LANL: Un-Earthing Planetary Defense

Studying extraterrestrial bodies could help defend Earth from future impact threats. Photo Courtesy LANL


This summer, NASA will launch its first mission to a metallic asteroid, 16 Psyche, located in the main asteroid belt between the orbits of Mars and Jupiter. Previous missions have explored rocky and icy asteroids, but Psyche’s composition is widely believed to consist of a considerable amount of metal. Of course, in today’s click-bait culture, googling Psyche will take you down the proverbial Internet rabbit hole of stories about how it is worth more than the global economy. As enticing as that idea is, we are not going to scrap it and sell it for parts.

From a scientific perspective, though, Psyche is priceless.

In school, we learn that Earth has a layered structure: crust, mantle, and core (inner and outer). Billions of years ago, as Earth and other planets were forming, collisions between solid bodies were more frequent than today. Some of these collisions resulted in accretion, helping to build up these layers and leading to larger solid bodies that became planets. Others resulted in disruption, in which planetesimals were blown apart before they could fully form into planets. The metallic asteroids are thought to be their remnants, cores of would-be planets that were stripped of their outer layers through high-velocity impacts.

Psyche is the largest of these remnants, with an approximate diameter of 140 miles. Psyche may hold answers to questions about the early solar system, including how planets form, or, in Psyche’s case, fail to fully form. The NASA mission will be equipped with instruments for measuring various properties of Psyche, and these data can provide more insight into the asteroid’s composition, including how much of it is metallic and how much porosity (empty space) is present.