Development of Test Capsule Falling through the Drop Shaft

The world's deepest drop shaft facility for microgravity experiments, using a former coal mine shaft of 710 m in depth was constructed at Kamisunagawa, Hokkaido, Japan in 1991. The rocket shaped capsule (1.8 m in diameter, 8 m in length and 5.7 ton in maximum weight), is falling through the drop shaft and produces microgravity of approximately 1 x 10 −5 g for 10 s. Microgravity is produced by floating the inner capsule, in which experimental devices are loaded, in the vacuum Pace of the outer capsule while falling. The outer capsule fall is controlled by a magnetic guidance system. Deceleration at braking is about 8g, which is performed by adopting an air braking method. A real time data transmission device between the falling capsule and the control room, including colour image, is installed.