A newly designed decoupling method for micro-Newton thrust measurement

Area of Science:

• Aerospace Engineering
• Mechanical Engineering
• Physics

Background:

• Accurate micro-Newton thrust measurement is crucial for spacecraft propulsion system development.
• Traditional methods often suffer from environmental and system-induced disturbances, limiting precision.

Purpose of the Study:

• To propose and validate a decoupling method for micro-Newton thrust measurement using a torsion pendulum.
• To minimize influences from propellant tubes and electrical connections on thrust measurements.

Main Methods:

• A torsion pendulum system was designed using a hollow aluminum tube for propellant transport and pendulum suspension.
• The thruster's control box was mounted on the pendulum, powered via a liquid metal conductive unit and controlled wirelessly.
• Error sources were analyzed to quantify measurement uncertainty.

Main Results:

• The proposed design significantly reduced disturbances from the propellant tube and wires.
• Improved stability of the torsion spring constant was achieved.
• The expected three sigma uncertainty for cold gas thruster measurement was determined to be 0.03²+(0.10%*F)²μN.

Conclusions:

• The developed decoupling method enhances the precision and stability of micro-Newton thrust measurements.
• This approach is suitable for accurate characterization of small-scale propulsion systems.
• The integration of wireless control and liquid metal conductive units offers a robust solution for minimizing measurement coupling.