Data from a laboratory simulation of current collection by a highly biased body in a spacecraft wake are presented. Ion collection from the plasma stream is investigated for both axisymmetric and nonaxisymmetric geometries. Spatially resolved current collection data, obtained by using a segmented collector, are presented for the first time. A threshold potential for the onset of current collection exists; this threshold depends strongly on the geometry of the problem and is related directly to the details of the trajectories of the collected ions. Results from an approximate numerical model of the laboratory experiment as well as the predictions of a simplified analysis are given. The agreement of the numerical solution with the experimental data is good. ¿ American Geophysical Union 1993