The neutron Bonner Ball spectrometer, which measures the relatively low-energy neutron spectrum from thermal neutrons to 15 MeV, was installed on Space Shuttle Endeavour in 1998. In 2001, it was Japan's first installed instruments on space station. Mitsubishi Heavy Industries, Ltd. (MHI) is now developing a single-sphere-type spectrometer, which will be smaller than the conventional multi-sphere device. In the future, MHI aims to widen its application range to the aeronautical and nuclear fields.