Description of Driving Event:
Use of Hardware Before Qualification Testing and the Use of Software Before Verification and Validation
Lesson(s) Learned:
Some hardware is being used in MEIT before it has completed qualification testing. Software is also often used before its verification and validation is complete. In both cases, modification to the hardware or software may be required before certification is completed, thereby potentially invalidating the results of the initial MEIT testing.
Recommendation(s):
When it makes sense to deliver hardware or software to system-level testing such as MEIT before qualification/certification is complete, the effect of any qualification-induced changes must be carefully evaluated for implications for regression testing. Final testing should always be run with validated software and qualified hardware.
Evidence of Recurrence Control Effectiveness:
NASA concurs with the recommendation and notes that the ISS Program requires regression evaluation for all modifications performed on flight hardware to assess whether certification, acceptance, or integration testing results are invalidated and must be performed again. The final flight configuration will be verified by regression testing as well as acceptance, mission sequence, end-to-end, and integration tests. The Space Station and Shuttle Payloads Office at KSC (Code NN) utilizes Flight, Flight Equivalent and GSE hardware and software for MEIT that has been certified through ISS Program Office control boards and panels for these tests. The boards and panels also specify regression tests with flight units when required through the directives they provide. The NN MEIT test schedules currently have regression tests planned for modified or repaired hardware units and revised software per ISS Program Office control board and panel directives and requirements.
Documents Related to Lesson:
N/A
Mission Directorate(s):
- Space Operations
- Exploration Systems
Additional Key Phrase(s):
- Aerospace Safety Advisory Panel
- Computers
- Risk Management/Assessment
- Software
- Test & Verification
- Test Article
- Test Facility
Additional Info:
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