CO₂ Cold Gas Thruster

Goal

Design a 250 N cold gas thruster with a conical nozzle, sized for sea-level operation, and produce a physical model.

Sizing the nozzle

• Sized throat and exit geometry from isentropic flow relations for sea-level operation
• Calculated choked mass flow, exit velocity, and specific impulse across a 6.4 area expansion ratio
• Arrived at a specific impulse of 58 s

Choosing the contour

The contour was a trade between performance and length. An 80% Rao bell performs better, but it would not meet the packaging length requirement, so the design uses a 14° conical contour instead, accepting a 1.5% divergence loss.

Build

Modeled the assembly in Autodesk Fusion and printed a full-scale model in nylon 12 via SLS.