The significance for basic and applied sciences of the shuttle Spacelab programme is discussed, special attention being given to the vestibular research field. The European side of the programme is based on the design of a linear accelerator integrated with the Spacelab to be used on man and animals. The American vestibular function research (v.f.r.) programme is described as originated from the previous orbital frog otolith (OFO-A) experiment. (Bracchi, Gualtierotti, Morabito & Rocca, Acta otolaryngol. (Stockh.) suppl. 334, 1975). The changes of the rate of firing of single vestibular statoreceptors in bullfrogs at rest and of their responses to centrifuge spins observed during the OFO-A experiment are briefly summarized and tentatively interpreted as due to an alteration of the mechanical transducing mechanism of the cells controlled by the efferent network and/or to a modification of a membrane adaptive process. The future experiments of the v.f.r. programme are described as directed to test these working hypotheses, by reloading the otolith membrane temporarily through centrifugation during the orbital flight and by blocking the efferent junctions reversibly by means of appropriate drugs. The time course and the characteristics of the vestibular unitary activity are to be studied after re-entry on the same receptor cells. The investigation is to be extended to the semicircular canals and vibration responding units.