On-orbit Calibration and Performance of the EMIT Imaging Spectrometer
AbstractThe Earth surface Mineral dust source InvesTigation (EMIT) is a remote visible to shortwave infrared (VSWIR) imaging spectrometer that will map the mineralogy of Earth's mineral dust forming regions. EMIT was launched to the International Space Station in July 2022, beginning a year-long mission. This article describes the EMIT spectroradiometric calibration and on-orbit validation experiments. EMIT achieves several notable firsts for an instrument of its class. It demonstrates successful on-orbit adjustments of Focal Plane Array (FPA) alignment with sub-micron precision. It offers spectral uniformity better than 98%. Optical artifacts in the measurement channels are at least three orders of magnitude below the primary signal. EMIT consists of just six optical elements, no shutter, and no onboard calibration systems. With this simple and efficient design, EMIT satisfies the stringent needs for the next generation of VSWIR imaging spectrometers.