In recent years, nano satellite has gained popularity among students and young researchers. The reason is that, nano satellite has the ability similar to larger satellite, but in tiny compact size. It is easy to made and can be made using low cost devices. However the main problem in making a nano satellite is in the its communication system. Nano satellite communication system has to be reliable to send information from ground station to nano satellite or vice versa. In this paper, we propose a nano satellite communication system using Raspberry Pi, and a HackRF SDR which is programmed using GNURadio. From the testing process, the text data can be transmitted properly from ground station to nano satellite using GMSK modulation scheme. This communication system also has ability to be reconfigured, which means many modulation scheme and algorithm can be implemented easily without changing the hardware.