An experimental investigation of the perturbations created by small conducting bodies immersed in highly rarefied plasma streams was carried out the spherical and cylindrical geometries in the plasma wind tunnell facility at Marshall Space Flight Center. These measurements, as wall as the results of previous studies conducted in that facility, were evaluated for the purpose of demonstrating the potential hazards of interference between instruments mounted on diagnostic packages. The scaling in the laboratory work is sufficiently accurate to provide a rough indication of the spatial extent and magnitude of the disturbances created by small probes of 3-6 cm in diameter mounted on board spacecraft moving at altitudes of packages and design of experiments in furture space shuttle/Spacelab missions.