Ok, so the Exoplanet Characterisation Observatory (EChO) project is one of four, (out of 47), major ESA Missions shortlisted in Feb 2011, for further assessment and study (in their Medium Class Cosmic Vision program) ...
It comes down to a sub 1 metre class telescope operating in the visible - thermal infrared (9.4 to 11 micron) range, to be placed in a quasi halo orbit around the second Sun-Earth Lagrange point (L2) - 1.5 million km from Earth..Originally Posted by ESA
The Cosmic Vison programme defines the high-level scientific questions which these candidate projects should be aimed at making progress towards:
The flow-on primary mission goal is:Originally Posted by ESA
Ok, so in other words, exo-gas 'biomarkers'.Originally Posted by ESA
So, putting aside the planetary formation research goals (which as far as I'm concerned, aren't an issue), the only way I can see how this project can lead towards providing hard data in answer to the ESA Cosmic Vision ‘Life emergence’ component theme question (see above), is for there to be simultaneously, local planetary exploration aimed at discovering another instance of life in our Solar System.
And, lo and behold, item 1.3 Life and habitability in the Solar System covers it:
The JUICE mission which targets the localised exploration Jovian moons, in particular Ganymede, Europa and Callisto, was recently selected for the purpose (albeit a much larger mission, in a different category than EChO).Goal
Explore in situ the surface and subsurface of solid bodies in the Solar System most likely to host – or have hosted – life
So, the noteworthy point is that the EChO mission requires the data from direct exploration missions, in order for the EChO data to be interpretable in the context of exo-life presence/absence). Without it, the EChO data can only support more speculative hypotheses.
If the exploration mission, (in this case, JUICE), doesn’t go ahead for some reason, then I don’t see how the EChO data can be constrained sufficiently to support any meaningful exo-life conclusions.
This seems to be exactly the situation NASA finds itself in at the moment !