albedo
0.25
Atmosphere and composition
Atmosphere
None.
Composition
S-type: stony silicate rock (olivine and pyroxene) laced with metal grains.