It has a mean diameter of approximately 220 kilometers (140 mi) and contains about one percent of the cumulative mass of the whole asteroid belt.

[8][6] Psyche will be explored by NASA, with a spacecraft of the same name, marking the first time a manmade object will journey to a metallic asteroid, launched on 13 October 2023,[12] with an expected arrival in 2029.

With more than a dozen asteroids discovered, remembering all their individual emblems became increasingly cumbersome, and, in 1851, German astronomer J.F.

[8][26] Assuming the mean volume of (5.75±0.19)×106 km3, this equates to a bulk density of 3.977±0.253 g/cm3, which is considerably higher than most small Solar System bodies.

[7][8][26] The first published three-dimensional shape model for Psyche was derived from an analysis of numerous light curves.

All recent models for Psyche suggest it rotates about a pole pointed towards the ecliptic coordinates (long, lat) λ = 35°, β = -8°, with a 3° uncertainty.

The largest of these are regions of mass-deficits relative to its nominal ellipsoid shape and are reminiscent of the Rheasilvia basin on 4 Vesta.

[31] However, in at least three locations, Psyche's radar albedo is nearly twice this value, suggesting high concentrations of metal phases in these regions.

[4][24][6] This apparent correlation between optical and radar albedos on Psyche has led to the hypothesis that there is a link between the process(es) that create regions of high metal content and brighter terrain.

[33][34][35] Spectra taken in October 2016 at the NASA Infrared Telescope Facility at the Mauna Kea Observatories showed evidence (~3 μm absorption feature) of hydroxyl ions on the asteroid that may suggest the presence of hydrated silicates.

[36][31] Psyche's radar albedo varies considerably over the surface, ranging from 0.22 to 0.52,[6] values that are two to four times as high as most main-belt asteroids.

The earliest of these was that Psyche is an exposed metallic core resulting from a collision that stripped away the crust and mantle of an originally larger differentiated parent body some 500 kilometers in diameter.

[39] A third hypothesis is that Psyche may be a differentiated object, like 1 Ceres and 4 Vesta, but has experienced a type of iron volcanism, also known as ferrovolcanism, while still cooling.

[41][42] A team led by Lindy Elkins-Tanton,[43] the director of the School for Earth and Space Exploration at Arizona State University, presented a concept for a robotic Psyche orbiter.

[44] The mission was approved by NASA on 4 January 2017 and was originally targeted to launch in October 2023, with an Earth gravity assist maneuver in 2024, a Mars flyby in 2025, and arriving at the asteroid in 2030.

[47] On 28 February 2020, NASA awarded SpaceX a US$117 million contract to launch the Psyche spacecraft, and two smallsat secondary missions, on a Falcon Heavy rocket.