Knowledge Bank

The Mariner 9 spacecraft carried an infrared spectroscopy experiment to Mars in the latter part of 1971. The infrared emission spectrum of Mara was measured from 200 to 2000 $cm-1$ (50 to 5 $\mu$m) with an apodized resolution of $2.4cm-1$. Analysis of the spectra has yielded planetary surface and atmospheric temperatures and composition as well as other planetary parameters. Upper limits to minor atmospheric constituents have now been derived from the spectra. With an effective noise equivalent radiance of $1.2\times 10-9Wcm-2$ $ster-1/cm-1$ new upper limits of 4 $\times 10-4$ cm-atm for $NH3,6\times 10-4$ cm-atm for OCS, $1\times 10-2$ cm-atm for NO, and $6\times 10-4$ cm-atm for $CH4$ have been derived.