ESA Hera Asteroid Impact Investigation

ESA's Hera spacecraft arrives at the Didymos-Dimorphos system in November 2026, following up on NASA's DART impact that altered Dimorphos's orbit by 33 minutes. With a mass of 1,128 kilograms, Hera carries advanced instruments: a wide-angle camera, thermal infrared imager, and the PALT lidar altimeter, plus two CubeSats—Milani for mineral survey and Juventas for first-ever asteroid interior radar sounding. This mission costs 363 million euros, reflecting planetary defense's strategic value. Outperforming #3 MMX in near-term applicability, Hera will calibrate impact models by characterizing the crater size, ejecta mass, and internal structure, ensuring deflection accuracy for future threats. Cheaper than the typical rival mission at 363 million euros, Hera's detailed data are essential for international planetary defense agencies to predict outcomes confidently.