GLONASS, a satellite navigation system developed in Russia since 1976, is defunct and orbits in an unstable attitude. The satellites in these problems are not managed and there is no precise information, which can increase the risk of collisions with other space objects. In this study, detailed attitude dynamic have to be analyzed through photometry data, which requires spin period and spin axis. The light curve data is obtained by observing through the photometer at the Graz station and the power spectrum is calculated to obtain the cycle of the satellite. The geometric relationship between observer and sun is analyzed for GLONASS-50 satellite. The box-wing model is applied to obtain the phase reflection of the satellite and obtain the Irradiation of the satellite through this information. In Light Curve and Irradiation, the spin axis is calculated for each peak points with the distance square minimum technique. The spin axis of the GLONASS-50 satellite is RA = 116°, Dec = 92°.

1. INTRODUCTION
2. METHODOLOGY
    2.1 Spin Period
    2.2 Spin Axis
    2.3 Solar Radiation Force
3. DATA PROCESSING AND ANALYSIS
    3.1 Observation Data
    3.2 Spin Period
    3.3 Analysis of Spin Axis
4. CONCLUSIONS
REFERENCES

• Jeeho Lee(Korea Astronomy and Space Science Institute/Department of Astronomy & Space Science, Chungnam National University)
• Eunseo Park(Korea Astronomy and Space Science Institute) Corresponding Author
• Man-Soo Choi(Korea Astronomy and Space Science Institute)
• Daniel Kucharski(Research Associate Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin)
• Yu Yi(Department of Astronomy & Space Science, Chungnam National University)
• Jong-Uk Park(Korea Astronomy and Space Science Institute)