For the first time, a space probe will examine a world made up mostly of metal

Scientists have already sent space probes to rocky asteroids and icy comets. But this year, for the first time, a space probe departs for a mysterious metallic world!

This year, some very exciting space missions will start. And the Psyche mission cannot go unmentioned. In August 2022, the Psyche spacecraft will take to the skies and head for the asteroid of the same name, which, seen from Earth, lurks as a mysterious hazy dot in the asteroid belt. Why this space rock has sparked the interest of researchers? Well, unlike most asteroids, Psyche isn’t made up of rock or ice, but unusually rich in metal.

Psyche

The metal-rich asteroid Psyche is a particularly large specimen. It has a diameter of no less than 210 kilometers. However, much is unknown about the asteroid. In images made by telescopes, Psyche appears as a hazy dot, which we can hardly locate from Earth. Scientists have deduced from radar data that the asteroid is somewhat shaped like a potato and that it is spinning on its side. But that’s where it ends.

Not only has this mysterious character caught the attention of researchers, but the fact that Psyche is unusually rich in metal also raises interesting questions. By analyzing the light reflected from the asteroid, scientists hypothesize that the space rock — like the Earth’s core — consists primarily of iron and nickel. One possible explanation for this is that Psyche formed early in our solar system. The asteroid may represent the exposed core of a protoplanet, which has somehow lost its rocky outer layers.

Answering questions

We may get answers in a few years. Because NASA plans to pay the special asteroid a visit. A first. Because never before has a space probe traveled to a metal world. It means that the mission will explore still unexplored territory. Not only do the researchers hope to answer the question of how Psyche once saw the light of day, the mission should also provide more insight into how our solar system used to be in childhood.

Drawing of the Psyche spacecraft that will study the asteroid of the same name. Image: NASA/JPL-Caltech/ASU

So Psyche may be able to help us answer fundamental questions about the formation of our solar system. “If it turns out to be part of a metallic core, it could be part of the very first generation of early cores in our solar system,” said Lindy Elkins-Tanton, a researcher. “However, it is still speculation. We won’t know for sure until we get there. This is really going to be a journey of discovery.”

Instruments

A major challenge during the design of the mission was choosing the right instruments. Because how do you ensure that you get the data you need if you are not sure what you are going to measure specifically? Ultimately, the team opted for a magnetometer that can measure any magnetic field. The spacecraft is also equipped with a camera to photograph and map the surface of Psyche and spectrometers to determine what the surface consists of using gamma rays and neutrons that are thrown away.

The launch

But before scientists put these instruments to work, the spacecraft has to travel another 2.4 billion kilometers. After launching from NASA’s Kennedy Space Center in August 2022, the spacecraft will skim past our nearest neighbor Mars about nine months later. The probe will use Martian gravity to propel itself toward the asteroid. Then he will settle in orbit around Psyche; first at an altitude of 700 kilometers above the surface and later descending to a height of 85 kilometers. In total, the Psyche spacecraft will spend some 21 months with the asteroid, meticulously mapping it and studying its unusual properties.

The trajectory of spacecraft Psyche as it heads for the asteroid of the same name. Image: NASA

The spacecraft is not expected to arrive at Psyche until 2026. Before that, however, the mission team will already turn on its cameras. And then we’ll finally know what that faint, hazy blob we’re now watching through our telescopes actually looks like. For the first time, then, the surface features of this strange and distant world will be revealed.

Special mission

It promises to be a special mission. Because it means that for the first time we travel to a ‘metal core’ that is usually hidden deep in Earth-like planets. For example, the Earth’s core is inaccessible and is hidden far beneath rocky mantles and crusts. But asteroid Psyche offers us a unique insight into the building blocks of planet formation and the opportunity to study a previously unexplored world.

Researchers hope the mission solves several mysteries about the asteroid: Where did it come from, what is it made of, and what does it tell us about how our solar system formed? “Humans have always been explorers,” Elkins-Tanton says. “We want to know what’s behind the next hill, apparently that’s inherent in us. At the moment we really have no idea what exactly we will find. But I expect we will be completely surprised.”