This invited keynote talk presents development of a tunable MEMS shutter array integrated with large-core rectangular multimode waveguides. This assembly can be used as an imaging spectrometer subsystem. It fulfills the function of the classical entrance slit of a grating spectrometer for spatial optical signal selection, combined with the possibility to homogenize the optical signal intensity and select subsets of the observable scene on demand. This solution is intended for use in space for observation of the earth and other planets and for atmospheric sciences, as well as for astronomy applications for multiobject spectroscopy.