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Case Study of Using High Performance Commercial Processors in SpaceThe purpose of the Space Shuttle Cockpit Avionics Upgrade project (1999 2004) was to reduce crew workload and improve situational awareness. The upgrade was to augment the Shuttle avionics system with new hardware and software. A major success of this project was the validation of the hardware architecture and software design. This was significant because the project incorporated new technology and approaches for the development of human rated space software. An early version of this system was tested at the Johnson Space Center for one month by teams of astronauts. The results were positive, but NASA eventually cancelled the project towards the end of the development cycle. The goal to reduce crew workload and improve situational awareness resulted in the need for high performance Central Processing Units (CPUs). The choice of CPU selected was the PowerPC family, which is a reduced instruction set computer (RISC) known for its high performance. However, the requirement for radiation tolerance resulted in the re-evaluation of the selected family member of the PowerPC line. Radiation testing revealed that the original selected processor (PowerPC 7400) was too soft to meet mission objectives and an effort was established to perform trade studies and performance testing to determine a feasible candidate. At that time, the PowerPC RAD750s were radiation tolerant, but did not meet the required performance needs of the project. Thus, the final solution was to select the PowerPC 7455. This processor did not have a radiation tolerant version, but had some ability to detect failures. However, its cache tags did not provide parity and thus the project incorporated a software strategy to detect radiation failures. The strategy was to incorporate dual paths for software generating commands to the legacy Space Shuttle avionics to prevent failures due to the softness of the upgraded avionics.
Document ID
20090039502
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Ferguson, Roscoe C.
(United Space Alliance Cape Canaveral, FL, United States)
Olivas, Zulema
(United Space Alliance Cape Canaveral, FL, United States)
Date Acquired
August 24, 2013
Publication Date
November 10, 2009
Subject Category
Avionics And Aircraft Instrumentation
Report/Patent Number
JSC-CN-18675
07ATC-243
Meeting Information
Meeting: SAE AeroTech Congress and Exhibition
Location: Seattle, Washington
Country: United States
Start Date: November 10, 2009
End Date: November 12, 2009
Sponsors: Society of Automotive Engineers, Inc.
Distribution Limits
Public
Copyright
Other

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