The NASA ESTO funded Multislit Optimized Spectrometer (MOS) Instrument Incubator Program advances a spatial multiplexing spectrometer for coastal ocean remote sensing from laboratory demonstration to flight-like environment testing. The multiple slit design reduces the required telescope aperture leading to mass and volume reductions over conventional spectrometers when applied to the GEO-CAPE oceans mission. This paper discusses the performance and characterization of the MOS instrument from laboratory and thermal vacuum testing. It also presents the current technology readiness level and possible future applications. Results of an ocean color data product simulation study using flight-like performance data from MOS are also covered. The MOS instrument implementation for GEO-CAPE provides system benefits that may lead to measurable cost savings and reductions in risks while meeting its science objectives.