The Tesla turbine built originally in 1913 by Nikola Tesla is an impulse and passive turbine. These characteristics drew the attention for its potential application for space cycle thermoelectric conversion and the possibility to improve cycle efficiency. The performance of a 70-mm rotor Tesla turbine will be presented and discussed. The turbine used saturated steam as the working fluid for experiments. The pressure range considered was between 300 to 700 kPa.