10:45 AM - 12:15 PM
[PCG18-P16] Ground-based calibration and peformance test of TIRI on Hera mission
ESA’s Hera mission will explore a binary S-type asteroid Didymos. JAXA develops a thermal infrared multi-band imager TIRI. Scientific goal of TIRI is to reveal the thermophysical properties and infrared spectral properties of the S-type asteroid, as well as an artificial crater on its moon Dimorphos formed by the spacecraft impact via DART mission. TIRI consists of an uncooled micro-bolometer array of 1024 x 768 pixels, optics with the field of view of 13.3 x 10.0 degrees, 7 filters including wide bandpass covering 8-14 μm wavelength and 6 narrow bands at 7.8, 8.6, 9.6 10.6, 11.6, and 13.0 μm.
We performed ground-based calibration tests of the engineering model (EM) of TIRI on February 2023. We will present the result of the calibration and multi-band performance test using rocks and meteorites.
TIRI is placed on a 2-axis gimbal, which enables us to change the attitude of TIRI inside the vacuum chamber. Heat generation during the operation is designed to be escaped to the cooling plate from the radiator through flat copper braid cables. In front of the TIRI FoV, an IR-transparent Ge window is installed, through which IR targets outside the vacuum chamber can be imaged.
We prepared three IR calibration targets. First is the IR collimator with target viewing angle of 0.1 to 2.8 degree and target temperature range from -20 to +150 degC. Second is a blackbody furnace. The area is 178mm x 178mm, and temperature range is 20 to 125 degC. The last one is the low tempareture blackbody plate with temperature range of -120 to +20 degC. Only the low-temperature blackbody plate is installed in the vacuum chamber, and others are observed through the Ge window. Using these targets with different temperatures, sizes, and viewing angles, we will show the result of radiometric calibration, size-of-soruce effect correction, instrument temperature correction, and distortion correction. Furthermore, we will have a plan to carry out the multi-band imaging of collimated radiation from some reference minerals such as rocks, and meteorites. This will allow us to evaluate the performance of TIRI EM.
We performed ground-based calibration tests of the engineering model (EM) of TIRI on February 2023. We will present the result of the calibration and multi-band performance test using rocks and meteorites.
TIRI is placed on a 2-axis gimbal, which enables us to change the attitude of TIRI inside the vacuum chamber. Heat generation during the operation is designed to be escaped to the cooling plate from the radiator through flat copper braid cables. In front of the TIRI FoV, an IR-transparent Ge window is installed, through which IR targets outside the vacuum chamber can be imaged.
We prepared three IR calibration targets. First is the IR collimator with target viewing angle of 0.1 to 2.8 degree and target temperature range from -20 to +150 degC. Second is a blackbody furnace. The area is 178mm x 178mm, and temperature range is 20 to 125 degC. The last one is the low tempareture blackbody plate with temperature range of -120 to +20 degC. Only the low-temperature blackbody plate is installed in the vacuum chamber, and others are observed through the Ge window. Using these targets with different temperatures, sizes, and viewing angles, we will show the result of radiometric calibration, size-of-soruce effect correction, instrument temperature correction, and distortion correction. Furthermore, we will have a plan to carry out the multi-band imaging of collimated radiation from some reference minerals such as rocks, and meteorites. This will allow us to evaluate the performance of TIRI EM.