Scientific objectives and specification of the SELENE Multiband Imager

The Lunar Imager/SpectroMeter (LISM) is an instrument being developed for onboarding the SELENE satellite that will be launched in 2007. The LISM consists of the three subsystems: Terrain Camera (TC), Multiband Imager (MI), and Spectral Profiler (SP).The MI is a high-resolution multiband imaging camera consisting of two visible and near infrared sensors. It takes push-broom imaging data by using selected lines of area arrays. The spectral band assignments are 415, 750, 900, 950 and 1000 nm for visible and 1000, 1050, 1250 and 1550 nm for near infrared. The spatial resolution of visible bands is 20 m, and that of near infrared bands is 62 m from the 100 km SELENE orbital altitude.We will observe globally the mineral distribution of the lunar surface in nine band images of MI. Its high spatial resolution will also enable us to investigate small but scientifically very important areas such as crater central peaks and crater walls. The advantage of MI for this aspect is that we can remove topographic effect, which causes false reflectance values seen in the crater wall and crater central peak, by photometric correction with detailed topography.Measurements of MTF, viewing vector, sensor linearity, and stray light and electrical noise level were carried out after the MI integration. Measured data indicate that MI will provide sufficient MTF, low noise and low stray light of spectral imaging data just as estimated in the MI designing phase.