  The Laser Interferometer Space Antenna is a foreseen space-based
gravitational wave detector, which aims to detect 10^20 strains in the
frequency range from 0.1 mHz to 1 Hz. It is a triangular constellation of three
spacecraft, with equal sides of 2,5 x 10^9 m, where every spacecraft hosts a
pair of telescopes that simultaneously transmit and receive laser beams
measuring the constellation arms by heterodyning the received wavefronts with
local references. Due to the spacecraft and constellation jitters, the
interfering (received and local) wavefronts become misaligned. We investigate
analytically the coupling between misalignments and aberrations of the
interfering wavefronts and estimate the relevant contribution to the noise of
the heterodyne signal.
