Politecnico di Milano and Georgia Tech introduce new insights into asteroid deflection
by Erica Marchand
Paris, France (SPX) Feb 21, 2025
How prepared is humanity to deflect an incoming asteroid? This question is addressed in two recent studies published in *Nature Communications*, stemming from a collaboration between Politecnico di Milano, the Georgia Institute of Technology, and other global research institutions. The studies analyze the outcomes of NASA’s DART (Double Asteroid Redirection Test) mission, which successfully impacted the asteroid Dimorphos on September 26, 2022, providing the first real-world demonstration of planetary defense techniques.
Observations from telescopes such as Hubble captured a significant amount of ejecta-debris expelled from the asteroid’s surface-offering critical insights to enhance the effectiveness of future deflection strategies.
The first study, conducted by a research team from the Department of Aerospace Science and Technology at Politecnico di Milano, was led by Professor Fabio Ferrari, with contributions from Paolo Panicucci and Carmine Giordano, in collaboration with Georgia Tech. The second study, coordinated by Georgia Tech’s Professor Masatoshi Hirabayashi, also included input from Ferrari.
“We utilized images from the Hubble Space Telescope and numerical simulations to analyze the evolution of the ejecta, successfully estimating the mass, velocity, and size of the ejected particles,” said Professor Ferrari. “Additionally, we discovered complex interactions between these particles, the asteroid system, and solar radiation pressure-where sunlight influences the trajectory of the ejecta. Understanding these dynamics is essential for designing effective planetary defense strategies.”
A key finding from Georgia Tech’s study indicates that the shape of an asteroid significantly affects ejecta behavior. Professor Hirabayashi’s research revealed that the impact and Dimorphos’ rounded surface reduced the asteroid’s momentum shift by 56% compared to scenarios where the asteroid was modeled as a flat surface. This suggests that simply increasing the size of an impactor does not necessarily translate into greater deflection.
“A larger impact sends more ejecta into space, but the asteroid’s shape alters their trajectories, reducing the efficiency of the push,” explained Professor Hirabayashi. “Deploying multiple smaller impactors could enhance deflection efficiency while optimizing operational costs and increasing tactical flexibility.”
Professor Ferrari concurred, highlighting that a deeper understanding of ejecta behavior is vital for advancing asteroid deflection techniques. “Investigating impact processes and their consequences not only improves our knowledge of asteroid characteristics and evolution but also plays a crucial role in designing effective mitigation strategies for planetary defense.”
Research Report:Morphology of ejecta features from the impact on asteroid Dimorphos
Research Report:Elliptical ejecta of asteroid Dimorphos is due to its surface curvature
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