THE LANDSAT-5 SYSTEM: DESCRIPTION AND 
PRELIMINARY ASSESSEMENT 
William Webb 
William M. Watt 
NASA/Goddard Space Flight Center 
Greenbelt, Maryland 
United States of America 
Commisssion ILI 
INTRODUCTION 
Five satellites have served the Landsat program as 
earth-focused observatories, providing a continuous source of 
earth resources data since July 1972. Throughout. these 
twelve years, spacecraft, instrument and data processing 
technologies have evolved; and the resulting new developments 
have been incorporated into the Landsat Program. Major 
advances were introduced in all three areas with Landsat-4. 
The spacecraft is of the modular component design developed 
to be compatible with the U.S. Space Transportation System. 
It carries the advanced imaging Thematic Mapper (TM) 
instrument, and ground-based control and data processing is 
performed via systems designed for and dedicated to Landsat 
objectives. In addressing the present Landsat Program, we 
will refer to it as the Landsat-4/5 System. We will describe 
the major attributes of the Landsat-4/5 System which 
incorporates many design features driven by experience with 
the now-retired Landsats-] through 3, and we will examine 
system improvements introduced in the Landsat-5 era resulting 
from lessons learned in Landsat-4 operations. 
LANDSAT HISTORY 
Landsats-1, 2 and 3 were launched in 1972,: 1975 and 
1978, respectively. All of these spacecraft functioned 
successfully well beyond their design lifetimes of one year. 
Landsat-1 operations terminated in 1978 and Landsat-2 and 3 
operations terminated in 1983. Over 1,200,000 Multispectral 
Scanner (MSS) scenes and 270,000 Return Beam Videcon (RBV) 
scenes were acquired by the United States and over 90 percent 
archived for analyses and application. Approximately 2.5 
times the number of scenes acquired by the United States were 
acquired by the several ground receiving and processing 
stations operated by other countries. This sizable 
collection of data from the Landsat 1-3 series thus made a 
very significant impact in providing inventories and improved 
understanding of the characteristics of the land cover of the 
earth and associated resources. Evidences of the use of 
Landsat data products appear in numerous scientific and 
technical journal articles, magazines, handbooks and 
textbooks.