This article describes the ongoing work of our interns on the Caillou project – a synthetic Raman spectrometer for AMADEE-27.  To learn more about idea and design process read this article: https://oewf.org/en/2026/06/synthetic-raman-spectrometer-for-amadee-27/. The second article describes the process how to develop a prototype: https://oewf.org/en/2026/07/from-concept-to-prototype-bringing-the-caillou-instrument-to-life/

In this third article our intern Maxime Poulain describes how to build the actual prototype with hardware.

Before diving into the nuts and bolts of building a space instrument, it helps to know what we set out to create. The CaillouInstrument is a compact, lightweight scientific instrument designed for planetary exploration—specifically tailored to operate in harsh, Mars-like environments. Built to support analog space missions like AMADEE–27, Caillou integrates an optical imaging subsystem, precise laser guidance, and onboard processing into a custom modular enclosure, all while sticking to a strict mass budget of around 500 grams.

This article details the Assembly, Integration, and Verification (AIV) phase of the project. It tracks our journey as we moved from initial 3D computer-aided design (CAD) models to a fully functional, field-ready physical prototype capable of withstanding dust, shock, and severe environmental constraints.

The Integration Challenge: Moving from Virtual to Concrete

Transitioning from computer-aided design (CAD) to actual 3D-printed parts was a significant milestone for our team. The primary goal of this phase was to integrate all our commercially available components into our custom-designed enclosure while respecting our tight mass budget of approximately 500g (excluding the dedicated battery).

Hands-on integration centered around several key elements:

• The Brain of the System: Installing the Raspberry Pi. Adjusting mechanical tolerances so the board fit securely within the custom enclosure required meticulous attention to ensure structural robustness during transport.
• The Optical Subsystem: Precisely aligning the camera module and the visible laser guide. These components must line up perfectly to handle target acquisition and capture the context images needed by the science team.
• Power Management: Wiring the system to a lightweight power bank sized to sustain our targeted peak power consumption of 20W.

Verification Phase: Facing the Martian Constraints

• A scientific instrument is only valuable if it can be operated efficiently in the field. To validate our prototype under conditions representative of AMADEE-27 , we initiated rigorous testing based on our environmental engineering constraints:
• Light Suppression: To accurately mimic a real spectrometer, we verified that the sample sits completely inside a “dark chamber” during the simulated analysis to prevent any interference from sunlight.
• Environmental Resilience: Testing the protective seals of our modular enclosure to ensure the onboard electronics remain shielded from the shocks, vibrations, and dust typical of the analog mission site.

What This Experience Taught Me

Working on the AIV phase at the Austrian Space Forum (OeWF) taught me that hardware engineering is a continuous balancing act between scientific goals and real-world hardware constraints. Seeing the final modular enclosure come together is incredibly rewarding.

Author: Maxime Poulain