1. The test that saves the programme
Apollo 13 is remembered for the in-flight failure, but the ground tests before launch were equally important. They exposed problems that could have been fatal if discovered later. A test that fails early is often the test that saves the mission.
This entry imagines what happens if the attachment interface ground test fails.
2. What failure means
Failure means the cell cannot be inserted, cannot seat, cannot connect, or cannot repeat the operation within specification. The failure could be in any of the four physics domains:
- Mechanical: the cell jams, the latch fails, or the alignment is too tight.
- Thermal: the interface resistance is too high or too variable.
- Electrical: the connector does not mate reliably or overheats.
- Data: the link does not come up or drops out under vibration.
The most useful failure is the one that is clear and repeatable. A flaky failure is harder to fix than a clean one.
3. Why failure is valuable
From a Popperian perspective, a failed test is progress. It eliminates a wrong design before money is spent on flight hardware. The programme learns what does not work, which narrows the space of what might work.
Failure is expensive only if it happens late. A ground test that fails in the first phase is cheap.
4. The response options
If the test fails, the options include:
- Adjust the design: larger alignment features, better thermal interface material, different connector.
- Relax the requirements: accept higher thermal resistance if the cell can handle it.
- Change the architecture: move from sliding to a different insertion scheme, or add an active alignment stage.
- Run more tests: isolate the failure mode before redesigning.
The right response depends on which domain failed and why.
5. What this changes
- A failed test is treated as useful information, not a disaster.
- The response is to isolate the failure mode and redesign.
- The programme’s flexibility is tested as much as the hardware.