High-altitude balloon missions enable aerospace technologies to be validated under stratospheric conditions using low-cost, rapidly developed platforms. This research presents the design, manufacture, and implementation of a 3D-printed structural capsule for the Zuyat Mission, developed at Universidad Don Bosco, El Salvador. The objective was to validate ABS as an accessible and suitable material for protecting electronic systems during an actual stratospheric mission. The design was based on previous research into near-space modules, including the STRATOS 1–3 models, material selection, manufacturing parameters, mechanical testing, and structural and thermal analyses. A CubeSat-inspired internal structure was retained and divided into levels to house the power system, onboard computer, sensors, and communications equipment. It was integrated into an external capsule, also manufactured from ABS using fused deposition modeling (FDM), to protect the systems, facilitate payload integration, and provide a suitable geometry for flight, descent, and recovery.ABS was selected for its availability, ease of manufacture, and better thermal stability and impact resistance compared with PLA. During the mission, the capsule housed positioning, computing, power, sensor, and radio-frequency systems. The probe reached a minimum pressure of approximately 8 hPa, equivalent to 32.7 km under standard-atmosphere conditions, exposing the structure to less than 1% of sea-level pressure and estimated temperatures near −43 °C. After ascent, parachute descent, and field recovery, inspection confirmed that the capsule survived without evident structural failure. These results support ABS-based FDM 3D printing as a viable option for university stratospheric missions and future near-space, Earth-observation, and aerospace capacity-building projects in Central America.