NASA's Current Asteroid Risk List and Impact Probability
NASA's Center for Near Earth Object Studies maintains the Sentry risk table, which lists asteroids with non-zero cumulative impact probability through the next century. As of the latest public data, no known asteroid above 140 meters has a Palermo Technical Impact Hazard Scale value above zero for the next 100 years, and the highest-risk object is 2024 YR4, with a cumulative probability below 0.002 percent as of the most recent update. The agency updates the table daily using orbital solutions from the Minor Planet Center and JPL Horizons, and any object that crosses Earth's orbit within 0.05 AU is flagged for continuous monitoring. NASA's Planetary Defense Coordination Office coordinates with international partners to refine trajectories and rule out false positives quickly. Learn more about the Sentry system and risk metrics on NASA's official page.
The Torino Scale and the Palermo Scale translate complex orbital uncertainties into simple risk categories for public communication, with Torino values of 1 or higher triggering media and government attention. In recent years, automated surveys such as the Catalina Sky Survey, Pan-STARRS, and the upcoming Vera C. Rubin Observatory have dramatically increased the number of known near-Earth objects, reducing the chance of an undetected impactor. NASA's Double Asteroid Redirection Test mission, which successfully altered the orbit of Dimorphos in 2022, demonstrated a kinetic impactor capability for small asteroids. The agency's next steps include the NEO Surveyor infrared space telescope, designed to find hazardous objects that ground-based telescopes miss, with launch readiness milestones tracked on the mission page.
Detection, Tracking, and Planetary Defense Missions
Global Survey Networks and Detection Rates
Ground-based telescopes in Arizona, Chile, and Hawaii currently scan the sky nightly, discovering thousands of new asteroids each year and feeding orbital data into the Minor Planet Center's public database. The Vera C. Rubin Observatory, now under construction in Chile, is expected to discover millions of new objects during its ten-year survey, including many potentially hazardous asteroids that are currently too faint or distant to track accurately. NASA and the European Space Agency share tracking data through the International Asteroid Warning Network, which coordinates follow-up observations and impact modeling across multiple agencies and private partners.
Space-based assets such as NASA's NEOWISE mission have provided infrared measurements of asteroid sizes and albedos, improving mass and density estimates used in impact risk calculations. Private companies and academic groups contribute follow-up radar observations using facilities like the Goldstone Deep Space Communications Complex and the Arecibo Observatory replacement concepts, refining orbital paths within hours of discovery. The B612 Foundation and other advocacy organizations push for dedicated funding to complete the global asteroid census, emphasizing that early detection is the single most effective factor in reducing impact risk.
Deflection Technologies and Mission Timelines
NASA's DART mission proved that a kinetic impactor can measurably change the orbit of a small moonlet, and ESA's Hera mission will conduct detailed post-impact surveys to validate models for scaling this technique to larger objects. Future concepts include gravity tractors, ion beam deflectors, and nuclear standoff detonation systems, all of which require years of warning time to be effective against larger asteroids. The effectiveness of any deflection method depends on the object's size, composition, spin state, and warning time, which is why continuous sky surveys remain the backbone of planetary defense.
What the Public Should Know About Impact Preparedness
NASA and FEMA run annual planetary defense exercises that simulate an incoming asteroid scenario, testing communication chains from detection to evacuation planning, and these exercises consistently show that early detection is the critical variable for effective response. The probability of a civilization-ending asteroid impact in any given year is extremely low, but smaller objects that can cause