Scientists are raising concerns about the potential risks associated with asteroid deflection strategies. While missions like NASA’s successful DART (Double Asteroid Redirection Test) demonstrated that it’s possible to alter an asteroid’s trajectory, new findings suggest that poorly executed deflection attempts might inadvertently postpone an asteroid impact rather than prevent it.
Research from the University of Illinois reveals that inaccurately aimed asteroid deflections could direct these celestial bodies into regions of space known as “gravitational keyholes.” These areas can affect the trajectory of an asteroid, potentially leading to a collision with Earth years or decades later. The concept is likened to a pinball machine, where striking the wrong bumper sends the ball back into play in an undesired direction.
Rahil Makadia, a researcher at NASA, emphasized the importance of precision in asteroid deflection missions: “Even if we intentionally push an asteroid away from Earth with a space mission, we must ensure it doesn’t drift into one of these keyholes afterwards. Otherwise, we’d be facing the same impact threat again down the line.”
Identifying Safe Deflection Zones
To address this challenge, Makadia’s team has developed probability maps that pinpoint the safest locations for striking asteroids. Each point on an asteroid’s surface has a different likelihood of directing it toward a gravitational keyhole after being deflected by a kinetic impactor. Creating these maps necessitates a thorough understanding of the asteroid’s physical characteristics, including its shape, rotation, and mass.
Ideally, this detailed analysis would involve a dedicated space mission to observe the asteroid closely. Such missions can produce high-resolution images and data, allowing scientists to create accurate deflection strategies. However, if an asteroid is detected late, researchers can still produce preliminary maps using ground-based telescopes, albeit with lower precision.
The researchers have already established probability maps for well-known asteroids, including Bennu, with crosshairs marking optimal impact zones. These maps take into account the uncertainties inherent in any space mission, acknowledging that even the most precisely targeted spacecraft might miss its mark by several meters.
Future Missions and Planetary Defense
While the DART mission specifically targeted Dimorphos because its larger counterpart, Didymos, poses no immediate threat to Earth, future asteroid encounters may be less forgiving. Real planetary defense missions will demand meticulous planning and execution to ensure successful outcomes.
The European Space Agency’s upcoming Hera mission, scheduled to reach the DART impact site in December 2026, is expected to provide critical data that will refine these deflection techniques.
As researchers continue to monitor the sky for potential threats, the urgency for effective asteroid deflection strategies grows. Although no significant asteroid threats have been identified thus far, scientists remain vigilant. With the advancements made by Makadia and his team, humanity may be better prepared to respond when the need for planetary defense arises.
This article was originally published by Universe Today.
