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- Fault Tolerant Satellite Systems: SoHaR is developing operating system extensions
to enable adaptive fault tolerance to be applied in real time satellite control.
This demanding environment must account for changes in both mission requires (e.g.,
when to optimize power consumption vs. recovery time) and the failure and recovery
characteristics of the individual system.
- Fault Tolerant Robotics for Spaceborne Applications: Under contract to the NASA
Jet Propulsion Laboratory, SoHaR has developed software techniques to implement
fault tolerance in robots used for applications such as the Space Station.
- Spaceborne Failure Data Analysis: Under contract to the NASA Langley Research Center,
SoHaR investigated failure data from major NASA programs in order to assess overall
trends, identify strengths and weaknesses, and make recommendations for design,
qualification, and analysis requirements in future NASA programs for increasing
mission reliability.
- Fault Tolerant Software Development: As part of research to support the Strategic
Defense Initiative (SDI), SoHaR conducted two separate efforts to demonstrate and
apply a methodology for producing fault tolerant software for spaceborne applications.
- Reliability Modelling for Spacecraft: Under a subcontract in support of SDI, SoHaR
developed a reliability model which includes sparing and can be integrated into
a Fleet Effectiveness model.
- Spaceborne Electronic Component Reliability Prediction: Under contract to the U.S.
Air Force Rome Air Development Center (RADC), SoHaR demonstrated that in most cases
a decreasing hazard model is more appropriate for space applications than the conventional
constant hazard one. The work, which resulted in several articles and technical
reports, also proposed procedures which were incorporated into MIL-HDBK-217E for
spaceborne electronics.
- Design Concepts for Reliable Spaceborne Mini- and Microcomputers: SoHaR assisted
a major aerospace contractor in the development of design concepts for a new line
of spacecraft computers that emphasize fault tolerance and self-test.
- Analysis of Flight Control Software Faults: Under several contracts with NASA centers,
SoHaR analyzed fault data from the Space Shuttle and a number of flight control
development efforts. Results of the analysis are used to arrive at meaningful fault
classifications and to formulate "lessons learned" for future development efforts.
- Software Failure Analysis: Under a subcontract to the Jet Propulsion Laboratory,
SoHaR conducted an analysis and classification of software failures on a major satellite
data communication system including classification of the probable cause of the
failure and the program phase in which the fault occurred.
- Fault-Tolerant Spaceborne Computer: SoHaR supported the U.S. Air Force in their
efforts to develop a general purpose fault tolerant spaceborne computer. Specific
SoHaR tasks in this multi-year project were Element Reliability Assessment, Fault
Tolerance Evaluation, Review of Specification Compliance, and Evaluation of User
Reliability Requirements.
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