Editing Mariner 9 (section)

=== Infrared Interferometer Spectrometer (IRIS) ===
The Infrared [[Interferometry|Interferometer]] Spectrometer (IRIS) measured [[thermal radiation]] emitted by Mars to analyze atmospheric composition, surface temperature, and dust properties. It worked on a wavelength range of 6–50 μm with a spectral resolution of 2.4 cm<sup>-1</sup>.<ref>{{Cite web |title=Mariner 9 Infrared Interferometer Spectrometer - NASA Planetary Data System |url=https://arcnav.psi.edu/urn:nasa:pds:context:instrument:iris.mr9  |access-date=2025-02-27 |website=arcnav.psi.edu}}</ref>

The instrument confirmed the presence of [[Carbon dioxide|CO<sub>2</sub>]] as the dominant atmospheric gas; detected water vapor in the Martian atmosphere; measured surface and atmospheric temperatures and provided insights into dust storms' thermal properties.