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Study of the response of ultra-sensitive spectrometers in tenuous planetary atmospheres


Most studies of the atmospheres of the planets in the solar system are carried out remotely, using telescopes equipped with spectrometers (remote sensing). Although this method yields numerous results, it does not offer the sensitivity or spatial resolution of on-site measurements using an optical spectrometer such as those developed in the laboratory for very high-precision spectroscopy. Directly measuring the abundance of gases and their isotopologues in the Martian atmosphere, for example, would enable us to better understand the dynamics of its atmosphere and therefore, ultimately, the activity of its subsoil, the source of much speculation.

If developing an instrument that can be deployed on a planet other than Earth is a challenge in itself, it is first and foremost necessary to ensure, in the laboratory, the validity of the measurements it will make under the conditions it will encounter.

The aim of this internship is to study and model the response of a cavity-ring-down-spectrometer (CRDS) measuring gases under Martian conditions, i.e. in an atmosphere of around 6 mBar CO2 and in the presence of trace gases, including very small quantities of water. One of the first questions is the linearity of measurement at low pressure, in the presence of saturation of molecular transitions. We propose to study the absorption lines of water in order to better define the characteristics and performance expected from a CRDS spectrometer that could be deployed on Mars.

This 6-month internship is aimed at a Master 2 student.


​LAME team (samir[dot]kassi[at]univ-grenoble-alpes[dot]fr)

LAME team (helene[dot]fleurbaey[at]univ-grenoble-alpes[dot]fr)

Submitted on February 13, 2024

Updated on February 13, 2024