Two rockets were flown through noctilucent clouds (NLC) during the Distribution and Role of Particles in the Polar Summer Mesosphere using Coordinated Rocket, Radar, and Lidar Techniques (DROPPS) rocket experiment from And¿ya Rocket Range, Norway, in July 1999. Each rocket was equipped with three-axis, double-double, high-impedance Langmuir probes (12 probes each flight) and produced unprecedented resolution of the electric potential distribution around the rockets in and near both a weak NLC (DROPPS1) and a very strong NLC (DROPPS2). Detailed analysis of the vehicle interaction during the weak NLC encounter, in which no large geophysical electric fields were detected <Holzworth et al., 2001>, provided a basis for understanding the strong NLC encounter by DROPPS2, where geophysical electric fields reached 3 V m-1. The electric field orientation is shown to be vertically downward. In the case of the strong NLC encounter a layer of excess positive charge at the top of the layer reached a density of 2 pC m-3, deduced from the sharp field gradient. The total integrated potential drop through the NLC was 2 kV.