An overview of the on-ground and in-orbit calibration of Far-Ultraviolet Spectrographs for the Aspera SmallSat

Aspera is a NASA Astrophysics Pioneers SmallSat mission consisting of twin Far-UV spectrographs designed to study diffuse OVI emission (λrest = 103.2 nm) from the warm-hot phase of coronal gas in the halos of nearby galaxies. The two identical spectrographs are optimized to operate in the 103-104 nm share a Cross-delay line (XLD) Microchannel Plate detector. The payload is currently being assembled at the University of Arizona, the payload is expected to integrate into the spacecraft by late 2024-early 2025. In this paper, we provide an overview of the ongoing ground calibration and performance verification activities of the instrument and the planned in-orbit calibration activities during mission operations. During these calibrations, we will measure the spectral, spatial resolution, photometric, and astrometric performance of the instrument. These measurements will be used to derive the wavelength solution, effective area, in-orbit noise, and pointing models. These results will be applied in the data pipeline for calibration of the science data.