Estimation of Earth Reflection Spectral Radiation Flux and External Stray Radiation From a Moon-Based Spectral Radiometer

Abstract

A Moon-based spectral radiometer (MBSR) can continuously measure the Earth’s outward total reflection spectral radiative flux across different phases, offering valuable insights into climate studies, the search for extraterrestrial life, and the quest for habitable planets. Establishing the spectral radiation measurement model and analyzing stray radiation of MBSR are crucial for parameterizing the instrument. By utilizing a Sun-Earth-Moon geometric model, the Earth’s reflection spectral irradiance and stray radiation spectral irradiance models at the instrument’s pupil are established, enabling the evaluation of spectral radiation under various observation phases. The measurement conditions of MBSR are analyzed, and the key parameters of the instrument’s input dynamic range and external stray radiation suppression requirements are proposed. The results show that the spectral irradiance range of the Earth reflection spectrum at the entrance pupil of the instrument in the measurement band of 300-2500 nm is 0- $2.5^{\ast } 10^{-4}$ W/m2 /nm, and the external stray light inhibition ratio should be less than $10^{-9}$ . The development of a Moon-based Earth observation model and the analysis of external stray radiation play a pivotal role in supporting the design and advancement of the MBSR.

Keywords

• Analysis
• entrance pupil spectral irradiance
• earth observation
• spectral radiation
• stray radiation