© Springer-Verlag Berlin Heidelberg 2013. Dynamic two-dimensional discharge patterns on various polymeric materials under atmospheric and low pressures are carried out using a newly developed measurement system based on Pockels effect. Spacecraft in space environment are exposed to high energy particles and radio-active rays. When the high energy particles impinge onto the surfaces of spacecraft polymeric materials they are charged, bringing sometimes to surface discharges that often can cause serious accidents. Since many accidents due to such irradiation effects are reportedther is a need to investigate deeper the discharging effects on the surface of polymeric materials under low pressure. We developed a measurement system to observe the surface discharge pattern under low pressure conditions. In this experiment, the discharge is generated by applying high voltage to a needle on the material. Using the system, we observe various streamer patterns of the surfaces of investigated materials. Judging from the results, we found that there are two kinds of positive streamer patterns. By using numerically calculated ionization energies of various materials, we found that the formed patterns can be classified by the ionization energies.