The ANITA2 (Analysing Interferometer for Ambient Air) instrument is a trace gas analyser on board the ISS to monitor cabin atmosphere. ANITA2 has been built in a contract between ESA, OHB and SINTEF commissioned in Q1 of 2022. Since then, ANITA2 is monitoring the ISS gas environment providing detailed analysis for more than 40 gases in real time every 6 minutes. ANITA 2 is running 24/7 365 and proved a reliable instrument, delivering more than 120000 data points for each gas over its lifetime. Throughout ANITA2's operation all down times (significant interruptions of the measurement cycle) were due to OPS constrains and not imposed by ANITA2. This paper shows the two setups on board the space station in which ANITA2 has been operated in since commissioning, discusses possible life limiting items and their aging, and the hardware performance including opto-mechanical sensitivity, stability, and reliability. The concept for the next generation ANITA is presented and shown how lessons learned will be implemented. ANITA2 performance is limited not by optical stability of the instrument but by the fact that absorption spectra of gases are temperature dependent. Since, during cis-lunar missions, environmental temperature might vary significantly over time (crewed and uncrewed phases), a concept for gas cell temperature control is proposed and discussed in further detail.
Gisi et al. (2024) studied this question.