Inactive space objects are usually rotating and tumbling as a result of internal or external forces. KOREASAT 1 has been inactive since 2005, and its drift trajectory has been monitored with the optical wide-field patrol network (OWL-Net). However, a quantitative analysis of KOREASAT 1 in regard to the attitude evolution has never been performed. Here, two optical tracking systems were used to acquire raw measurements to analyze the rotation period of two inactive satellites. During the optical campaign in 2013, KOREASAT 1 was observed by a 0.6 m class optical telescope operated by the Korea Astronomy and Space Science Institute (KASI). The rotation period of KOREASAT 1 was analyzed with the light curves from the photometry results. The rotation periods of the low Earth orbit (LEO) satellite ASTRO-H after break-up were detected by OWL-Net on April 7, 2016. We analyzed the magnitude variation of each satellite by differential photometry and made comparisons with the star catalog. The illumination effect caused by the phase angle between the Sun and the target satellite was corrected with the system tool kit (STK) and two line element (TLE) technique. Finally, we determined the rotation period of two inactive satellites on LEO and geostationary Earth orbit (GEO) with light curves from the photometry. The main rotation periods were determined to be 5.2 sec for ASTRO-H and 74 sec for KOREASAT 1.

1. INTRODUCTION
 2. ROTATION PERIOD OF THE LEO SATELLITE,ASTRO-H
 3. ROTATION PERIOD OF THE FIRST KOREANSPACE DEBRIS ON GEO KOREASAT 1
 4. SUMMARY
 ACKNOWLEDGMENTS
 REFERENCES

• Jin Choi(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea, University of Science and Technology, Daejeon 34113, Korea)
• Jung Hyun Jo(Korea Astronomy and Space Science Institute, Daejeon 34055, KoreaM, University of Science and Technology, Daejeon 34113, Korea)
• Myung-Jin Kim(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Dong-Goo Roh(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Sun-Youp Park(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Hee-Jae Lee(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea, Chungbuk National University, Cheongju 28644, Korea)
• Maru Park(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Young-Jun Choi(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Hong-Suh Yim(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Young-Ho Bae(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Young-Sik Park(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Sungki Cho(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea, University of Science and Technology, Daejeon 34113, Korea)
• Hong-Kyu Moon(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Eun-Jung Choi(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Hyun-Jung Jang(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Jang-Hyun Park(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)