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and the way they would interact. TIPS was designed to be 
modular to facilitate the modification of major functions or 
Processes with minimal impact to others, as instrument and 
ground processing performance became better understood and 
practical limitations defined. 
A comprehensive engineering and interactive capabili- 
ty was included to facilitate development as well as data and 
process analysis. As system needs became clearer during TIPS 
implementation this capability was redefined and improved. 
Because of the extreme complexity of the TIPS 
special purpose hardware, numerous device diagnostics and 
built-in test capabilities were provided. With operational 
experience this capability has been improved and expanded to 
provide more meaningful process and device diagnostics. 
The importance of comprehensive reporting capability 
was recognized and provided for. As instrument and process 
performance have become better understood, the system 
reporting capability has also evolved so that now, detailed 
statistics on every key aspect of system performance can be 
routinely provided. 
A need to modify some aspects of the TM R&D activity 
was dictated by operational experience and actual instrument 
and ground processing performance. The R&D period also 
pointed out several deficiencies in the TIPS design. As an 
example, the current design does not allow the implementation 
of scan level radiometric corrections. 
Operational experience has identified deficiencies 
in process control and data management, particularly in the 
area of error handling, that are continually being refined to 
improve the system's operational efficiency. 
This last item is important in achieving the final 
high volume performance requirement. TIPS has achieved the 
stringent geometric rectification, temporal registration and 
radiometric correction performance requirements placed upon 
it. It is consistently and routinely producing extremely 
high quality. film and digítal products at specific levels. 
While TIPS is currentiy an operational system, it is stil] 
evolving toward the final operational product levels. There 
is every expectation that the operational enhancements to be 
implemented over the next few months will enable that goal to 
be successfully achieved. 
ACKNOWLEDGEMENTS 
The authors wish to recognize the exerptise and exemplary 
efforts of the General Electric Company personnel who 
developed the Landsat spacecraft's instrument module, 
integrated spacecraft systems and designed and developed the 
Landsat ground processing svstems. and of. the Hughes Aircraft 
Corporation personnel who designed and developed the MSS and 
TM instruments. ;