520 
3 X-band error rates of less than or equal to 
1 x 10-8 have been achieved in both direct access 
and via TDRSS, 
e Solar Array power output has been measured at 1200 
Watts. This exceeds the requirement for full 
spacecraft operation by 200%. 
$ MSS and TM performance has been nominal. The MSS 
coherent noise was reduced by 30% as a result of 
adding filters. 
THE LANDSAT-4/5 GROUND SEGMENT 
The Landsat-4/5 Ground Segment refers to the facilities 
and systems which perform satellite scheduling and control, 
image processing and production control functions. Ground 
Segment systems are located in Building 28 at GSFC. The 
major components of the Ground Segment and their functions 
are outlined in Figure 10. These systems were designed for 
and are dedicated to the Landsat-4/5 system. While initial 
system design was based on experience with earlier Landsats, 
considerable design modifications, especially in image 
processing, were introduced during development as more was 
understood of the TM instrument performance. 
DATA PROCESSING FOR THE THEMATIC MAPPER: DESIGN 
CONSIDERATIONS 
Processing of data from the TM, when compared with 
processing MSS data, poses formidable challenges. The 
Landsat-4/5 MSS is a fourth generation instrument whose 
on-orbit performance has been well characterized and is well 
understood. The ground processing of MSS data is also well 
understood. The Landsat-4/5 MSS Image Processing System 
(MIPS) is the final evolution of MSS data processing. The 
MIPS design and configuration take advantage of advances in 
hardware and computer technology, and improved software 
management, development, and implementation techniques. 
Lessons learned regarding process control and data 
management, and from years of analysis of MSS instrument and 
Landsat spacecraft performance, resulted in improvements in 
data correction techniques and algorithms... The.result 1s an 
efficient, reliable MSS data processing system that 
consistently produces high quality products in a high 
throughput, quick turnaround environment. M MS5 continues to 
be the primary source of earth resources data for the 
majority of users in the land remote sensing disciplines. 
The TM instrument, however, because of its complexity and 
unique design, is designated an R&D instrument. However, the 
performance requirements for radiometric and geometric 
Correction placed upon the data processing system for TM are 
identical with those. placed on the MSS. system. It was clear 
from the beginning that achieving geometric performance 
accuracies commensurate with M5S, that is * .5 pixel geodetic 
and + .3 pixel temporal registration accuracy, would be the 
most formidable challenge because of the smaller TM IFOV (30