A solar sailcraft is the spacecraft that uses the solar radiation pressure force for acceleration and does not need any propellant other than the sunlight. PolarBeeSail (PBS) is designed as a solar sailcraft and a nanosatellite in 4U CubeSat shape and has 4 m x 4 m solar sail providing the satellite small but reasonable thrust levels. The PBS is a science oriented spacecraft. Its main objective is to investigate the polar magnetospheric regions using a plasma analyzer and magnetometer. Its lifetime is planned as 11 years, which is equivalent to one solar cycle. In this study, mission and design of PBS are given with the basics of the solar sail concept (or solar sailing). The Earth's magnetic environment consists of various particles with different energy levels. The high energetic particles from the Sun and from other galaxies harm the spacecraft and decrease its efficiency. Among the several effects of the space environment, here we conduct a radiation analysis for PolarBeeSail, which will have a polar orbit, using the models in SPENVIS. As a result of the analysis we recommend an applicable thickness of aluminium to be used with PolarBeeSail.