On 26 February 2026, the NASA/ESA/CSA James Webb Space Telescope observed the extremely faint near-Earth asteroid 2024 YR4 with its Near-Infrared Camera (NIRCam). By measuring its position against precisely catalogued background stars, astronomers ruled out an impact with the Moon on 22 December 2032.[1] The asteroid had previously carried a 4% lunar-impact probability, although its Earth-impact risk had already been eliminated.[2][3]
The observation demonstrates that lunar planetary defence depends on astrometric precision, infrared sensitivity, and coordinated international operations. Webb observations, combined with ESA Gaia star positions and analysis by ESA’s Near-Earth Object Coordination Centre and NASA’s Center for Near-Earth Object Studies, converted a residual lunar-impact uncertainty into a cleared threat.[2] For a permanent settlement, even a low-probability impact warrants monitoring because lunar infrastructure, volatile reserves, power systems, and archival habitats may be geographically concentrated and difficult to replace.
The Ark team should integrate a permanent near-Earth-object surveillance protocol linking ESA NEOCC, NASA CNEOS, Gaia-derived astrometry, JWST-class infrared assets, and future lunar observatories. Maintain impact-probability thresholds for habitat evacuation and asset hardening, archive trajectory solutions and observation histories, and assess whether lunar-based telescopes can provide earlier warning for faint objects approaching Earth-Moon space.