Different orbital scenarios for satellite missions are evaluated with respect to their ability to provide a satisfactory altimeter data set as input into an assimilation procedure. The assimilation is realized, using the technique of ''nudging'' (Anthes, 1974), into a numerical simulation of the general oceanic circulation at mid-latitudes involving strong variability fields of the Gulf-Stream-like jet stream. The numerical model is multilayered and quasi-geostrophic, and it considers basin-scale circulation with high resolution. The basic orbital scenarios under consideration are four in number: the two ERS 1 and Topex/Poseidon nominal mission parameters (with 3- and 10-day orbital periods, respectively) and two extra possibilities for Topex/Poseidon: a 17-day orbital period scenario (close to the Geosat parameters) and a 29-day orbital period scenario. All four cases are compared for assimilation experiments realized under identical conditions. The criterion of efficiency is to ensure that model flows converge toward observations, i.e., the fact that surface information is sufficient to recreate via the model the realistic three-dimensional ocean circulation. In the conditions of experiments, results show that the 10- to 17-day range is able to satisfy the convergence condition to some extent. This is not the case for the two scenarios outside this range. The effect of subsequent undersampling (subcycles) are examined in the 10-day case and found to be of little importance as long as sampling is sufficiently regular. Preliminary tests to take into account data and model inaccuracy are reported. ¿ American Geophysical Union 1990