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+# ESA Hera
+
+**Type:** Planetary defense validation mission  
+**Launch:** October 2024 (Falcon 9)  
+**Target:** Didymos binary asteroid system  
+**Arrival:** November 2026 (one month ahead of schedule)  
+**Status:** En route after Mars swingby
+
+## Mission Profile
+
+Hera is ESA's follow-up mission to NASA's DART kinetic impactor test. After launching in October 2024, Hera performed a Mars swingby with Deimos flyby in March 2025. Second deep-space maneuver completed March 2026 (123 kg hydrazine, 367 m/s delta-v). Mission efficiency gains enabled one-month early arrival.
+
+## Primary Objectives
+
+1. **Crater characterization** — High-resolution survey of DART impact site on Dimorphos
+2. **Mass determination** — Precise measurement enabling accurate β factor recalculation
+3. **Internal structure** — Determine if Dimorphos is rubble pile throughout or has coherent core
+4. **CubeSat deployment** — Milani (surface mineralogy) and Juventas (internal radar sounding)
+
+## Planetary Defense Significance
+
+Hera's characterization of Dimorphos internal structure will determine whether kinetic deflection is reliable for the full potentially hazardous asteroid population or limited to rubble-pile aggregates. DART's β=3.61 likely resulted from loose structure allowing free ejecta escape. More coherent asteroids would show β approaching 1 (no momentum amplification).
+
+## Timeline
+
+- **2024-10** — Launch on Falcon 9
+- **2025-03** — Mars swingby with Deimos flyby
+- **2026-03** — Second deep-space maneuver (123 kg hydrazine, 367 m/s)
+- **2026-11** — Didymos arrival (one month ahead of baseline schedule)
+
+## Related Programs
+
+- NASA DART (kinetic impactor, September 2022)
+- China kinetic impactor test (2026)
+
+---
+
+*Mission validates planetary defense capability and determines generalizability of kinetic deflection technique across asteroid population.*
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