As part of the upcoming AMADEE-27 Mars analog mission in Portugal, our team is hard at work on the “Caillou” project. Our goal is to develop a functional prototype of a Synthetic Raman Spectrometer, a payload designed to be integrated onto a robotic exploration platform to simulate the geological search for life on Mars.

Raman spectroscopy is a powerful, non-destructive tool used to identify minerals and potential biomarkers by observing how light scatters when it hits molecules. However, testing the operational workflows for such an instrument in the field can be difficult without expensive hardware. Our project aims to bridge the gap between computational simulations and real-world data acquisition. Instead of performing a real chemical analysis, our prototype acquires target information and provides physically plausible synthetic spectra from a pre-defined library to help mission operators practice scientific decision-making.

The design process began with a functional analysis to ensure the prototype mimics the behavior of a space-grade instrument while remaining a versatile guest-payload for various rovers. We identified two primary functions (FPs) that drive our design:

• FP1: Simulate Sample Analysis: The system must interact with a geological target to output a synthetic Raman curve. This requires a laser subsystem to visually simulate the Raman path and an acquisition subsystem to identify the target.
• FP2: Bi-directional telemetry: The instrument must be capable of receiving remote commands and transmitting camera images and spectral results back to the science backroom.

Our design philosophy has evolved significantly. Initially, we focused on a structure specifically for one rover. However, after discussing with another experiment team, we shifted towards a compact, transportable instrument. This new direction means the prototype can be operated in a lab, mounted on a variety of rovers and legged platforms, or even be manually carried by an analog astronaut in the field.
To make this a reality, we have to respect strict engineering constraints:

• Mass and volume: The latest budget estimates the instrument’s mass at approximately 500g, without the dedicated battery.
• Power: We are aiming for a peak power consumption of 20W.
• Environment: The prototype must feature protective seals to resist the shocks, vibrations, and dust typical of the analog mission site.
• Light suppression: To mimic a real spectrometer, we must ensure the sample is in a “dark chamber” during analysis to avoid interference from sunlight.
  

This design phase taught us that requirements aren’t just lines on a document, as they dictate every choice we make. Seeing our design process evolve from a fixed payload to a compact, transportable instrument has highlighted the balance required between scientific goals and hardware constraints.

Author: Cassandra Benichou-Dumont