Detection of composition, space weathering, and local resurfacing using ASPECT hyperspectral imager of ESA Hera / Milani mission

ASPECT is a flexible hyperspectral imager based on tunable Fabry-Perót interference filter (Näsilä and Kohout 2020). It consists of three independent Vis-NIR imaging channels, one single-point SWIR spectrometer, and a dedicated data processing unit (DPU) based on Xiphos Q7 (Table 1). ASPECT is the prime payload of Milani CubeSat carried by ESA Hera mission (Michel et al. 2022, Kohout et al. 2018) to binary asteroid Didymos-Dimorphos and is also considered for missions to asteroid Apophis.

Tests of ASPECT performance to resolve spectral features of chondritic materials spectra were done with Bjurböle L/LL4 meteorite. 1-µm silicate band is well resolved (Fig. 1) and SNR around 100 in Vis channel and 40 in NIRs channels can be achieved.

ASPECT will conduct global hyperspectral mapping of the target asteroids with a resolution of 1 m/px from 5 km. The spectral domain contains key information on surface composition and maturity. Combined with high spatial resolution lateral variations in surface properties can be mapped.

Table 1.

Fig. 1. Comparison of Bjurböle meteorite measurements with ASPECT (green, red) against the reference laboratory spectrometer (blue). The 1-µm silicate band is well resolved.

References:

Michel et al. 2022 DOI 10.3847/PSJ/ac6f52

Näsilä, Kohout 2020 DOI 10.1109/AERO47225.2020.9172437

Kohout et al. 2018 DOI 10.1016/j.asr.2017.07.036