TRMM (Tropical Rainfall Measuring Mission) is the first space mission dedicated to quantitatively measuring tropical and subtropical rainfall which is one of the most important and least-known parameters affecting the global climate system. ETS-VII (Engineering Test Satellite, “Kiku 7”) was launched aboard the H-2 No. 6 rocket from Tanegashima Space Center in November 1997.mETS-VII itself comprises two satellites: “Orihime” and “Hikoboshi”. “Orihime” is a target satellite weighing approximately 400 kilograms. It is placed in a fixed circular orbit at an altitude of roughly 550 kilometers. “Hikoboshi” is a chaser satellite, weighing some 2.5 tons. It moves in a variable orbit to rendezvous and dock with “Orihime”. “Hikoboshi” is equipped with a six-jointed, three-clawed robot arm two meters long.