Positioning instruments offering a submicrometric accuracy within a restricted mass budget will become indispensable in future planetary exploration missions. Among the technologies known to date, only the combination of piezoelectric actuators with capacitive displacement sensors meets such specifications. This solution has the advantages of providing a rugged, frictionless, solid-state mechanism, which can be finely controlled due to the high signal to noise ratio that can obtained with the drive electronics. This actuator-sensor combination was applied to the design of an XY stage that could offer 100 x 100 micrometer strokes in a total mass budget of 400g. Since the required stroke was too large to be achieved directly with the piezoelectric material, the amplification technique developed at Cedrat Recherche was employed. Their Amplified Piezoelectric Actuators were chosen over other techniques, such as Hertzian pivots, because of the mass requirement on the system. The design of the stage made it necessary to address issues such as the guiding functions, especially important to reduce parasitic degrees of freedom. Finite element analysis was used intensively. The engineering model built includes eight APA50S actuators and two capacitive displacement sensors. The operating performance was tested and shown to be close to the predicted results. The strokes and parasitic degrees of freedom were measured using a laser interferometer. The stage was tested over the temperature range (-20°+50°C), submitted to random vibrations tests, and its lifetime was tested over more than one million strokes. The results of these tests and other parameters, such as piezoelectric drift and gravity effects on the functional performances, are discussed. This paper focuses on the design aspects of the XY stage, the tools used for this design and the lessons learned from its development.