Upgrade of the ATLAS Silicon Strip Detector for the LHC high luminosity phase

According to current planning a major machine upgrade of the LHC towards the so-called High Luminosity LHC (HL-LHC) is foreseen for the years around 2022/23. The upgrade plans involve an extension of the physics program by approximately another 10 years, targeting a total recorded integrated luminosity of 3000 fb-1 per experiment (CMS/ATLAS). This is to be achieved by increasing the instantaneous luminosity up to 5.1034 cm-2s-1. The machine upgrades also result in increased technical requirements for the experiments and make upgrades to their detectors indispensable. The ATLAS experiment plans to replace the whole Inner Detector by a new all-silicon tracker, the design of which is driven by the higher demands on radiation hardness and granularity to guarantee good tracking performance in an environment of extremely increased particle densities. The talk focuses on the challenges involved in the design and development towards a new Silicon micro-strip detector envisaged to replace the current ATLAS Silicon Strip (SCT) and Transition Radiation (TRT) Trackers. An overview of the ongoing work in the construction and testing of prototype detector modules and related read-out and powering electronics for the barrel part, as well as plans towards an upgrade of the SCT end-caps are presented.