1. The Canterbury’s ribs

James S. A. Corey’s The Expanse describes the Canterbury as a massive ice hauler built to take the slow, steady abuse of long transits. Its structure is not elegant; it is overbuilt. The series treats that overbuilding as background. For the desktop, overbuilding is a cost. The launch-environment literature is the discipline that tells us how much overbuilding is enough.

This entry applies that literature to the desktop’s rack and cell assembly.

2. The desktop’s launch-load path

A desktop cell sitting in its rack during launch is a mechanism under load. The launch vehicle transmits vibration and shock through the spacecraft structure, into the rack, and into the cell. The cell is held by rails, retained by a latch, and connected by blind-mate connectors. Each of these interfaces is a potential failure point.

The literature says the same thing about every mechanism: if you do not test the assembled configuration, you do not know the load path. A cell tested by itself may pass; a cell tested inside the rack may fail because the rack changes its boundary conditions.

3. What the literature recommends

  • Test the assembly, not just the parts. The rack and cell together are the unit of interest.
  • Test with the cell inserted and retained. An empty rack is a different structure than a loaded one.
  • Include shock as well as vibration. Separation events are short and severe; they can release latches and back out connectors.
  • Monitor continuity and resistance during test. A connector that passes before and after vibration but opens during vibration is a failure.
  • Allow notching and force limiting, but document why. Tailoring is legitimate; guessing is not.

4. The most likely failure modes

For the desktop, the likely failure modes under launch loads are:

  • Latch opening: retention must be positive-locking, not just spring-loaded.
  • Connector fretting: micro-motion at the electrical interface can increase contact resistance.
  • Rail slip: if the cell can move relative to the rack, the thermal interface degrades.
  • Local resonance: a cell or sub-assembly may have a resonance within the random vibration band, amplifying the load.

5. What this changes

  • The vibration and shock qualification test is now a required step for the rack and cell assembly.
  • The test article must include a representative cell, fully inserted and retained.
  • Continuity and contact resistance should be monitored during the test.
  • The next entry closes the arc and records the decided posture.