1. The explosion that teaches

Ignition! treats explosions as data. A propellant that detonates in the test stand is a failure as a product but a success as an experiment because it tells the chemist where the boundary is. The propulsion test campaign for the desktop needs the same discipline. A test that fails cleanly, with good data and no injury, is more useful than a test that passes for the wrong reason.

2. Clear successes

  • Thrust matches the prediction within tolerance.
  • Leak rates are below the maximum allowable.
  • Valves respond within specification across the thermal range.
  • The platform remains stable and controllable during and after firing.
  • Autonomous sequences execute correctly and ground override works at every stage.
  • EMI levels are below the subsystem susceptibility limits.
  • Plume effects are within the contamination budget.

3. Clear failures

  • Any leak that cannot be explained and bounded.
  • A thruster that fails to start or fails to shut down on command.
  • A firing sequence that cannot be aborted by ground.
  • A burn that causes an unrecoverable attitude excursion.
  • EMI that disrupts communications, compute, or power regulation.
  • Any event that would have created a hazard if it had occurred on orbit.

4. The gray zone

Some results are not passes but are not clear failures either:

  • Thrust slightly below prediction but within a range that can be compensated by longer burns.
  • Higher than expected power draw that still fits the budget.
  • Minor plume deposition on a surface that can be tolerated or cleaned by design.

These are engineering decisions, not test outcomes. They must be closed with analysis, redesign, or a waiver before flight. The test team should not be pressured to call them passes.

5. What success really looks like

Success is not a green checklist. Success is a team that can explain, with data, why the propulsion subsystem will behave as expected in orbit and what it will do when it does not. If the campaign ends with that explanation, the desktop can carry a rocket with confidence.