■ Background and necessity
● Recently, as the military domain has expanded into space, the field of national security requires not only high-resolution image information to recognize changes in the target's location and status in a timely manner, but also periodic image information with a resolution of 1 m or less to monitor abnormal signs of the target. must be provided.
● In order to acquire image information with a resolution of 1m or less in a short period of time, at least dozens of ultra-small image information satellites in low-Earth orbit are needed.
● In order to realize at a reasonable level the enormous deployment cost of a satellite constellation consisting of dozens of ultra-small image information satellites in low-Earth orbit, consider implementing individual satellites at a low cost.
■ Research methods
● Survey of low-orbit ultra-small image information satellites by country
- Data from space development-related organizations (NASA, ESA, JAXA, etc.) by country
- Patent data related to space development by country
- Search keywords: LEO (Low Earth Orbit), Micro Satellite, SAR (Synthetic Aperture Radar), EO (Electro-Optic)
● Research low-orbit ultra-small image information satellites on space-related search portals.
- Data from satellite search portals (Gunter’s Space Page, eoPortal, etc.)
- Data from space news portals (SPACENEWS, etc.)
- Search keywords: LEO, Micro Satellite, SAR, EO
■ Research scope
● Development of low-orbit microsatellites (100kg class) capable of acquiring image information (optical sensor, SAR: Synthetic Aperture Radar, radar, etc.) with a resolution of 1m or less.
● Excluding cube (mass several kg) satellites for studying the characteristics of low-Earth orbit
● Draw implications
■ Implications
● Considering video information for monitoring abnormal signs of major targets, it is possible to capture multiple videos with a maximum resolution of 1.0m or less while maintaining an appropriate level of video quality (NESZ, PSNR: Pixel Signal Noise Ratio, MTF: Modulation Transfer Function, etc.) Development is needed to target capabilities.
● In order to extend the operational life of maintaining the mission orbit, it is reasonable to apply an electric propulsion system that can be implemented in a lightweight manner due to the high fuel propulsion efficiency.
● Considering the ease of launch and launch cost, it is cost-effective to develop a 100kg class low-orbit ultra-small image information satellite.
● It is necessary to develop a satellite constellation consisting of dozens of satellites to continuously and efficiently accumulate target information according to the shooting plan.
● In order to reduce the cost of implementing the system, it is reasonable to develop the system to meet the reliability requirements of users by increasing the reliability of the satellite group rather than the reliability of individual satellites (adding extra satellites more than the required number of satellites).
● To reduce the cost of implementing individual satellites, it is effective to actively utilize relatively low-cost/low-reliability military/civilian parts rather than expensive/high-reliability space-grade parts and to pursue single chain design of main components rather than multiple chain design of main/minor components. lim.