  This document describes the technical layout and the expected performance of
the Straw Tube Tracker (STT), the main tracking detector of the PANDA target
spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner
tracking and is followed in beam direction by a set of GEM-stations. The tasks
of the STT are the measurement of the particle momentum from the reconstructed
trajectory and the measurement of the specific energy-loss for a particle
identification. Dedicated simulations with full analysis studies of certain
proton-antiproton reactions, identified as being benchmark tests for the whole
PANDA scientific program, have been performed to test the STT layout and
performance. The results are presented, and the time lines to construct the STT
are described.
