NASA’s Double Asteroid Redirection Test, or DART mission, which successfully impacted the asteroid Dimorphos on September 26, 2022, has provided valuable insights into an asteroid impact defense strategy for Earth. Now, a new study has used those findings to map out possible trajectories of ejecta that could be created should humanity ever need to ‘kill’ any more asteroids.
The European team of astronomers and scientists used complex computer simulations to map out the path of the ejecta and found that all that asteroid debris could potentially reach Mars and Earth, possibly creating a whole new set of problems.
NASA’s DART mission aimed to test the effectiveness of the “kinetic impact” technique for deflecting potentially hazardous asteroids. In simple terms, the science and art of ramming into an asteroid with a spacecraft.
The mission targeted Dimorphos, the more minor member of the binary asteroid system Didymos. It successfully altered its orbit by crashing a spacecraft into it at a speed of approximately 6.1 kilometers per second. While Dimorphos posed no direct or immediate threat to Earth, its size and distance made it a solid choice for a test.
The impact, which occurred 11 million kilometers from Earth, was a milestone in planetary defense research and demonstrated that if Earth were ever in the path of a giant space rock, we would know how to alter its path.
Now, some researchers have turned to the obvious ramifications of such a mission. Killing an asteroid or even trying to move it a little bit creates a lot of debris.
Utilizing advanced numerical simulations to model the behavior of the ejecta released from the DART impact, the researchers were able to map out how this ejecta would spread out from its source point, in this case, Dimorphos. They considered factors such as the ejecta’s initial velocity, size distribution, and the gravitational influence of various celestial bodies.
The simulations, which spanned a 100-year period, revealed that some of the 3 million little pieces of debris created by the DART mission could reach the vicinity of Mars within 7 to 13 years, depending on their initial velocities. Particles ejected at speeds around 770 meters per second were found to have the potential to reach Mars’ Hill sphere, a region of gravitational influence, in approximately 7 years. The study also suggested that debris traveling at velocities above 1.5 kilometers per second could reach the Earth-Moon system’s Hill sphere within roughly 7 years.
The findings of this study have significant implications for our understanding of asteroid deflection techniques and their potential consequences. While the DART mission demonstrated our ability to alter an asteroid’s trajectory, this latest study highlights the importance of considering the fate of the ejecta produced by such impacts.
According to the study, in the case of the DART mission, the size of each piece of debris is fairly harmless to those of us living on the planet, as it would burn up in the atmosphere. However, countless tiny space rocks could do serious damage to our satellites or other spacecraft in orbit.
The possibility of debris reaching the vicinity of Mars and Earth raises questions about the potential risks associated with asteroid deflection missions. It underscores the need for careful planning and risk assessment when designing future planetary defense strategies. In other words, we not only have to move an asteroid to stay safe, but we also need to map out the aftermath of the “kinetic impact.”
Another possibility is that the ejecta could potentially form a new meteor shower.
“Nevertheless, ongoing meteor observation campaigns will be critical in determining whether DART has created a new (and human-created) meteor shower: the Dimorphids,” explained study co-author Dr. Eloy Peña-Asensio, a research fellow with the DART mission from the Polytechnic Institute of Milan in a statement to Universe Today. “Meteor observing campaigns in the coming decades will have the last word. If these ejected Dimorphos fragments reach Earth, they will not pose any risk. Their small size and high speed will cause them to disintegrate in the atmosphere, creating a beautiful luminous streak in the sky.”
The DART mission was a smashing success, and a necessary step forward in our efforts to protect Earth from the threat of asteroid impacts. However, as this new study points out, the future not only has dodging giant space rocks, but lots of small ones too.
“There is probably no other impact on a planetary scale with that much information about the impactor, the target, and the ejecta formation and early development,” Peña-Asensio says. “This allows us to test and improve our models and scaling laws of the impact process and ejecta evolution. Those data provide the input data used by the ejecta evolution models.”
By studying such factors now, we may hope to reduce the potential for surprise and the risks associated with any future asteroid redirection or killing missions, should they ever become warranted in order to protect life on Earth.
MJ Banias covers space, security, and technology with The Debrief. You can email him at mj@thedebrief.org or follow him on Twitter @mjbanias.