Japan: On the occasion of 25th anniversary of the Experimental Geodetic Satellite “AJISAI” (EGS), International Laser Ranging Service (ILRS) sent a letter of appreciation to its team.
The letter mentioned, “The launch of AJISAI came at a time when we had few dedicated geodetic satellites and demand for precise SLR tracking data was increasing each year due to the major efforts underway to improve the gravitational model for earth. The data from AJISAI was a major contributor to gravity field models of the time and continues to play an important role not only in gravity field modelling but also for instrument performance assessment and calibration. The satellite legacy will continue through its long term contribution to studies of the secular and periodic variations of earth’s low degree zonal harmonics. Along with LAGEOS and STARLETTE, AJISAI’s long historical impact will be felt in record of gravitational variations that continues to be vital in the study of climate change.”
AJISAI was launched on August 13, 1986, to confirm and establish Japan’s geodetic datum. It has been observing the Earth for such a long time to contribute to various fields including mapping nautical charts (Japan Coast Guard), communication and positioning experiments and technological development (National Institute of Information and Communications Technology), research on rotation of satellites (Geospatial Information and Authority of Japan), and acquisition of precision orbit determination technology by laser ranging (JAXA), as well as the determination of about the 36th to 50th gravity field model.
Above all, AJISAI’s observations were very helpful for the long-term analysis of the Earth’s movement. Hence, it has been highly evaluated by the ILRS, which supports the world’s geodetic science, for its scientific and international significance and its technological ability through its long-term observations and research.