Several optical monitoring strategies by a ground-based telescope to protect a Geostationary Earth Orbit (GEO) satellite from collisions with close approaching objects were investigated. Geostationary Transfer Orbit (GTO) objects, Inclined GeoSynchronous Orbit (IGSO) objects, and drifted GEO objects forced by natural perturbations are hazardous to operational GEO satellites regarding issues related to close approaches. The status of these objects was analyzed on the basis of their orbital characteristics in Two-Line Element (TLE) data from the Joint Space Operation Center (JSpOC). We confirmed the conjunction probability with all catalogued objects for the domestic operational GEO satellite, Communication, Ocean and Meteorological Satellite (COMS) using the Conjunction Analysis Tools by Analytical Graphics, Inc (AGI). The longitudinal drift rates of GeoSynchronous Orbit (GSO) objects were calculated, with an analytic method and they were confirmed using the Systems Tool Kit by AGI. The required monitoring area was determined from the expected drift duration and inclination of the simulated target. The optical monitoring strategy for the target area was analyzed through the orbit determination accuracy. For this purpose, the close approach of Russian satellite Raduga 1-7 to Korean COMS in 2011 was selected.

1. INTRODUCTION
 2. HAZARDOUS ORBIT FOR THE OPERATIONALGEO SATELLITE
 3. LONGITUDINAL DRIFT OF IGSO OBJECTS
 4.SIMULATION OF OPTICAL MONITORING FOR COMS
 5. SUMMARY AND DISCUSSION
 ACKNOWLEDGMENTS
 REFERENCES

• Jin Choi(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea, Korea University of Science and Technology, Daejeon 34113, Korea)
• Jung Hyun Jo(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea, Korea University of Science and Technology, Daejeon 34113, Korea) Corresponding Author
• Hong-Suh Yim(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Young-Jun Choi(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Maru Park(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea, Chungbuk National University, Cheongju 28644, Korea)
• Sun-Youp Park(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Young-Ho Bae(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Dong-Goo Roh(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Sungki Cho(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea, Korea University of Science and Technology, Daejeon 34113, Korea)
• Young-Sik Park(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Hyun-Jung Jang(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Ji-Hye Kim(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)
• Jang-Hyun Park(Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)