KOREA GEOSTATIONARY SATELLITE PROGRAM : COMMUNICATION, OCEAN, AND METEOROLOGICAL SATELLITE(COMS)

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1 KOREA GEOSTATIONARY SATELLITE PROGRAM : COMMUNICATION, OCEAN, AND METEOROLOGICAL SATELLITE(COMS) Mi-Lim Ou, Jae-Gwang-Won, Sung-Rae Chung, Hye-Sook Lee, and Ae-Sook Suh Korea Meteorological Administration Sindaebang-dong, Dongjak-gu, Seoul , Republic of Korea ABSTRACT Recently, the domestic satellite demands have been increased in various fields in Korea. Those have been raised in the fields of not only research and development but also public and civilian services. Communication and information service demands by satellite using space technology have been steadily increased by 4% per every year in Korea since Concurrently, demands on the intensive monitoring and enhanced accuracy for severe weather events by domestic satellite have been raised because the earlier warning for hazardous weather and accurate prediction of local severe weather are limited with timely sparse data from foreign satellites. With that consensus, the multi-functional geostationary satellite program has been started in 2003 and the first Communication, Ocean, and Meteorological Satellite (COMS) is scheduled to be launched in 2008 based on the National Longterm Space Development Plan of Korea. According to the development schedule, the Critical Design Review (CDR) for COMS is scheduled in March The COMS has three payloads; one for weather observation, another for ocean observation, and the other for experimental communications in Ka-bands. COMS will provide meteorological data including Level 2 products to end-users around the world and oceanography data over the Korean peninsula. COMS is planned to operate at one of the orbital positions, E or E. For the meteorological mission, the Meteorological Imager (MI) developed by ITT is selected as a meteorological payload on COMS. MI is a multi-spectral two-axis scanning radiometer, and is capable of providing imagery and radiometric information of the Earth's surface with 5 channels - one visible channel (1km resolution) and 4 infrared channels (4km resolution). The observation of COMS is planned to perform at 3 different areas, basically, global, regional, and local areas. A global mode takes full earth disk images, the Asia and Pacific images for a regional mode, and limited areas of 1000 km x 1000 km to monitor local severe weather with high temporal resolution for a local mode. The observed images will be disseminated by HRIT and LRIT formats. The 16 meteorological products including atmospheric motion vectors, cloud information, aerosol information, and WV information are under developing. Some of the products are planned to disseminate for users in LRIT format. The ground segments for COMS are developing and will be ready for the integrated functional tests at the end of this year. In the presentation, specific information will be addressed regarding COMS program, meteorological mission, ground segment preparation, and future plan for satellite development in Korea.

2 1. Introduction A long-term plan of the National Space Program was established in 1996 and revised in 2000 to accommodate the public and civilian demand for satellite utilization and keep the continuity of satellite services. The plan prospects the details of the future space activities of Korea until 2015 and serves as a basis for space development in Korea. The Korea Meteorological Administration (KMA) has been developing the Communication, Ocean, and Meteorological Satellite (COMS) in conformity with the National Space Development Plan. The COMS program is the first geostationary satellite program with the meteorological mission in Korea. There are two geostationary satellites planned in the National Space Development Plan. The first COMS is planned to launch in June 2009, and the second one is planned in Four Ministries in Korea government are involved for COMS development. Each Ministry is responsible for individual requirements and development objectives such as the Ministry of Science and Technology (MOST) for satellite system and BUS development, Ministry of Information and Communication (MIC) for communication payload and satellite control system development, Ministry of Maritime Affaires and Fisheries (MOMAF) for ocean color sensor development, and KMA for meteorological payload development. 2. COMS Missions COMS is going to be launched with three payloads, which are operated simultaneously, aiming three major missions. The first mission is a real-time observation and early detection of severe weather phenomena from Meteorological Imager (MI), which provides observation data taking account of weather forecasting and monitoring of climate change on the geostationary orbit for the public services. The second is monitoring of marine environment ecosystem from Geostationary Ocean Color Imager (GOCI) around the Korean peninsula, and the third is the in-orbit verification of the space technology for the communication payload. Each of these missions is accomplished with a dedicated payload. MI will be procured by ITT Industry of US and GOCI will be developed by EADS Astrium of France, while the Ka-Band communication payload will be in-house development by the Electronics and Telecommunication Research Institute (ETRI) in Korea. 3. Schedule for COMS development The feasibility study for COMS has begun in 2001, and the preliminary analysis has been performed in 2002, following by the main COMS development which lasts until 2009 as shown in Figure 1. Through the feasibility study, the user s requirement, mission concept, operation concept, and performance requirement as well as cost, schedule and risk estimation have been driven. The COMS conceptual design, system requirements and the cooperation plan with foreign manufacturers have determined according to the preliminary analysis. Since the COMS program has kicked off in September 2003, the EADS Astrium of France has been selected in May 2005 as a COMS manufacturer, and several review meetings for the COMS design, performances, manufacturing as well as assembly, integration and test have been scheduled. According to the development schedule, the System Design Review was completed in August in 2005, Preliminary Design Review (PDR) in January 2006, and Critical Design Review in March Figure 1 shows the major COMS milestone for development. At the end of 2006, the launcher has been selected as the Ariane 5 which has a dual launch configuration for COMS to locate at the lower position. The launch site is Guiana Space Center in Kourou.

3 Feasibility Study User Requirement Establishment COMS-I System Design Assembly, Integration, Test Launch IOT Kick Off SDR PDR CDR Launch COMS Operation and Service COMS-II Feasibility Study User Requirement Establishment Figure 1: Milestone for COMS program 4. COMS Systems Figure 2: COMS configuration Figure 2 shows the COMS configuration. There are three payloads as MI, GOCI, a communication payload, and single solar array. There is no sail for balance and it is balanced by suitable arrangement of payloads and bus system. The major COMS system requirements are summarized in Table 1. COMS is a geosynchronous and three-axis stabilized satellite. Its dry mass is estimated 2500 kg with 3 kw of electrical power. The expected operation life is more than 7 years with 75 percent reliability at the end of the life. The three payloads loaded on COMS are requested to be operable simultaneously without any interference and performance degradation. The observed

4 images and processed meteorological data are going to be distributed to users basically through direct readout with the HRIT/LRIT format within 15 minutes after the image acquisition. The MI data will be distributed with various methods which are defined later. Table 1: COMS system requirements Contents Requirements Size Weight Power Orbital location Lifetime Spacecraft stabilization Stationkeeping accuracy Reliability Payload MET data format & distribution 2.4 m x 2.4 m x 2.6 m 2500 kg 3 kw Geosynchronous at E or E with approval of ITU More than 7 years for operation More than 10 years for design life 3-axis stabilization ±0.05 in lon/lat More than 0.75 for Mi and GOCI at the end of life More than 0.85 for Communication payload MI, GOCI, Comm. Payloads operable simultaneously without interference and performance degradation HRIT/LRIT within 15 min. after image acquisition 5. Characteristics of Meteorological Imager (MI) MI is a 5-channel Imager, which includes one visible channel with 1-km spacing and four infrared channels with 4-km spacing (Table 2). To perform the meteorological mission as best, several observation modes are planned to monitor the weather phenomena around the Korean peninsula at least four times per hour. There are five observation modes covering full disk, three regional areas and locally limited area as shown in Figure 3. Especially, the local area mode will be operated under any urgent situation to focus on the area of 1000 km x 1000 km around the Korean peninsula. Table 2: Spectral channel characteristics of MI including central wavelength, bandwidth, dynamic range, and IFOV of the channels Channel no. Channel Center( μm ) Bandwidth( μm ) IFOV(km) 1 VIS ~ SWIR ~ WV ~ WIN ~ WIN ~12.5 4

5 Full Disk APNH LSH Figure 3: COMS provisional observation plan and corresponding nominal observation schedule (: Full Disk, APNH: Asia-Pacific Northern Hemisphere, : Extended Northern, LSH: Limited Southern Hemisphere, LA: Local Area) 6. COMS Ground Segment The COMS ground segment (GS) consists of four ground centers: Satellite Control Center (SOC), Meteorological Satellite Center (MSC), Korea Ocean Satellite Center (KOSC), and Communication Test Earth Station (CTES). Figure 4 shows the architecture of the COMS GS and their functions. The SOC provides the functionalities for mission operation and satellite control. It also performs MI/GOCI data processing as a hot backup basis for MSC and KOSC. MSC is the primary data processing center for MI data. MSC performs data acquisition, data preprocessing to correct radiometric/geometric errors, data distribution, and extracting meteorological products from preprocessed MI 1B data. The MI 1B data and extracted meteorological products are disseminated to users in LRIT/HRIT data format through satellite. MSC has the satellite ground control function as a backup in case of emergency situation occurred at SOC. KOSC is the primary data processing center for GOCI data. It has similar functions as MSC except for data dissemination via satellite operationally. KOSC is responsible for distribution of the GOCI L1B data and the processed products. Currently, GOCI L2 products plan to disseminate through MSC LHGS (LRIT/HRIT Generation and Transmission) system by LRIT format. The CTES will monitor RF signals to check the status of Ka-Band communication system.

6 KMA is responsible for MI mission operation after launch. In order to perform the mission, KMA has been establishing a new MSC building at Jincheon. One section of the building has been constructed for installation of the GS systems this year. At the end of 2007, the GS system at MSC will be ready for full functional test between SOC and MSC. COMS Ka-band Communication Control GOCI Sensor data TM/TC HRIT/LRIT MI Sensor data MI/GOCI Sensor data TM/TC HRIT/LRIT Korea Ocean Satellite Center (KOSC: KORDI) Meteorological Satellite Center (MSC: KMA) Satellite Operation Center (SOC: KARI) Communication Test Earth Station (CTES: ETRI) Image Data Acquisition & Control System (IDACS) GOCI - Raw Data Reception - Radiometric/Geometric Correction Image Data Acquisition & Control System (IDACS) MI - Raw Data Reception - Radiometric/Geometric Correction - LRIT/HRIT Generation & Transmission Satellite Ground Control System (SGCS) - Tracking, Telemetry, & Commanding - S/C operation - Mission planning - Orbit determination - Satellite simulation - Satellite communication - Ka-band communication payload monitoring & control GOCI Data Processing System (GDPS) - GOCI Level 2 products generation COMS Meteorological Data Processing System (CMDPS) - MI Level 2 products generation Satellite Ground Control System (SGCS) (Backup) - Same functions with SGCS at SOC Image Data Acquisition & Control System (IDACS) (Backup) MI & GOCI - Raw Data Reception - Radiometric/Geometric Correction - LRIT/HRIT Generation & Transmission Figure 4: COMS ground segment architecture and their systems Primary Backup 7. COMS Meteorological Data Processing System (CMDPS) With the development of the COMS system, KMA has been focusing its effort on utilizing various satellite data from COMS and foreign satellites. For the purposes, CMDPS has been developing within the frame of COMS program. The major functions of the CMDPS are extraction of 16- meteorological products from the calibrated and geo-located L1B data, and development of calibration algorithms to produce calibration coefficients for VIS and to monitor the IR calibration. There are 16- baseline products developed as shown in Figure 5. The product chains are aligned mainly according to priority of product sequences, time limit for operation, and interaction between the products In the CMDPS milestone, the conceptual design has been prepared in the first project year, which is based on the algorithm development strategy, annual progress, integration/optimization strategy, implementation of CMDPS in the COMS operation system, and preparation for operation. During the fourth project year of , standardization of the prototype S/W modules has been completed with the detailed interface design between the modules and MSC GS system. In present, the interface is under development and the functional test of the integrated CMDPS will be performed during this year.

7 OLR y COMS Level 1B Auxiliary Data Image data Detection Snow/Sea Ice Detection Aerosol Detection Clear Phase COD Amount AOD SST LST AMV CTT & CTH Type Insolation TPW UTH RI Fog CSR AMV : Atmospheric Motion Vector AOD : Aerosol Optical Depth COD : Optical Depth CSR : Clear Sky Radiance CTT : Top Temp. CTH : Top Height LST : Land Surface Temp. OLR : Outgoing Longwave Radiation RI : Rainfall Intensity SST : Sea Surface Temperature TPW : Total Precipitation Water UTH : Upper Tropospheric Humidity Figure 5: Flow chart of the CMDPS 16-baseline products 8. Summary and future plan The first geostationary satellite with a pure civilian purpose, COMS has been developing in Korea and is scheduled to launch in Multi-missions of COMS are intended as not only meteorological and oceanic observation for the public welfare, but also in-orbit test of the developed communication payload to be used for the next geostationary satellite. The assembly and integration for COMS has been started in September 2007 and will complete in early MI will be delivered for integration in early It is anticipated that COMS contributes as a part of the space-based Global Observing System (GOS), and the COMS data are utilized for weather monitoring, climate change monitoring, and so on.