Electrical interferences observed in the Cassini CIRS spectrometer

The Composite Infrared Spectrometer (CIRS) carried onboard the Cassini spacecraft has now operated successfully for 17 years, following launch in 1997. Following insertion into Saturnian orbit in July 2004, the instrument has taken data nearly continuously, returning over 100 million interferograms (spectra) to date. Although of generally high quality, and resulting in more than 100 peer-reviewed scientific articles, the spectra are afflicted with several types of instrumental electrical (non-random) noise artifacts. These noise artifacts require either mitigation strategies (prevention), removal from the observed data, or else awareness of the affected spectral areas which must be excluded from scientific analysis. The sources and nature of these varied noise types were not readily identified until after launch. The purpose of this article is to inform users of the noise in the CIRS dataset and to serve as a ‘lesson-learned’ guide for designers of future instruments.