| Name: Twinkle Sharma |
| Affiliation: Thapar Institute of Engineering and Technology |
| Conference ID: ASI2026_566 |
| Title: Design and testing of the payload for microsatellite- ThaparSat |
| Abstract Type: Oral |
| Abstract Category: Facilities, Technologies and Data science |
| Author(s) and Co-Author(s) with Affiliation: Twinkle Sharma(Thapar Institute of Engineering and Technology, Patiala - 147004, India), Mamta Gulati(Thapar Institute of Engineering and Technology, Patiala - 147004, India), Vineet Srivastava(Thapar Institute of EngThapar Institute of Engineering and Technology, Patiala - ineering and Technology, Patiala, 147004, India), Ravinder Kumar Duvedi(Thapar Institute of Engineering and Technology, Patiala - 147004, India) |
| Abstract: Accurate space-based monitoring of atmospheric greenhouse gases requires a well-designed payload and a precisely calibrated detector system. This study presents the design, development, and laboratory-based calibration of the optical payload developed for ThaparSat, a pollution-monitoring microsatellite intended for the retrieval of tropospheric concentrations of CO2, CH4, N2O, and H2O. The payload architecture involves the selection of an appropriate infrared spectral region, detector technology, and gas-specific narrowband filters to minimise spectral cross-interference and prevent absorption saturation effects. The instrument utilises a Mercury Cadmium Telluride (HgCdTe) focal plane array detector operating over the 2–5 µm spectral range, enabling the detection of strong and spectrally isolated absorption features of the target gases. Eight dedicated bandpass filters are integrated into the optical assembly to facilitate simultaneous multi-gas sensing. A radiative transfer model incorporating HITRAN absorption cross-sections and Lorentzian line-shape functions was developed to quantify the photon flux incident on each spectral channel under varying atmospheric conditions. For detector calibration and performance assessment, a laboratory-scale multi-pass gas absorption chamber employing a nine-mirror configuration was designed, providing an effective optical path length of 344 cm while preserving beam stability and optical throughput. The detector output, acquired as 16-bit grayscale digital data, was converted to electron counts and subsequently to photon flux using the system conversion gain. The radiative transfer model has been used for the experimental validation and close agreement between experimentally measured and theoretically estimated photon flux values validates both the and the overall payload design. |
