| Tier | Scope | Instrument | State |
|---|---|---|---|
| 0 | Instrument self-checks | Calibrator, loop-back, reference sensors | Next |
| 1 | Benchmark A — the air tube | Two measurement microphones, 192 kHz | Frozen · awaiting hardware |
| 2 | Coupled air and solid | Characterised panel on the tube | Locked until Tier 1 passes |
| 3 | Ground and site | Three-component seismometer | Designed |
| 4 | Atmosphere | Outdoor microphones, weather station | Designed |
| 5 | Magnetic field | Fluxgate magnetometer | Designed |
| 6 | Structure acoustics | Room measurement chain; published scale models | Designed |
| — | Replication | Other people's instruments | Always open |
From the bench to the field, in order
Each tier begins only when the one before it has produced a sealed result. Hardware is acquired only for the next tier. Nothing in this program is a physical result yet.