LOUPE: Observing Earth from the Moon to prepare for detecting life on Earth-like exoplanets

TL;DR

LOUPE is a lunar spectro-polarimeter designed to observe Earth as an exoplanet, providing critical data to improve detection and characterization of Earth-like exoplanets and their potential biosignatures.

Contribution

This paper introduces LOUPE, a novel lunar observatory instrument that captures spectral and polarimetric data of Earth to aid exoplanet research and future mission planning.

Findings

Provides continuous spectral and polarimetric data of Earth from the Moon

Tests numerical models predicting signals of Earth-like exoplanets

Informs design and observational strategies for future space telescopes

Abstract

LOUPE, the Lunar Observatory for Unresolved Polarimetry of the Earth, is a small, robust spectro-polarimeter with a mission to observe the Earth as an exoplanet. Detecting Earth-like planets in stellar habitable zones is one of the key challenges of modern exoplanetary science. Characterising such planets and searching for traces of life requires the direct detection of their signals. LOUPE provides unique spectral flux and polarisation data of sunlight reflected by the Earth, the only planet known to harbor life. This data will be used to test numerical codes to predict signals of Earth-like exoplanets, to test algorithms that retrieve planet properties, and to fine-tune the design and observational strategies of future space observatories. From the Moon, LOUPE will continuously see the entire Earth, enabling it to monitor the signal changes due to the planet's daily rotation, weather patterns, and seasons, across all phase angles. Here, we present both the science case and the technology behind LOUPE's instrumental and mission design.