ESA advances three candidates for its next Earth Explorer

ESA advanced three of four candidate missions after scientific consultation and advisory review: ECO, Keystone and CryoRad. Only one will be selected for implementation as Earth Explorer 12, with launch expected around 2036. [5] Why it matters: The choice will determine which measurement gap this mission addresses: Earth's energy imbalance, the upper atmosphere or conditions inside polar ice sheets. Each targets a different limitation in understanding environmental change. [5] Key insights: ECO would target global mean Earth Energy Imbalance, which ESA's scientific adviser described as a longstanding gap in quantifying climate change and assessing mitigation. [5] | Keystone would measure atomic oxygen alongside temperature, wind and atmospheric constituents at altitudes of 50–250 kilometres. [5] | CryoRad would directly measure temperatures and basal conditions within polar ice sheets to improve understanding of ice dynamics and future sea level. [5] | The advisory ranking placed ECO first, Keystone second, CryoRad third and Hydroterra+ fourth; the board advanced the first three. [5] Cheatsheet facts: What happened: ESA narrowed four Earth Explorer 12 concepts to ECO, Keystone and CryoRad. [5] | Why: The candidates address gaps in planetary energy accounting, upper-atmosphere observations and polar ice-sheet measurements. [5] | The catch: Advancement is not approval to fly: one mission will be selected, and ESA describes ECO as extremely challenging. [5] | What's next: ESA plans to choose one candidate before its next Council at Ministerial level; the selected mission is expected to launch around 2036. [5]