16 Psyche

16 Psyche is a large M-type asteroid discovered by the Italian astronomer Annibale de Gasparis on 17 March 1852 and named after the Greek goddess Psyche. The prefix "16" signifies that it was the sixteenth minor planet in order of discovery. It is the largest and most massive of the M-type asteroids, and one of the dozen most massive asteroids. It has a mean diameter of approximately 220 kilometres (140 mi) and contains about one percent of the mass of the asteroid belt. 
Historically, it was hypothesized to be the exposed core of a protoplanet, but numerous recent studies have all but ruled that out. 
== Mission ==
Psyche will be explored by a spacecraft of the same name, marking the first time a man-made object will journey to a metallic asteroid. Launch is planned for no earlier than 5 October 2023, with an expected arrival in 2029.
Category:Asteroids
Category:Main Belt
Category:Objects Not in Hydrostatic Equilibrium
Category:Objects with No Atmosphere
Category:Other Spectral Types
Category:Named Objects
Category:Named Minor Planets
Category:Numbered Objects
Category:Numbered Minor Planets