Astronomers have a narrow window in February 2026 to observe asteroid 2024 YR4 using the James Webb Space Telescope, which could raise its impact odds on the moon from 4 percent to over 30 percent. The asteroid, discovered late last year, poses risks to satellites from potential lunar debris. This observation may determine if deflection missions are needed before a 2032 collision.
Asteroid 2024 YR4, discovered at the end of last year, initially raised alarms with a 1-in-32 chance of striking Earth in 2032. Subsequent observations reduced the Earth impact probability to effectively zero, but a 4 percent chance remains for a lunar collision, potentially endangering thousands of satellites through debris.
The asteroid is currently out of view from Earth's telescopes until 2028, limiting time for deflection planning. However, the James Webb Space Telescope (JWST) offers a brief opportunity in February 2026, with viewing windows on February 18 and 26. This vantage point allows JWST to observe the faint asteroid where ground-based telescopes cannot.
Andrew Rivkin at Johns Hopkins University in Maryland emphasizes the timing: “By 2028, it would be cutting things very, very close, and so getting it in early 2026 instead gives some extra time.” Calculations by Rivkin and colleagues indicate an 80 percent chance the lunar impact risk drops below 1 percent, but a 5 percent chance it rises above 30 percent. A follow-up JWST observation is possible in 2027, though with less preparation time.
NASA researchers have explored deflection options, including nuclear detonation near the asteroid, but no actions are underway. Richard Moissl at the European Space Agency states, “We have decided to definitely wait until next year… in order to have some time available for options.” He notes no current missions are budgeted, but risks could prompt reconsideration. Rivkin adds that planetary defense for the moon remains an open question, varying by agency and private interests like satellite owners.