1. The narrow range, one more time
Michael Crichton’s The Andromeda Strain builds tension around equipment that assumes a narrow band of conditions. The lesson, repeated across entries 387 and 397 through 399, is that an experiment designed only for nominal conditions can miss the failure mode that matters. The desktop’s attachment interface will not see nominal conditions in orbit. It will see vibration, thermal distortion, wear, and placement error. The off-nominal alignment test is the antidote to that narrowness.
Entries 397 through 399 defined why the test matters, what the matrix is, and what success looks like. This entry closes the arc.
2. What was decided
The next room-temperature test after the nominal attachment interface test will be the off-nominal alignment test. The test will apply deliberate translation and tilt errors to the cell before insertion, using a matrix derived from the tolerance stack-up. Pass criteria require full seating, reliable electrical and thermal contact, no damage, and extraction without excessive force.
3. What this test protects against
The test protects against three real risks:
- False confidence from a nominal-only test: a design that works perfectly when aligned may fail in operation.
- Tolerance stack-up surprises: individual tolerances that are within spec can combine into an out-of-spec condition.
- Operational reality: robots and humans make placement errors. The interface must tolerate them.
4. What comes next
If the off-nominal alignment test passes, the interface is ready for the thermal-vacuum campaign. If it fails, the guide features, connector compliance, or thermal interface need redesign before the more expensive environmental test.
5. What this changes
- The off-nominal alignment test arc is closed.
- The test plan is explicit and ready to execute.
- The cycle decided in Entry 388 is now complete: reading, wondering, and testing have all been addressed.