0820026

We propose to spend four fixed-time orbits of INTEGRAL (475 000s + 475 000s) to observe the galactic microquasar SS433 which fully cover two orbital hard-X-eay eclipses near the face-on disk precessional phase of the source in April 2011 and October 2011. AO8 is exceptional for SS433 observations in comparison to all prevous INTEGRAL AOs in providing the rare opportunity to see two precessional maxima within visibility constraints of INTEGRAL and we propose to make use of this opportunity. The main scientific goal of new observations is to carry out hard X-ray spectroscopy of the source during the primary eclispe ingress/egress and to study its highly variable form.The phase-resolved spectroscopy will be used to probe the structure and physical parameters of a 20-keV rarefied corona around the center of the supercritical accretion disk in SS433 discovered in previous INTEGRAL observations. Adding new hard X-ray light curves of the primary eclipse near the precessional maximum will significantly improve upon the geometrical model of the source and the binary system parameters. The proposal is not associated with any of the AO8 Key Programs. [truncated! Please see actual data for full text]