Preparing for an Observation Mission

Launched in March 2025, UVSQ-SAT NG is a French 6U CubeSat carrying a compact, miniaturized near-infrared (NIR) spectrometer. This chapter describes the pre-flight calibration process for the UVSQ-SAT NG NIR (UNIS) spectrometer, focusing on the spectral response function, absolute calibration of the instrument and the mission objective of the UVSQ-SAT NG project. The absolute scale of the UNIS spectrometer was accurately calibrated using a quartz-halogen lamp with a twisted tungsten filament, certified by the National Institute of Standards and Technology (NIST) as a spectral irradiance standard. Ground measurements of direct SSI through NIR atmospheric windows taken with the UNIS spectrometer are also detailed. The chapter provides an overview of the methodology used to obtain the extraterrestrial spectral signal from UVSQ-SAT NG based on the Langley tracing technique. It presents an example of the implementation of an onboard device as a payload on a CubeSat.