  The X-ray Integral Field Unit (X-IFU) is the high-resolution X-ray
spectrometer to fly on board the Athena Space Observatory of the European Space
Agency (ESA). It is being developed by an international Consortium led by
France, involving twelve ESA member states, plus the United States. It is a
cryogenic instrument, involving state of the art technology, such as
micro-calorimeters, to be read out by low noise electronics. As the instrument
was undergoing its system requirement review (in 2022), a life cycle assessment
(LCA) was performed to estimate the environmental impacts associated with the
development of the sub-systems that were under the responsibility of the X-IFU
Consortium. The assessment included the supply, manufacturing and testing of
sub systems, as well as involved logistics and manpower. We find that the most
significant environmental impacts arise from testing activities, which is
related to energy consumption in clean rooms, office work, which is related to
energy consumption in office buildings, and instrument manufacturing, which is
related to the use of mineral and metal resources. Furthermore, business
travels is another area of concern, despite the policy to reduced flying
adopted by the Consortium. As the instrument is now being redesigned to fit
within the new boundaries set by ESA, the LCA will be updated, with a focus on
the hot spots identified in the first iteration. The new configuration,
consolidated in 2023, is significantly different from the previously studied
version and is marked by an increase of the perimeter of responsibility for the
Consortium. This will need to be folded in the updated LCA, keeping the
ambition to reduce the environmental footprint of X-IFU, while complying with
its stringent requirements in terms of performance and risk management.
