This article explores brief overview of modern radar systems for imaging and monitoring the Earth from space. The operating radar systems are divided into four classes: large spacecraft with global monitoring SAR, medium-sized spacecraft with detailed observation SAR, small spacecraft with detailed observation SAR, and commercial mini-spacecraft with detailed observation SAR. Listed are the main representatives of each class. Such large satellites as: European – Sentinel-1 (A, B); Japanese – ALOS-2; Canadian company MDA – Radarsat-2; Argentine – SAOCOM-1A / 1B; Chinese – Gaofen-3. Representatives of the class of mid-size spacecraft with SAR: German Aerospace Center (DLR) and the leading European space company Airbus DS – TerraSAR-X, TanDEM-X; Spanish PAZ; the Italian constellation of Cosmo-SkyMed satellites of the first and second generation; Japanese group IGS-Radar; Korean – KOMPSAT-5; Russian satellites “Kondor”. The small class includes Israeli mission satellites – TecSAR, RISAT-2 (India), Ofeq-10; Japanese – ASNARO-2, German satellites SAR-Lupe, English – NovaSAR-1. The last class of mini-spacecraft includes American - Capella and Finnish – ICEYE. The article also presents spacecraft for radar imaging, planned for launch, namely: the second generation of Italian satellites COSMO-SkyMed – CSG-2; 8 ICEYE spacecrafts (Finland); an increase in the Capella constellation, X-band radar satellites of the SuperView constellation and radar satellites Zhuhai (China); ALOS-4 JAXA (Japan); KOMPSAT-6 (Korea), radar satellites of the IRS constellation (India), American satellites XpressSAR, PredaSAR, EOS SAR, satellites of the Russian design Obzor-R1 and KondorFKA, as well as the space complex planned by ROSKOSMOS, including an orbital constellation of 6 small spacecraft for radar surveillance.
Performance of a second generation
X
-band rf photoinjector
