14:45 〜 15:00
[PPS03-17] ASPECT hyperspectral imager for ESA Hera mission - Verification of instrument performance in laboratory and definition of science operations
キーワード：Hyperspectral imaging, Asteroid composition, Reflectance spectrum, CubeSat instrumentation
The Asteroid Spectral Imager (ASPECT) is a hyperspectral imager carried by the Milani CubeSat, one of the two nanosatellites onboard the Hera spacecraft. Hera is part of a collaborative mission between the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) and was launched into space in October 2024 to study the binary asteroid system Didymos-Dimorphos.
ASPECT is used to investigate the spectral signature of Dimorphos, determining its geomorphology, optical properties, space weathering, and composition. Additionally, ASPECT will examine the shock effects caused by the Double Asteroid Redirection Test (DART). ASPECT operates across three channels within the visible, near-infrared, and short-wave infrared spectrum, with the latter being a non-imaging channel.
In order to collect accurate key diagnostic mineralogical information with minimal data volume, ASPECT needs to be tested to identify optimal spectral step and exposure times. ASPECT covers the 1 µm band, which is contributed by both olivine and pyroxenes. These particular silicates are distinctive of S-type asteroids, such as the Didymos-Dimorphos binary asteroid system. By analysing the shape of spectral band, it is possible to resolve the abundances of these minerals.
The tests were conducted by measuring the reflectance spectra of the meteorite samples Bjurböle and Saratov with ASPECT. These meteorites possess mineralogical properties similar to those of the Didymos-Dimorphos system. The samples were imaged using the ASPECT Flight Spare with varying spectral sampling step, exposure times, and illumination intensity. The reflectance spectra obtained with ASPECT were compared to the high-quality Bjurböle and Saratov spectra measured with a laboratory spectrometer.
The study suggests that the spectra obtained with ASPECT under various conditions exhibit absorption properties identical to those observed in the laboratory-derived spectra of Bjurböle and Saratov. The silicate absorption bands at the 1 µm are identified from the ASPECT measured spectra. However, relative noise increases as function of decreasing exposure time and irradiation in the visible and near-infrared channels.
The results indicate that ASPECT is able to identify the key mineral absorption properties. The longest exposure time and highest irradiance settings used in this study lead to the acquisition of images of the highest quality. Additionally, further investigation is required to optimize the operation of the visible channel.
ASPECT is used to investigate the spectral signature of Dimorphos, determining its geomorphology, optical properties, space weathering, and composition. Additionally, ASPECT will examine the shock effects caused by the Double Asteroid Redirection Test (DART). ASPECT operates across three channels within the visible, near-infrared, and short-wave infrared spectrum, with the latter being a non-imaging channel.
In order to collect accurate key diagnostic mineralogical information with minimal data volume, ASPECT needs to be tested to identify optimal spectral step and exposure times. ASPECT covers the 1 µm band, which is contributed by both olivine and pyroxenes. These particular silicates are distinctive of S-type asteroids, such as the Didymos-Dimorphos binary asteroid system. By analysing the shape of spectral band, it is possible to resolve the abundances of these minerals.
The tests were conducted by measuring the reflectance spectra of the meteorite samples Bjurböle and Saratov with ASPECT. These meteorites possess mineralogical properties similar to those of the Didymos-Dimorphos system. The samples were imaged using the ASPECT Flight Spare with varying spectral sampling step, exposure times, and illumination intensity. The reflectance spectra obtained with ASPECT were compared to the high-quality Bjurböle and Saratov spectra measured with a laboratory spectrometer.
The study suggests that the spectra obtained with ASPECT under various conditions exhibit absorption properties identical to those observed in the laboratory-derived spectra of Bjurböle and Saratov. The silicate absorption bands at the 1 µm are identified from the ASPECT measured spectra. However, relative noise increases as function of decreasing exposure time and irradiation in the visible and near-infrared channels.
The results indicate that ASPECT is able to identify the key mineral absorption properties. The longest exposure time and highest irradiance settings used in this study lead to the acquisition of images of the highest quality. Additionally, further investigation is required to optimize the operation of the visible channel.