EChO Design Reference Mission Document
Publication date: 18 December 2013
Authors: The EChO Study Science Team
Reference: ECHO-SRE-SA-PHASEA-010, Issue 2
A Design Reference Mission, hereafter the EChO Core Survey, has been constructed for the Exoplanet Characterisation Observatory in order to determine the mission lifetime required to fulfil the science requirements. The EChO science requirements call for the observation of at least 100 exoplanets of diverse type and environment to provide a “Chemical Census” of exoplanet atmospheres. A proportion of these are required to be observed at high signal to noise ratio to provide an Origin sample and “Rosetta Stones” giving a deeper understanding of the physics and chemistry of their atmospheres. Two target samples lists have been derived: one using catalogues of real targets as known today, and a second using a statistical approach to predict how many targets will be available by the time EChO is operational in the 2020’s. These lists have been evaluated using mission performance models to test the observing time required to fulfil the EChO Core Survey. We find that a nominal mission lifetime of four years is sufficient to fulfil the science requirements and a mission of six years will fulfil the ambitious goals for EChO. The use of separate target lists and performance models gives confidence that the Core Survey can be undertaken within the mission lifetime and that will result in a revolution in understanding the origin and evolution of planets.