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Requirement | Reason | Verification |
|---|---|---|
Track Rocket Location | Aid in Recovery of the Rocket | Test |
Gather Data: Altitude, Acceleration, Velocity | Verify success of reefed parachute and collect information about the rocket’s performance | Test |
Provide Ejection Signals to the Smoke Flare, Deployment Charges | Ensure safe descent of the rocket and ignition of smoke flare | Test |
Flight Computers are Redundant and Independent | Ensure that the flight computers and e-matches work in case of a single failure | Design |
URRG Requirements
Describe what an external organization (probably ESRA, URRG, or EH&S) requires of this one.
Requirement | Reason | Verification |
|---|---|---|
All components of the rocket must be safely recovered, and no part of the rocket can be intentionally ballistic | Safety | Design |
Interface Requirements
Describe what other subsystems require of this one.
Source(s) | Requirement | Reason | Verification |
|---|---|---|---|
Recovery | Smoke Flare Deploys | Send deployment signals to the smoke flare for recovery of the rocket | Test |
Recovery | Deployment Signal to Deployment charges | Successfully deploy the parachute | Test |
Structures | Structures Polycarb Interface (Difference of inner diameters of 3.85” and 3.5”) | Ensure Avionics Bay fits in the rocket and does not interfere with other sections | Design |
Design
This should describe high-level distinguishing features of this subsystem. If this project is recurring (Space Race or IREC), focus on the items you judge would be important to tell the next year's team, especially specific improvements over previous years.
The Avionics Bay used 2x Eggtimer Quarks powered by 2x 7.4V 2000mAh Li-ion Batteries. The flight computers were wired entirely independently.
For tracking, the Avionics Bay used 1x Eggfinder Mini TX powered by 1x 7.4V 2000mAh Li-ion Battery to transmit signals from the rocket, and 1x Eggfinder Dongle RX connected to a laptop to recieve signals on the ground.
For Data Logging, the Avionics Bay used 1x Adafruit Feather M0 Adalogger powered by 1x 3.7V 2000mAh Li-ion Battery. The datalogger system utilized two breakout boards, 1x Adafruit BME280 to record temperature and pressure (and thereby altitude) and 1x Adafruit ICM-20948 9-DoF IMU to record acceleration, rotation, and orientation. All data recorded would be written to 1x 4GB microSD Card hot glued into the mainboard.
Post-mortem
Due in part to the catastrophic nature of the rocket’s launch, the only avionics system operating when the rocket was launched was the tracking system.
Despite the unanticipated forces applied to the avionics bay during the flight, the tracking system continued operating through its entirety, eventually successfully reporting the final coordinates of the avionics bay (42.700473°, -77.194522°).
Over the course of the flight the avionics bay experienced multiple structural failures. The most important to note is that several of the battery mounts sheared off such that they no longer constrained the Li-ion batteries. This is potentially due to the orientation of the layer lines in the 3D prints combined with the higher than anticipated forces. It is worth examining layer line orientation in the future to reduce the chances of loose Li-ion batteries in rocket, successful or not. The attachment keeping the avionics bay constrained to the polycarb tube also sheared, though this is likely due primarily to the higher than anticipated forces, and likely could not have been reasonably mitigated.
In ProgressAside from flight complications, assembly of the avionics bay should have been given more design considerations. Some screws and nuts were placed in tight spaces, making accessing them for assembly and disassembly difficult, though not impossible.
Additionally, integration of the avionics bay with the rest of the rocket should also have been given more design considerations, as integration while the e-matches were connected was difficult, though again not impossible.
In the future, when evaluating whether or not to turn off avionics system:
It must not be done while the igniter is still in the motor.
The decision should be made in the context of the battery life of the avionics systems contrasted with the expected delay.
Structures
Structures Requirements
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