ANITA2 – the Advanced Multicomponent Air Analyser for ISS – Gas Measurement Results From the ISS Air in 2022

The ANITA2 (Analysing Interferometer for Ambient Air) instrument is a trace gas analyser designed to operate onboard the ISS to monitor the cabin atmosphere. ANITA2 can detect more than 40 of the most important trace gases in parallel. The advantages of an ANITA-type instrument include high sensitivity, accuracy, precision, and time resolution of the measurement data, as well as no consumption except electrical power and no production of waste. This also makes ANITA a steppingstone into the future, as a precursor system for crewed stations, bases, and exploration missions, including the Lunar Gateway and to/on the Moon and Mars. After a successful operation of ANITA1 for 11 months onboard the ISS in 2007 and 2008, the ANITA2 instrument was built in a contract between ESA, OHB and SINTEF and launched to the ISS in December 2021. ANITA2 started its regular operation on March 9, 2022, and it is at the time of writing monitoring 44 gas compounds in the ISS air. This paper covers ANITA2's gas analysis through the commissioning phase on the ISS and the following in-flight air analyses. After start-up, several off-nominal conditions were detected and handled through an updated calibration, which was uploaded to ANITA2 on the ISS for autonomous air monitoring. The updated calibration could also be applied offline to all previously measured spectra, to produce high-quality gas data from the entire period of operation. In addition to the updated calibration for use on the ISS, a semi-local ISS gas scenario was defined, to cover the observed gas variations plus smaller margins than the general scenario of the very robust main calibration. This calibration, which has further improved precision and detection limits for the gases present, was applied offline as basis for air analysis reporting to ESA and NASA.