The design, development and test of a fine pointing assembly (FPA) stabilising the line of sight of an optical free space data communication link between satellites is presented. The FPA is fast enough to compensate for vibrational perturbations of the platform, compact, and has low power consumption. A second FPA mounted in the optical terminal equipment allows to realise the point-ahead function required in bidirectional long distance optical intersatellite links. The FPA design is based on a 2-axes tip-tilt mirror suspended on a flexure membrane. Driven by 4 Lorentz actuators its position is sensed with differential capacitive sensors. The control electronics linearises the sensor characteristic, and implements a cascaded feedback scheme, with state space motion controllers, and transconductance current amplifiers.