  The construction and general implications of a model with complete
supersymmetric unification of the Standard Model matter content, interactions
and families' replication into a single $E_{8}$ gauge superfield in ten
dimensions is presented. The gauge and extended Poincar\'e symmetries are
broken through compactification of the $\mathbb{T}^6/(\mathbb{Z}_3\times
\mathbb{Z}_3)$ orbifold with Wilson lines, which reduces the original symmetry
and matter content into those of the Standard Model plus additional heavier
states. Proton decay can be suppressed automatically while the compactification
scale may be as low as $10^9~\rm{GeV}$, so that the corresponding GUT-scale
physics may be potentially accessible and testable by future collider
measurements.
