LUVOIR is a flagship mission in preparation for the 2020 decadal survey in which Exoplanets is one of the key science program. More precisely, the LUVOIR objectives are very challenging as it will target exoEarths by direct imaging with the ultimate goal to detect spectral signatures as indicative of biological activity. In that respect, the spectral range offered by LUVOIR is rich in emblematic signatures like O2, O3, H2O, CH4, vegetation red-edge, etc ... although the optimal spectral range for this purpose is still debated in the community. While this objective is extremely appealing and motivating for the future, it comes with a long list of shortcomings that need to be addressed. On the technical side, beating down the contrast down to a level compatible with exo Earth detection is still challenging. The ground based instruments like GPI and SPHERE or the space telescopes with coronagraphic capabilities like JWST and later on WFIRST will pave the road towards very high contrast imaging. I will discuss the achieved and expected performance of these projects/missions in order to figure out the actual gain needed for LUVOIR for exoEarth imaging. Then, detection itself is only the prerequisite since we are interested in getting spectroscopy, which adds an additional complexity and contrast requirement. The second problematic is related to the availability of targets and the actual stragegy to identify the best ones is still unclear today. Finally, the very central question of remote detection of life based on the presence of molecular signatures is also an critical item to be addressed. 

The purpose of this talk is not to provide answers but first of all, to set up the context of direct imaging from ground and space as far as the next ~2 decades, and then to list the problematics to be addressed before LUVOIR can fly.