Mario Hernandez — Projects

Longhorn Rocketry Association · Vehicle design

Modeled the full vehicle assembly in Fusion 360 — ogive nose cone, body tube, motor tube with centering rings and motor retainer, bulkhead, thread-insert ring, rail buttons, and four tail fins.
Integrated four forward canards on servo-driven mounts, with the servos, servo casings, horns and canard plates modeled in place for active flight control.
Sized the airframe at 3 in diameter — the envelope the TVC flight computer below was compacted to fit on its avionics sled.

3 inBody diameter

≈ 32 inOverall length

4Active canards

Side profile — forward canards and aft tail fins on the 3 in body tube.

Longhorn Rocketry Association · Avionics

Ported the team's flight-computer design from EasyEDA into a hierarchical KiCad project (Power, USB/Reset, Processor, Sensors and Pyro sheets), cross-checking every net against the original schematic and board files.
Reworked the outputs for active control: eight actuator headers — TVC pitch and yaw, four fins, airbrake and reaction wheel — fed from a dedicated servo battery bus kept separate from logic power, plus two pyro channels with continuity check.
Compacted the board from 65 × 80 mm to 50 × 76 mm on four layers with a solid ground plane so it mounts lengthwise in a 3 in airframe; the IMU sits at the board centre and the ESP32 antenna at the edge over a copper keep-out.
Replaced the power stage with a 2 A synchronous buck (AP63205), moved the shift registers to 74HCT595 to fix a 3.3 V-to-5 V logic-level problem on the pyro gates, and added an external arming switch.
Fully routed with zero unconnected nets and zero copper-clearance errors in KiCad DRC; design complete, ahead of fabrication.

50 × 76 mmBoard size

4Copper layers

8 + 2Actuator + pyro channels

IREC Competition Rocket · Longhorn Rocketry Association

Designed an active airbrake system to shed roughly 2,500 ft of apogee and hold a 10,000 ft target altitude.
Selected a cam-slot actuation mechanism through trade studies favoring simplicity, low mass, and flight heritage.
Ran ANSYS Fluent CFD and Static Structural FEA to size aerodynamic loads and structural margins.
Ran transient CFD to capture oscillating vortex shedding on the airbrake bluff plate near Mach 1, extracting drag coefficient and drag force time histories across Mach 0.6–0.9 to validate the design.
Supported prototyping and test planning, refining tolerances, materials, and system integration.

SF > 2Structural margin

2,500 ftApogee reduction

IREC Competition Rocket — target apogee 2,000 ft, max velocity 110 m/s

Given three months to design an actuating fin system compact enough for a 3" body diameter, robust enough for high-speed aerodynamic loads, and light enough to protect the altitude target.
Ran a trade study weighing a linkage-based mechanism against a tab-based design; selected the tab design for fewer failure points, lower mass, easier control integration, and better scalability.
Built and maintained the CAD model in OnShape — a 14 mm-thick fin tab with an embedded slim servo, epoxied servo horn, and a dowel rod supporting rotation on the opposite side.
Used ANSYS CFD to find worst-case loading (tab actuated to 45°, 10x normal deflection) — 5,500 Pa static pressure, 2.6 N drag force, 1.25 drag coefficient.
Fed those loads into an FEA study confirming the dowel rod would see only 5 N under load, for a factor of safety greater than 6.
Calculated 30 N·mm of servo torque from drag loading against a rated 1,000 N·mm back-drive threshold, then bench-tested the servo (measured 1.08 N·m vs. 1.82 N·m stated max) to confirm it would not back-drive in flight.

FOS > 6Dowel rod margin

2.6 NDrag force

5,500 PaStatic pressure

Longhorn Rocketry Association — Advanced Research

Works on the mechanical subteam to control an aerodynamically unstable rocket by directing engine thrust.
Designed and modeled a 2-axis gimbal TVC assembly in SolidWorks, simulated in OpenRocket for active thrust steering and in-flight attitude correction.
Ran ANSYS Static Structural FEA (equivalent von Mises stress) on the gimbal ring, iterating the design to stay within material stress limits.
Designed safety features so the rocket cannot aim toward the ground in the event of a mechanical failure.

Propulsion Testing · LRA

Designed and assembled a steel static-fire test stand for solid rocket motors, engineered to withstand H-class thrust levels (~150 lbf).
Designed the ignition and control electronics in KiCad for safe, remote motor ignition.

~150 lbfRated thrust

UT Austin ECE Research, under Prof. Michael Becker

Wrote code to parse and analyze large molecular-dynamics configuration files (.cfg) from LAMMPS simulations.
Generated strain density functions to characterize deformation in Al₂O₃ particles at the atomic scale.
Examined how impact velocity and crystal orientation change resulting shear-strain distributions.
Visualized simulation output in OVITO and processed results in MATLAB to identify strain concentration patterns.