Measurements of ion streams found to exist in the near wake of the shuttle Orbiter (Spacelab 2 mission) were used to examine the applicability of a one-dimensional, time-dependent plasma expansion model for wake filling. The results of the examinations show a good agreement between theroy and experiment. This agreement implies that the measured streams can be interpreted in terms of collisionless plasma expansion. ¿ American Geophysical Union 1989