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information extraction, the success of this type scanner, therefore, was 
less than anticipated. 
The addition of the 240m resolution thermal channel and the 40m panchro- 
matic videcons to Landsat-3 is expected to improve stress detection and 
edge definition capabilities. The 30m resolution Thematic Mapper of 
Landsat-D is expected to improve vegetation classification. In addition, 
the seven optimized bands should enhance the agriculture and land use 
applications as well as assisting geologists in their search for mineral 
deposits and energy sources. 
A Large Format Camera will provide stereo photography in both black and 
white and color infrared that is of primary interest to geologists. 
Each of these sensors is discussed in the following material. 
Multispectral Scanner (MSS) - An MSS of the Landsat-3.design will be 
flown on Landsat-D, together with the Thematic Mapper scanner. The 
basic MSS scans across-track with a resolution element of about 79 meters. 
The spectral bands of the basic MSS are 0.4 to 0.5, 0.5 to 0.6, 0.6 to 
0.7, and 0.8 to 1.1 microns. The thermal infrared channel, added on 
Landsat-3, has a resolution element of 240 meters and a spectral range of 
from 10.4 to 12.6 microns. Multispectral scanners have proven to be 
very useful and durable instruments. 
Thematic Mapper (TM) - NASA has received approval to develop the 
first USA space optical scanning system that has band widths selected 
primarily for vegetation analysis. This scanner is to be first launched 
on Landsat-D during 1981. The Landsat-D system is planned to provide 
earlier availability of data to the user than previous systems, as well as 
frequent coverage, and precise data registration and overlay for better 
change detection. 
The bands for the TM have been chosen primarily on the basis of their 
ability to discriminate vegetation, since this capability is fundamental 
to many important applications of remote sensing. Furthermore, they 
have been selected to avoid, as much as possible, the absorption bands 
of atmospheric water vapor. Since this factor is an important element 
in limiting the requirements for signature extension (both temporally 
and spatially), avoiding the effects of atmopsheric water vapor results 
in a significant improvement in Earth resources remote sensing capability. 
The bands selected and their particular value to various applications 
follow. 
0.45 - 0.52 um Water depth measurements; soil/vegetation 
differences; deciduous/coniferous differentia- 
tion; land use mapping. 
0.52 - 0.60 um Vegetation density; growth stage determination; 
vegetation vigor (disease detection); suspended 
sediments in water bodies; waste disposal plume 
detection in water.