This presentation forms the basis for recommending up to two mission candidates to proceed to Phase A, for the twelfth Earth Explorer mission, within the European Space Agency’s Future Earth Observation (FutureEO) Programme. It presents the Keystone mission concept, which has successfully completed its Phase 0 preparation. Keystone would explore the region of the atmosphere which goes from 50km to 250km, with a unique, ambitious and novel approach. It would deliver pioneering observations of atomic oxygen with collocated observations of other trace gases, temperature and wind, using a novel combination of limb-sounding techniques across the Terahertz, infrared and UV-visible spectral domains. By characterising this data-sparse region chemical composition and thermal balance, Keystone would significantly advance whole-atmosphere chemistry-climate system understanding and improve estimates of satellite drag.
European Space Agency (Mon,) studied this question.