ESA advances three candidates for Earth Explorer 12

The European Space Agency has selected ECO, Keystone and CryoRad for the next preparatory phase of its twelfth Earth Explorer satellite mission. The three concepts would investigate Earth’s energy imbalance, the upper atmosphere and polar ice sheets — but the decision is not approval to build all three. [1]

ESA’s Programme Board for Earth Observation considered both scientific relevance and programme requirements. Its decision followed a July consultation at which scientists scrutinised four proposals. The agency’s scientific advisory committee ranked them ECO, Keystone, CryoRad and Hydroterra+; Hydroterra+ is not advancing. That ranking does not determine the eventual winner. [1]

What the candidates would study

ECO would investigate Earth’s global energy imbalance and seek to assess the effectiveness of climate mitigation measures, according to Rene Forsberg, speaking on behalf of ESA’s Advisory Committee for Earth Observation. ESA describes the concept as extremely challenging and says it will undergo further investigation. [1]

Keystone would observe atomic oxygen alongside temperature, winds and other atmospheric constituents at altitudes of 50–250 km. Forsberg said it would provide the first global direct observations of atomic oxygen together with those measurements. ESA says the concept would also detect metal from space debris entering the atmosphere. These are proposed capabilities, not observations already achieved. [1]

CryoRad would directly measure temperatures within polar ice sheets and conditions at their base, according to ESA. The aim is to improve understanding of how ice sheets behave and, in turn, help scientists assess future global sea level. The announcement does not quantify the expected improvement. [1]