Expectations for SAR (Synthetic Aperture Radar) satellites that can observe a target area through clouds and during nighttime are emerging, especially in Asia where high cloud cover rates prevent from the satellite monitoring with optical sensors. We will build a constellation of the small SAR satellites to realize short term revisits, shorter than one day to take advantage of SAR sensors that can acquire data regardless of weather and time in a day. We expect the constellation expands needs of the SAR data to business and private decision making, and develop a market for commercial use. We will launch the first demo satellite in 2020. We are already preparing to build the second satellite and will make six satellite constellation until 2022. Our final goal is to build a constellation of 25 satellites.