What Will Psyche Do?

The Psyche spacecraft launched Oct. 13, 2023, at 10:19 a.m. EDT from Kennedy Space Center. Psyche lifted off from Launch Pad 39A aboard a SpaceX Falcon Heavy rocket. Psyche was the first in a series of NASA science missions to be the primary payloads launched on a SpaceX Falcon Heavy rocket.

The spacecraft separated from its rocket about an hour after launch, and around the 90-minute mark established two-way communication with NASA’s Deep Space Network complex in Canberra, Australia, at 11:50 a.m. EDT.

Asteroid Psyche’s gravity will capture the spacecraft in late July 2029, and Psyche will begin its prime mission in August. It will spend about two years orbiting the asteroid to take pictures, map the surface, and collect data to determine Psyche’s composition. 

The body of the Psyche spacecraft is about the size of a small van, and it’s powered by solar electric propulsion. It has a magnetometer, a gamma-ray and neutron spectrometer, and a multispectral imager to study asteroid Psyche. The spacecraft will start sending images to Earth as soon as it spots the asteroid. 

If it is a planetesimal, asteroid Psyche may offer a close look at the interior of terrestrial planets like Earth. We can’t bore a path to Earth’s metal core – or the cores of the other rocky planets – so visiting Psyche could provide a one-of-a-kind window into the violent history of collisions and accumulation of matter that created planets like our own.

Scientists think asteroid Psyche, which is about 173 miles (280 kilometers) at its widest point, could be part or all of the iron-rich core of a planetesimal, a building block of a rocky planet.

The asteroid also could also be something else. It could be the leftover piece of a completely different kind of iron-rich body that formed from metal-rich material somewhere in the solar system. Psyche may be able to show us how Earth’s core and the cores of the other terrestrial planets came to be.

The Journey to Asteroid Psyche

The Psyche spacecraft’s voyage to its namesake asteroid could (almost) be considered a journey to the center of the Earth. Asteroid Psyche might be an exposed core of a planetesimal, an early planetary building block. It might have been stripped of its outer layers by violent collisions during our solar system’s early formation.

About Asteroid Psyche

Psyche was discovered in 1852 by Italian astronomer Annibale de Gasparis. Because it was the 16th asteroid to be discovered, it is sometimes referred to as 16 Psyche. It’s named for the goddess of the soul in ancient Greek mythology, often depicted as a butterfly-winged female figure.

Psyche orbits the Sun in the outer part of the main asteroid belt between Mars and Jupiter. It is approximately three times farther from the Sun than Earth. Because Psyche and Earth orbit at different speeds, the distance from Earth to Psyche varies from less than 186 million miles to more than 372 million miles.

Psyche is irregular and potato-like. If the asteroid were sliced in half horizontally at the equator – picture a squished oval – it would measure 173 miles (280 kilometers) across at its widest point and 144 miles (232 kilometers) long. Its surface area is 64,000 square miles (165,800 square kilometers).

Psyche is dense, estimated at about 212 to 256 pounds per cubic foot (3,400 to 4,100 kilograms per cubic meter). The surface gravity on Psyche is much less than it is on Earth – even less than it is on Earth’s Moon. On Psyche, lifting a car would feel like lifting a large dog. 

Scientists think Psyche may consist of significant amounts of metal from the core of a planetesimal, one of the building blocks of our solar system. The asteroid is most likely a survivor of multiple violent hit-and-run collisions, common when the solar system was forming. 

There are still contradictions in the data, but scientific analysis indicates that Psyche is likely made of a mixture of rock and metal, with metal composing 30% to 60% of its volume. The asteroid’s composition has been determined by radar observations and by the measurements of the asteroid’s thermal inertia (how quickly an object gains or re-radiates heat). 

By combining radar and optical observations, scientists have generated a 3D model of Psyche that shows evidence of two craterlike depressions. It suggests that there is significant variation in the metal content and color of the asteroid over its surface. But until this mission sees the asteroid Psyche up close for the first time, we don’t know what it actually looks like.