An Asteroid Could Approach the Moon in 2032: Why Disruption is Favored Over Deflection
A newly identified asteroid, designated 2024 YR4, presents a potential impact risk to the Moon in 2032.While a collision with Earth is unlikely, scientists are evaluating strategies to mitigate the risk of a lunar impact, and current analysis suggests that disrupting the asteroid is a more practical approach than attempting to deflect it.
The primary challenge with deflection lies in the precision required and the limited understanding of the asteroid’s characteristics. Successfully altering 2024 YR4’s trajectory demands accurate knowledge of its mass to calculate the necessary energy for course correction. Current estimates place the asteroid’s mass anywhere from 74 million pounds (33 million kilograms) to over 2 billion pounds (930 million kilograms). This important uncertainty introduces the risk of inadvertently directing the asteroid towards Earth if the deflection force is miscalculated.
NASA demonstrated a kinetic impactor deflection technique with the triumphant DART mission in 2022, ramming into the asteroid moonlet Dimorphos. However,applying this method to 2024 YR4 is elaborate by the short timeframe and the need for precise mass calculations. A reconnaissance mission to better determine the asteroid’s mass is possible, but the optimal launch window wouldn’t occur until 2028, leaving only three years to develop and deploy the mission – an exceptionally tight schedule. Researchers have concluded that deflection missions are currently impractical for preventing a lunar impact.
Given these hurdles, researchers are leaning towards a disruption strategy. Two potential methods are being considered.The first is a kinetic disruption mission, involving a spacecraft impact designed to break the asteroid apart, a technique that has not yet been tested. A launch window for this approach is available between April 2030 and April 2032.
The second, more direct option, involves detonating a nuclear device on, near, or beneath the asteroid’s surface to fragment it. while also untested, this method is considered theoretically feasible, with a launch window between late 2029 and late 2031.
Despite the potential for impact, current projections suggest 2024 YR4 will likely pass safely by the Moon. Still, this event provides a valuable possibility to develop and refine planetary defense strategies, preparing for future threats to both Earth and its natural satellite. The asteroid was measured to be approximately 197 feet (60 meters) in diameter by the James Webb Space Telescope in March.
