Active optics for a formation flying synthetic aperture telescope

In recent years, small satellites have been utilized for remote sensing from low earth orbit (LEO) with a spatial resolution of several meters. However, improving the temporal resolution for LEO remote sensing is challenging because of the short orbital period. Observation techniques using remote sensing from a geostationary orbit (GEO), or its nearby orbit are becoming increasingly crucial, particularly in disaster monitoring, due to their ability to provide high-temporal resolution. To improve both temporal and spatial resolutions from GEO, it is necessary to use an optical system with a diameter of several meters due to the diffraction limit. We propose the Formation Flying Synthetic Aperture Telescope (FFSAT). One of the key issues is realizing the optical system with an accuracy of less than 1/10 of the observation wavelength to get synthesized images. We propose a method for estimating and correcting misalignment and optical aberrations using adaptive optics.