Safety

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.

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

Pyro deployment is optional and is the responsibility of the person assembling, testing, and flying the vehicle. AstroNav Nano documentation cannot determine whether a particular rocket, recovery system, charge, or launch environment is safe.

Follow the rocket, recovery-system, component, range, and local safety instructions that apply to your vehicle. If those instructions conflict with this page, stop and follow the stricter requirement.

Use only approved low-power hardware

Use only low-voltage, low-power pyro devices that are appropriate for AstroNav Nano and your recovery system.

Do not connect high-voltage, high-power, or otherwise unapproved ignition devices.

Deployment charge and parachute protection

When the design calls for a deployment charge:

• The charge normally belongs under the parachute, according to the specific recovery-system design.
• Use suitable fireproof cotton or paper to protect the parachute from heat, flame, and hot particles.
• Confirm that the charge location, containment, venting, and recovery layout match the instructions for the specific vehicle.
• Never assume that a layout is safe because it worked in another rocket.

Flash cotton can create enough pressure to open a parachute, but it can also ignite unexpectedly and cause burns, fire, or equipment damage.

Measure and validate every charge

Use a suitable scale and follow the approved procedure for your specific application. There is no universal safe amount of flash cotton; do not use a nominal value as a default or assume that a quantity that worked elsewhere is safe in your vehicle.

Measure, inspect, and document the charge before loading it. If you cannot verify the required amount and setup, do not arm or fly the system.

Testing and handling

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.

Keep flash cotton, E-matches, and other pyrotechnic materials away from heat, sparks, open flames, and sources of ignition. Handle them only when the system is unpowered and the area is prepared for the applicable safety procedure.

Final responsibility

This page provides general safety guidance, not approval for a particular design or charge. You are responsible for deciding how the hardware is used, complying with applicable rules, and confirming that the complete recovery system is safe before flight.

Using the pyro function

Use this workflow only after the vehicle-specific recovery design, charge procedure, and range requirements have been reviewed.

1. Configure and test while unpowered

• Install the battery and AstroNav Nano in the intended fixture, but keep all live pyro hardware disconnected.
• Set the flight-estimation and launch-detection values in the configuration. These values determine when flight events, including apogee, are recognized.
• Choose a launch-detection threshold that is safely above expected vibration and handling noise. Do not set it close to 1 g; a value such as 2 g is not universally safe or correct. Validate the threshold against the specific vehicle and flight.
• Complete configuration, firmware, and sensor checks with the pyro output physically isolated.

Do not skip flight estimation

Accurate flight-estimation data is required for reliable event detection. Incorrect values can cause events such as apogee deployment to be detected too early, too late, or not at all.

2. Prepare the recovery system separately

• Use only the approved low-voltage, low-power pyro device and charge procedure for the vehicle.
• Prepare cable lengths and insulation for the specific installation, keeping conductors protected from abrasion, heat, and moving recovery hardware.
• Measure the charge with a suitable scale and use the vehicle-specific amount and containment method. Do not improvise a charge or treat a nominal amount as a universal recipe.
• Keep the parachute protected with the approved fireproof material and confirm that the charge is positioned according to the recovery-system design.

This documentation does not provide instructions for assembling, wrapping, or loading a live flash-cotton charge. Follow the instructions from the qualified recovery-system or range authority responsible for the vehicle.

3. Arm only after the vehicle is closed up

1. Complete the Getting started power-on and configuration workflow.
2. Confirm that the launch-detection and flight-estimation settings are the intended values.
3. Keep the vehicle pointed and handled safely while the board is powered.
4. Connect the approved pyro wiring only when the vehicle is otherwise ready and the launch area procedure permits it.
5. Place the recovery system in its intended order and close the vehicle according to its design. Verify that cables are not pinched and that the parachute can deploy freely.
6. Perform the final Pre-flight checks before launch.

Powered means armed for movement

Once AstroNav Nano is powered and in its flight-ready state, it is waiting for launch detection and may activate the pyro output when its configured conditions are met.

Move the powered vehicle slowly and deliberately. Avoid sudden motion, impacts, or abrupt changes while handling it. If anything is incorrect or unexpected, stop, isolate the vehicle, and remove power only when it is safe to do so.

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.