Overview and Significance of Advanced Land Observing Satellites (ALOS)

Abstract

This paper provides an overview and discusses the significance of Advanced Land Observing Satellites (ALOS). Japanese Earth observation programs originally consisted of two branches: the Marine Observing Satellite (MOS) for global observation and the Land Observing Satellite (LOS) for more detailed observation. The first LOS mission was conducted by the Japanese Earth Resources Satellite-1 (JERS-1) from 1992 to 1996. It was followed by the Advanced Land Observing Satellite (ALOS, “Daichi”) from 2006 to 2011. Both achieved global data acquisition with high resolution using L-band Synthetic Aperture Radar (SAR) and optical instruments. ALOS-2, a successor of the SAR mission on ALOS, has been operating very well since 2014, and ALOS-3 and ALOS-4 are now being developed for launch in Japanese fiscal years (JFYs) 2021 and 2022 to follow the optical mission and ALOS-2, respectively. In this paper, I examine the history and future of the ALOS series.