On September 26, 2022, NASA’s Double Asteroid Redirection Test (DART) mission collided with Dimorphos, a small moon orbiting the larger asteroid Didymos, successfully demonstrating the mission’s proposed strategy for deflecting potentially hazardous asteroids (PHAs)—the kinetic impactor method.

By October 2026, ESA’s Hera mission will rendezvous with the binary asteroid system and conduct a detailed post-impact study of Dimorphos to ensure that this planetary defence method can be replicated in the future. However, the kinetic method can successfully repel asteroids that threaten Earth, while also creating debris that can reach Earth and other celestial bodies.

In a recent study, an international team of scientists investigated how this impact test also provided an opportunity to observe how this debris could one day reach Earth and Mars in the form of meteors. After running a series of dynamic simulations, they concluded that an asteroid impact could reach Mars and the Earth-Moon system within a decade.

The research team was led by Dr. Eloy Pena-Asensio, a researcher in the Deep Space Astrodynamics Research and Technologies (DART) group at the Polytechnic Institute of Milan.

He was joined by colleagues from the Autonomous University of Barcelona, ​​the Institute of Space Sciences (ICE-CSIS), part of the Spanish National Research Council, the Catalan Institute for Space Studies (IEEC) and the European Space Agency (ESA).

A paper detailing the results of the research was recently published online and accepted for publication by The Planetary Science Journal.

For their study, Pena-Asensio and colleagues relied on data from the Italian Light Asteroid Imaging Satellite (LICIACube), which accompanied the DART mission and witnessed the kinetic impact test.

This data allowed the team to constrain the launch’s initial conditions, including their trajectory and speed, from a few tens of meters per second to about 500 m/s (1,800 km/h; ~1,120 mph). The team then used supercomputers at NASA’s Navigation and Support Information Center (NAIF) to simulate what would happen to the launch.

These simulations tracked the 3 million particles produced by the DART mission’s collision with Dimorphos. As Pena-Asensio told Universe Today via email:

“LICIACube provided important data on the shape and orientation of the ejection cone immediately following impact.

“In our simulation, particle sizes ranged from 10 centimeters to 30 micrometers; the lower range represents the smallest sizes that could produce meteors observed on Earth with current technology. The upper range was limited by the fact that only centimeter-sized ejecta were observed.”

The results of the study showed that some of these particles would reach Earth and Mars within a decade or more, depending on how fast they were moving after the collision.

For example, particles ejected at speeds of less than 500 m/s could reach Mars in about 13 years, while particles ejected at speeds greater than 1.5 km/s (5,400 km/h; 3,355 mph) would reach Earth in seven years. However, their simulations showed that it would probably take up to 30 years for these particles to be seen on Earth.

“But based on previous observations, these faster particles are expected to be too small to form visible meteors,” says Pena-Asensio.

“However, ongoing meteor-watching campaigns will be critical in determining whether DART has produced a new (and man-made) meteor shower, the Dimorphids. Meteor-watching campaigns in the coming years will have the final say.

“These ejected Dimorph fragments will not pose any danger if they reach Earth. Their small size and high speed will cause them to break up in the atmosphere, creating a beautiful streak of light in the sky.”

Pena-Asensio and colleagues also note that future Mars observation missions will have the opportunity to see meteors on Mars as pieces of Didymos burn up in its atmosphere.

Meanwhile, their research has also revealed the potential characteristics of these and other meteors burning up in our atmosphere in the future. This includes the direction, speed, and time of year they will be coming from, allowing any “Dimorphid” to be clearly identified. This is part of what makes the DART mission and companion missions unique.

In addition to testing an important planetary defense strategy, DART also provided the opportunity to model how emissions from the collisions might one day reach Earth and other bodies in the Solar System. As Michael Küppers, project scientist on ESA’s Hera mission and co-author of the paper, told Universe Today via email, “DART is a unique opportunity to simulate collisions between Earth and other solar system bodies:

“A unique aspect of the DART mission is that it is a controlled impact experiment, that is, a collision in which the impactor’s properties (size, shape, mass, velocity) are precisely known.

Thanks to the Hera mission, we will have good knowledge of the target’s characteristics, including the characteristics of the DART landing site. Data on the launch came from LICIACube and from ground observations after the impact.

“There is probably no other planetary-scale collision that contains so much information about the impactor, target, and footstone formation and early evolution. This allows us to test and improve our models and scaling laws for the collision process and footstone evolution. These data provide the inputs (source location, size, and velocity distribution) used in models of footstone evolution.”