The ASTENA mission concept consists of a broad band Wide Field Monitor Imager and Spectrometer and a broad band Narrow Field Telescope. The latter is a Laue lens (∼3 m diameter, 20 m focal length) sensitive to the 50 – 600 keV energy pass-band made of Silicon and Germanium cylindrical bent crystals. Such crystals allow the radiation to be focused into a narrow point spread function never achieved so far. In the presented configuration the instrument field of view is ∼ 4 arcmin with angular resolution of ∼30 arcsec. The Laue lens is coupled with a high efficiency (>80% above 600 keV) focal plane position sensitive detector, with 3D spatial resolution of 300 μm in the (X,Y) plane, fine spectroscopic response (1% at 511 keV) and polarization sensitivity. In this paper we present an overview on the satellite configuration and we mainly focus on the Narrow Field Telescope design and performances estimated with Monte Carlo simulations.