Flight states

AstroNav Nano uses a controlled state machine throughout startup and flight.

State overview

flowchart TD
    boot[Booting] -->|USB power| usb[USB Mode]
    boot -->|Flight startup| calibration[Calibrating]
    usb -->|Leave USB storage mode| calibration
    calibration --> idle[Idle]
    idle -->|Launch confirmed| boost[Boost]
    boost --> coast[Coast]
    coast -->|Apogee confirmed| descent[Descent]
    descent -->|Settled| landed[Landed]
    boost & coast -.->|Bump, no real climb| idle
    boot & calibration & idle & boost & coast & descent -.->|Critical fault latched| fault[Fault]
    class fault danger-node

Descent is always entered at apogee. Whether the pyro fired depends on FIRE_PYRO_APOGEE and the safety conditions in Flight operation. A latched critical fault disables the pyro output; investigate its cause before continuing.

Booting

The board initializes:

• Hardware
• Sensors
• Storage
• Status systems

Outputs are kept in a safe startup state.

USB Mode

When the board detects USB power, it exposes its storage to the connected computer.

This allows access to:

• Settings.ini
• Howto.txt
• Flight logs
• Diagnostic information

Calibrating

Before flight, AstroNav Nano establishes:

• Gravity reference
• Gyroscope bias
• Baseline pressure

The board must remain stationary during this process.

Idle

Calibration has completed and the board is waiting for launch conditions.

Boost

Sustained acceleration has confirmed launch and powered ascent.

A bump is not a flight

If a knock while handling the rocket is taken as a launch, the board returns to Idle once it is at rest again, as long as it never climbed 3 m. It stays ready for the real launch, and nothing is written to /logs.

Coast

Powered ascent has ended while the vehicle remains in flight.

Descent

Apogee has been confirmed. This state is entered at every apogee, also when the pyro is disabled or blocked.

The pyro fires at most once per flight. Whether it fired, and if not why, is recorded in the flight log.

Landed

The vehicle has remained stable long enough for the firmware to confirm landing.

The firmware then finalizes the mission log and updates flight records.

Fault

A critical problem has been detected.

When a critical fault is latched:

• The system enters a safe state.
• The pyro output is disabled.
• The cause must be investigated before continuing.

Status LED

Each state has its own colour. Breathing = waiting on the ground, solid = in flight, blinking = needs your attention.

State	LED
Booting	White, breathing
USB Mode	Blue, breathing
Calibrating	Yellow, blinking: keep the board still
Idle	Green, breathing: ready for launch
Boost	Orange, solid
Coast	Purple, solid
Descent	Cyan, solid
Landed	Magenta, blinking
Fault, low battery or sensor fault	Red, fast blinking

What you will typically see

Situation	Sequence
Power-up on battery	White → yellow → green
Power-up on USB	White → blue (after eject: yellow → green)
Flight	Green → orange → purple → cyan → magenta
Bump on the pad	Green → orange → purple → green

Magenta on the pad

If the LED blinks magenta without a flight, the board was carried 3 m or more after a bump and now considers the flight over. Power-cycle it and let it calibrate again before launch.

Do not use the LED alone for detailed diagnostics.

Use the USB debug information and serial output to investigate warnings and faults.