SEB Recovery System

This recovery system is a single separation dual deployment system with a similar architecture to our spaceshot recovery system and was heavily inspired by other high performance rockets in the amateur rocketry community. All components were designed to be space and mass efficient, fitting the drogue and main parachutes and a packed avionics bay with dual redundant commerical flight computers and tracking modules, in addition to custom live video and telemetry hardware, within the nosecone. A metal coupler was used as a separation point for nosecone ejection and a structural component to retain the forward closure of the motor and take bending loads during flight. The parachutes and shock cord are packed in the fiberglass chute cannon and coupler, an approach that prevents early deployment of the main parachute and efficiently utilizes available nosecone volume, as the annulus around the chute cannon is utilized to mount antennas for live video transmission. Recovery loads run through the a structural fiberglass G10 avionics sled and the nosecone tip, rather that using the more common method of running a threaded rod through the avionics bay, in order to keep those areas fully radio frequency transparent. 

With SEB's less-than-ideal recovery record (only one previous nominal recovery), I was determined to overhaul the way we characterized all aspects of our recovery systems, from mechanical components to avionics. I devised a testing plan and month-long timeline to bring up this new recovery system with rigorous testing and qualification.

Testing started with the smallest but most impactful component: charges. Black powder pyrotechnic charges are a commonly used and highly reliable form of ejection, and with research and precedents from other high altitude flights, we tested several configurations, finally settling on using high length-to-diameter ratio vinyl tube charges. Before conducting any integrated ejection tests, I also characterized packing volumes for both the main and drogue parachutes in their proposed configurations to ensure all necessary components would fit inside the nosecone as intended and revamped parachute folding procedures, which had caused recovery issues on rockets launched in the past. 

After individual components were characterized, we moved into subsystem qualification by testing main ejection and drogue ejection individually. This allowed us to determine the amount of black powder needed in our charges to deploy parachutes without fault and helped to identify possible tangling issues that could arise in flight. After all mechanical subsystems were successfully tested, we moved into fully integrated system acceptance ground testing with flight computers armed and all parachutes and shock cord packed. With three tests in a row of nominal deployment from flight computers and no unintended damage of components, we were ready to fly. 

On December 7, 2024, we launched LADHAD to test this recovery system. Unfortunately, due to an anomaly in which the AIM XTRA flight computer failed to detect launch and subsequently did not fire any of the charges, we did not recover. However, since a significant portion of the hardware from the failed recovery was able to be salvaged and reused, and no major mechanical or structural changes needed to be made to the rocket, we decided to relaunch the rocket at the beginning of Spring 2025. To resolve the issues we experienced with recovery avionics, we implemented a small form factor Blue Raven to use alongside the AIM XTRA for avionics dual redundancy and reaccepted the full recovery system for flight. 

We finally launched LADHAD 2 on March 1, 2025 and successfully recovered the rocket, marking the second nominal recovery in the history of SEB. With a functional recovery system, we hope to use a scaled up version of this recovery system on all future SEB rockets, from aerostructures testbed vehicles to liquids at high altitudes.