  The James Webb Space Telescope was not even launched yet when the Astro2020
Decadal Survey American report recommended the development of what is now
called the Habitable World Observatory, also mentioned by the Voyage 2050
European report. This future space telescope, at 11 billions dollars and at
least 6 m diameter, should allow, around 2040, the characterization of at least
25 exoplanets similar to Earth and orbiting around main sequence stars, with
the hope of discovering one where life could have developed. This objective
represents a technological challenge since it requires the design of
spectro-imagers able to access very high contrasts (10^-8-10^-10) at low
angular separations (smaller than 100 mas). This proceeding and the talk it is
associated to address various obstacles that remain to be overcome in order to
one day allow HabWorld to reach its ultimate performance.
