  We report on the development of the LISA Technology Package (LTP) experiment
that will fly on board the LISA Pathfinder mission of the European Space Agency
in 2008. We first summarize the science rationale of the experiment aimed at
showing the operational feasibility of the so called Transverse-Traceless
coordinate frame within the accuracy needed for LISA. We then show briefly the
basic features of the instrument and we finally discuss its projected
sensitivity and the extrapolation of its results to LISA.
