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An electronic optical camera (EOC) is installed in the earth observation satellite, which records the visible ray spectrum that can be seem with the naked eye.
Based on the technology acquired from the development of Korea Multi-Purpose Satellites Arirang 1 and 2, KARI independently developed the world-class electronic optical payload AEISS (Advanced Earth Imaging System) and AEISS-A (Advanced Earth Imaging System-A). AEISS and AEISS-A were installed in Arirang 3 and 3A, respectively.
The AEISS installed in Arirang 3 is a 70cm resolution electronic optical camera, which means that it can accurately identify a car driving on the ground while flying at 7km/s at an altitude of around 700km, which is roughly the distance between Pyeongyang and Jeju Island. For a commercial purpose observation satellite, its performance is among the world's top 5.
With the exception of certain parts, AEISS was developed with Korean technology from the design phase to precise assembly, alignment and testing, as well as the final verification test in the space environment.
Since a high performance camera like AEISS cannot be developed through technology transfer or joint development, it is a technology that must be permanently available in house for the continuous development of high-performance earth observation satellites.
The development process is also very complex. First of all, ultra-precision technology to the level of 1/5000 of a human hair is needed for the assembly of an optical system such as the reflector. Moreover, even micro-vibrations generated by a human or vehicle near a building can cause a measurement error. Such an ultrasensitive device must be operated for 3~7 years under vacuum conditions and a temperature difference of more than 100℃ after withstanding a launch environment with tens of times gravity. That is why only a few counties such as the US, Russia and France have been able to develop a state-of-the-art satellite electronic optical camera such as AEISS.
AEISS-A is the follow-up model of AEISS developed by KARI. Its optical resolution is 55cm, and it is equipped with an IR sensor to enable nighttime photography and heat sensing. To achieve this, the electronic module of AEISS was upgraded, and the IR channel developed in Korea was added to it. The higher resolution was obtained by solving the problems of shorter camera exposure time and undesirable noise signals caused by lowering the altitude from 685km to 528km.
KARI plans to continue developing original payload technologies including key parts.