Astronomers have identified a potential threat from asteroid 2024 YR4, which could collide with the Moon in 2032. While initial concerns about a direct impact on Earth have been dismissed, the asteroid still carries a 4% chance of hitting the lunar surface. This possibility has prompted the scientific community to consider strategies for mitigating the risk, particularly as a lunar impact could generate substantial micrometeoroid debris that may jeopardize the safety of spacecraft and astronauts aboard the International Space Station.
The findings from a recent study conducted by researchers at NASA and several U.S. institutions, submitted for peer review to the Journal of the Astronautical Sciences, outline potential responses to this scenario. The authors evaluated various methods for deflecting or destroying the asteroid before it reaches the Moon, concluding that destruction may be the most effective course of action.
Deflection Challenges
Typically, deflection is the preferred approach when dealing with potentially hazardous asteroids. However, in the case of 2024 YR4, the researchers caution that deflection could result in unpredictable outcomes. This is because successfully altering the asteroid’s trajectory requires precise calculations regarding its mass and density. Currently, estimates suggest that 2024 YR4 could weigh between 74 million pounds (approximately 33 million kilograms) and over 2 billion pounds (around 930 million kilograms), which introduces significant uncertainty.
The James Webb Space Telescope recently provided measurements indicating the asteroid’s diameter is roughly 197 feet (or 60 meters). Yet, without a clear understanding of its composition, determining its mass remains challenging. Miscalculating the required energy for deflection risks redirecting the asteroid toward Earth instead.
Given these complexities, NASA could initiate a reconnaissance mission to gather further data on 2024 YR4. However, the optimal time for such a mission would be in 2028, allowing only a narrow window of three years for development, which the researchers deemed inadequate for a successful deflection strategy.
The Case for Destruction
Faced with these significant hurdles, the researchers advocate for destruction as a more feasible solution. They propose several methods for accomplishing this. One option is a robust kinetic disruption mission, akin to NASA’s previous DART mission, but focused on breaking the asteroid apart rather than changing its course. While this method has not been tested, the timeline allows for mission development, with the next available launch window occurring between April 2030 and April 2032.
Alternatively, researchers suggest the possibility of utilizing a nuclear device to fragment 2024 YR4. Although this method has not been previously tested, it remains theoretically viable. The timing for such a mission would align with a launch window from late 2029 to late 2031.
As 2024 YR4 approaches its close pass, which is expected to be safe, the threat it poses also serves as a valuable opportunity for scientists. This period allows for the refinement of strategies aimed at preventing impacts on both Earth and the Moon, ensuring preparedness for any future threats. The scientific community remains focused on developing effective responses, underscoring the importance of vigilance in planetary defense.
