Passive Thermal Mapping Without In-Zone Electronics: Optical Visualization of Temperature and Thermal History in Ground-Based and Extreme Environments

Temperature measurement in zones where communication and power supply are difficult—such as the permanently shadowed regions (PSRs) at the lunar south pole, radio-shielded areas on planetary bodies, and the interior of densely packed circuit boards—is problematic for conventional approaches that depend on electronic sensors together with their communication and power supply. This paper proposes a way to visualize temperature and thermal history in such zones without placing electronic components in them. Thermochromic materials are laid down to convert temperature into color, and the color is read remotely by an optical node at a boundary edge where sunlight and communication are available (or by the optical system of an orbiting satellite). The same principle can be applied on the ground, for example to wiring and circuit boards. Status: This is a conceptual proposal (preprint). It contains no experimental results and has not been peer reviewed. A plan for preliminary experiments is included (Chapter 7). The material requirements for cryogenic use are proposals; no suitable off-the-shelf material has been confirmed. Numerical estimates are idealized and rely on stated assumptions. Parts of the drafting and review were assisted by AI tools (Claude, Gemini, ChatGPT); the author is responsible for the content.