  SS433 is the only Galactic binary system known to persistently accrete at
highly super-critical (or hyper-critical) rates, similar to those in tidal
disruption events, and likely needed to explain the rapid growth of those very
high redshift quasars containing massive SMBHs. Probing the inner regions of
SS433 in the X-rays is crucial to understanding this system, and super-critical
accretion in general, but is highly challenging due to obscuration by the
surrounding wind, driven from the accretion flow. NuSTAR observed SS433 in the
hard X-ray band across multiple phases of its 162 day super-orbital precession
period. Spectral-timing tools allow us to infer that the hard X-ray emission
from the inner regions is likely being scattered towards us by the walls of the
wind-cone. By comparing to numerical models, we determine an intrinsic X-ray
luminosity of $\ge$ 2$\times$10$^{37}$ erg/s and that, if viewed face on, we
would infer an apparent luminosity of $>$ 1$\times$10$^{39}$ erg/s, confirming
SS433's long-suspected nature as an ultraluminous X-ray source (ULX). We
present the discovery of a narrow, $\sim 100$s lag due to atomic processes
occurring in outflowing material travelling at least 0.14-0.29c, which matches
absorption lines seen in ULXs and -- in the future -- will allow us to map a
super-critical outflow for the first time.
