Investigation of Controlled Aerodynamic Descent for Xaero-B
Shortly after starting with Masten I was approached about investigating concepts to extend the flight altitude of Xaero-B, a vehicle that was already well into construction. Of particular interest was the prospect of turning off the main engine during decent in order to conserve fuel. The main engine is the sole means of yaw and pitch control so another means of control would be necessary. Early analysis showed that Reaction Control Thrusters would be too massive. A design for aerodynamic drag flaps made it through initial analysis and reviews including 20th scale water drop tests. As Technical Primary Investigator, I developed a third scale model with autonomous control of the drag flaps and recovery parachutes. This model went through iterations during 12 drop tests from an airplane and ultimately tested descending from 35km. The tests showed that the design was stable during uncontrolled descent in a relevant environment and that active control had sufficient authority over descent heading.
25klbf Dual Cryogen Test Stand and Campaign
In 13 months we built a new 25klbf-thrust test stand and tested the largest additively manufactured engine at the time. I designed the instrumentation, wrote the control code, and operated the console for all checkout and hot fire tests. The program built on much of our previous work and as expected the increase in scale caused new phenomenon to arise. The engine design was unique which required new instrumentation and control laws to ease the concerns of the propulsion engineers.
Avionics and software design for reusable VTVL rockets
I have the pleasure of collaborating with engineers in the design, fabrication, and testing of highly reusable vertical takeoff and vertical landing (VTVL) rockets. The high frequency of flights, as many as five in a day and ten in a week, demands a resilient design. I work to develop new sensor failover logic and vehicle health monitoring algorithms. These changes are validated in Monte Carlo and hardware-in-the-loop simulations, before moving on the tethered flights and ultimately free flight operations.
7klbf Hypergol Test Stand and Campaign
In an effort to develop storable propellant combinations for in-space propulsion I developed control, instrumentation, and procedures for a hypergolic test stand. Dealing with hypergolic propellants presents many challenges in terms of personnel safety. Vehicle control and autonomous behaviors needed to be thoroughly scrubbed through and redesigned with appropriate safeguards. The test campaigns revealed many intricacies in hypergolic engines that were carefully teased out and overcome.
I have been fortunate enough to find professional work that is challenging and aligns with my interests. The personal projects I have time for include instrumentation and actuators on a friend's E-Racer build, tiltrotor quadcopter for testing control algorithms, CNC routed terrain contours for homemade gifts, and cutting/welding a friend’s Scion XB into a pickup.