1. Exploring the unknown with instruments, again

Arthur C. Clarke’s Rendezvous with Rama returns because the power bus is another alien environment entered with instruments and stopping rules. The test team applies loads, injects faults, and watches the bus respond. Success is not defined by reaching the end of a script; it is defined by learning that the bus can survive the cases that matter.

This entry defines success and failure for the power distribution test.

2. Minimum success

The power distribution system passes if, for every case in the matrix:

  • The bus voltage remains within the operational band.
  • No cell exceeds its rated current, temperature, or state-of-charge limits.
  • Faulty cells or loads are isolated before the bus collapses.
  • Critical loads continue to receive power during and after faults.
  • Telemetry accurately reports the state of every cell and switch.
  • The system returns to a stable, known state after the fault is cleared.

This minimum says the power bus is safe and functional under the expected range of conditions.

3. Full success

A stronger result would add:

  • Transient voltage droop during load steps stays within tight margins.
  • Cell reconnection after isolation is seamless.
  • Load shedding follows the exact priority order defined by operations.
  • The autonomous response matches the ground-commanded response.
  • The test article is fit for additional integrated testing without rework.

This stronger result supports a claim of margin and predictability.

4. Failure modes

The test fails if any of the following occur:

  • The bus voltage collapses during a single-cell fault.
  • A faulty cell or load is not isolated within the required time.
  • A critical load loses power due to a non-critical fault.
  • A cell is damaged by overcurrent or overvoltage.
  • The software deadlocks or enters an undefined state.
  • Telemetry misrepresents the actual bus state.

Each failure mode points to a fix: faster switches, better current limits, revised load priorities, or a more robust state machine.

5. What this changes

  • The power distribution test has clear pass and fail criteria.
  • The criteria separate safety from performance.
  • The next entry will close the power distribution test arc.