Development of the Lunar Earth Temperature Observatory (LETO) infrastructure for the Earth-Moon-Mars (EMM) project

The Earth-Moon-Mars (EMM) project was recently selected within the Italian National Recovery and Resilience Plan (PNRR). The project was proposed by the Italian National Institute of Astrophysics (INAF) in collaboration with the Italian Space Agency (ASI) and the Italian National Research Council (CNR). One of the goals of the project is the development of an infrastructure to be deployed on the lunar surface. With this infrastructure, CNR is involved in the development of an Earth observing system, named LETO (Lunar Earth Temperature Observatory) including a Fourier transform spectro-radiometer (LETO-FTS) and an imager (LETO-IMG). These two instruments, akin to the sensors embarked on the ESA Earth Explorer 9 FORUM mission [1], will continuously monitor the brightness temperature and the outgoing longwave radiation (OLR) flux of the whole Earth’s disk. Specifically, the LETO-FTS will measure the spectral radiance emitted by the whole Earth’s disk, in the far-IR (FIR) mid-IR (MIR) range, approximately between 100 and 1600 cm-1 (6-100 μm in wavelength), with a spectral resolution higher than 0.5 cm-1 and an unprecedented temporal resolution of a few minutes. The LETO-IMG images will permit to identify possible thermal anomalies related to severe events, such as large fires, volcanic eruptions, etc., that might have an impact on the Earth mean temperature measured by the FTS.