We report the research activities of the cube satellite FITSAT-1 (NIWAKA). In this project, the first observation and the analysis of the LED light emission from the space to the ground were performed. A small cube satellite mounted LEDs (Light Emitting Diodes) is released from the ISS (International Space Station). The power density of the LED emission of 4W on the ground is about 4xl0-12 W/m2 in average, which is equivalent to the star of the 8. 5th grade in average. The frequencies of the macro pulses (10Hz) and the micro pulses (5kHz) of the LED signal, were correctly clarified using the Fourier analysis. As the optical communication experiment, the potentiality of the data transmission rate of more than 1 kbit/second was shown.