sentences:  On May 18, 2012, the first satellite "GCOM-W1" (nickname "Shizuku") was launched.On December 23, 2017, the second satellite "GCOM-C1" (nickname "Shikisai) was launched.GCOM-W1 (Global Change Observation Mission – Water "Shizuku") is the first in the GCOM-W series.