?Mariner 9 began a Mars orbit on November 14, 1971. An infraredEinterferometer spectrometer (IRIS) was one of five instruments in theEexperiment. IRIS has a range of 200-2000 inverse cm (50-5 um), and aFspectral resolution of 2.4 inverse cm. The data is distributed by theENational Space Science Data Center (NSSDC). For more information seeGthe Mariner 9 IRIS Documentation for Reduced Data Records (RDR), NSSDC, X-622-73-305.* Principle Investigator: R. A. Hanel,: Goddard Space Flight Center,' Code 690,3 Greenbelt, MD 20771.@A Mariner 9 IRIS data record has 100 ancillary items followed byM1500 spectral points for a record length of 1600 real * 4 words (6400 bytes).FAll items are referred to by their location or 'field' relative to theGbeginning of the record; thus, the first spectral point is field 101.