A folded Cassegrain type telescope objective is nothing new, but given present advancements in optical manufacturing, a worth reconsidering.
Cutting the optical tube length in half with a flat mirror and moving the secondary to the center of primary mirror hole is not a new idea and does nothing to help manufacture and assembly. Instead making a single mirror with a binary surface, i.e. one radius at inner zone and another in outer zone, a whole world of manufacture and assembly problems can be avoided. Assembly problems would eliminate themselves, and manufacturing would get easier by making traditional manufacturing near impossible and forcing more advanced techniques.
Published 30.10.2016 by Jani Achrén, who explains more here.