Operational challenges for astronomical instrumentation in Antarctica: results from five years of environmental monitoring of AMICA at Dome C

The Antarctic Plateau is one of the best observing sites on Earth, especially for infrared astronomy. The extremely low temperatures (down to -80°C), the low pressure (around 650 mbar) and the very dry atmosphere (PWV less than 1 mm) allow for a very clear and dark sky, as well as for a very low instrumental background. These unique properties, however, make it also very difficult to install and operate astronomical instrumentation. AMICA (Antarctic Multiband Infrared CAmera) is an instrument especially designed for Antarctic operation, whose installation at Dome C has been completed in 2013. Since then it has been continuously working over the last five years, monitoring and controlling in particular the environmental and operating conditions through a dedicated application, its Environmental Control System (ECS). The recorded behavior of AMICA highlighted a set of peculiar aspects of the site that are hard to consider a priori. Although mechanical and electronic COTS components can reliably work in thermally insulated and controlled boxes, simple insulation causes their overheating because of the air dryness and rarefaction which make the heat transfer extremely inefficient. Heat removal is also a real problem when managing heavy-duty devices like cryocoolers, whose excess power removal needs to be fast and efficient. Finally, the lack of an electrical ground generates a wide variety of transient electrical and electromagnetic phenomena which often make electronic instrumentation very unstable. A list of new recommendations is therefore presented, as a guideline for future astronomical instruments operating in Antarctica.