Does a massive crater on a weird-looking asteroid give us a way to deflect incoming asteroids?
A NASA spacecraft will depart this August on a mission to explore a metal-rich asteroid called 16 Psyche—speculated to be a highly valuable object—in an effort to determine exactly what it’s made of.
It will be NASA’s first visit to a metallic asteroid, as opposed to a rocky or icy one, though it has been studied by the Hubble Space Telescope.
16 Psyche is strange. Shaped like a potato and about 140 miles in diameter, it’s more reflective than anything else in the asteroid belt between Mars and Jupiter. So bright, in fact, that it’s presumed to be composed largely of metal‚ specifically nickel, iron or gold.
That’s prompted claims that it could be worth about $10,000 quadrillion (the global economy is worth about $84.5 trillion) and that it could be a high priority for asteroid-mining in future.
However, theory that 16 Psyche could be the remains of a planet that never made it—the leftovers of a planet core—makes it priceless to astronomers trying to figure how the Solar System formed.
Its exact composition will be for the NASA spacecraft to determine from orbit, but a large crater on its surface is already giving scientists clues—and could provide critical intelligence for future attempts deflect a rogue object.
Asteroid-deflection is something NASA is very interested in perfecting well in advance of aa large asteroid being spotted that’s heading straight for Earth. On October 22, 2022 NASA’s Double Asteroid Redirection Test (DART) will smash a 500kg spacecraft into binary asteroid 65803 Didymos and its moonlet Dimorphos (also called “Didymoon.”) The idea is that by creating a “kinetic deflection” on Dimorphos it will ever so slightly change the trajectory of both objects.
However, what happened on 16 Psyche was something altogether more violent.
The theory goes that something smashed into 16 Psyche a few billion years ago, creating a massive crater about four miles deep and 33 miles wide. Running for a few days on up to 3,000 cores of a Los Alamos supercomputer, a new visualization by Los Alamos National Laboratory simulates what happened in the 400 seconds after 16 Psyche was struck by something.
“This is a weirdly shaped crater, shallow and wide,” said Wendy K. Caldwell, applied mathematician/planetary scientist at Los Alamos National Laboratory and the lead author for Los Alamos simulations of Psyche. Caldwell presented the team’s research results at the 2021 AGU Fall Meeting.
The simulations shed some light on what, exactly, 16 Psyche might be made of—rubble. Radar observations indicate the asteroid is metallic, but density measurements indicate it is porous. “In our simulations, hexagonal packing in a rubble pile gave almost perfect matches to the ratio of the depth to the diameter on Psyche,” said Caldwell. “That result was really exciting, because it’s shape, not just size, that you have to understand to determine the feasibility of potential compositions.”
The simulation shows an impactor striking Psyche modeled as a hexagonally packed rubble pile. Square packing of the rubble pile material failed to accurately reproduce the actual crater shape observed on Psyche, but hexagonal packing was a very close match. The rubble that makes-up 16 Psyche is expected to be of varying sizes and shapes.
Operating under NASA’s Discovery program, the Psyche spacecraft will lift-off atop a SpaceX Falcon Heavy rocket in August this year. The tennis court-sized construction with have seven scientific instruments and two solar arrays pr provide power.
The Psyche spacecraft will then conduct a gravity-assist flyby of Mars in May 2023 before finally arriving at 16 Psyche in January 2026. NASA’s spacecraft will go into orbit of 16 Psyche and attempt to determine whether or not it is a planet core, map it and age it.
“The Psyche mission will help us understand more about the early days of the solar system and how the planets formed,” said Caldwell.
Wishing you clear skies and wide eyes.