# Safety

:::danger[Ignition and deployment hardware]

AstroNav Nano controls hardware that may be capable of ignition or deployment.

Read this section before connecting batteries, payloads, pyro circuits, servos, or launch hardware.

:::

## General safety

Always:

- Treat the pyro output as capable of ignition whenever the board is powered.
- Keep hazardous loads disconnected while configuring the board.
- Keep hazardous loads disconnected while flashing or troubleshooting firmware.
- Inspect battery polarity and voltage before applying power.
- Inspect wiring and connectors before flight.
- Secure the board correctly before launch.
- Verify your output-inhibit strategy.
- Review configuration changes before using them in flight.

:::caution[Complete vehicle readiness]

A healthy board state does not by itself mean the vehicle is ready to launch.

Flight readiness must include the complete vehicle, wiring, recovery system, power system, launch hardware, and applicable operating procedures.

:::

## Pyro output

:::danger[Pyro output]

Never connect an igniter, deployment charge, motor initiator, or similar hazardous load while testing configuration or firmware.

The `PYROTEST` command can energize the pyro output.

Do not use `PYROTEST` with a live pyro circuit.

:::

## During development

Keep the board physically separated from launch hardware while:

- Building firmware
- Uploading firmware
- Editing configuration
- Calibrating sensors
- Testing USB behavior
- Monitoring serial output
- Investigating faults

## Unexpected behavior

If something unexpected happens:

1. Disconnect hazardous hardware.
2. Remove power when safe.
3. Inspect the configuration.
4. Inspect wiring and power.
5. Review serial and debug information.
6. Find the cause before continuing.

Do not work around unexplained faults simply to continue testing.