An elastic pendulum thrust stand for evaluating six-degree-of-freedom thrust of 10 mN-class propulsion systems

Area of Science:

• Aerospace Engineering
• Mechanical Engineering
• Spacecraft Propulsion

Background:

• Accurate measurement of six-component thrust vectors is critical for advanced CubeSat missions.
• Propulsion systems can generate unintended thrust and torques, impacting mission quality.
• Conventional thrust stands face limitations in measuring low-thrust (mN class) propulsion systems.

Purpose of the Study:

• To propose and demonstrate an elastic pendulum six-degree-of-freedom thrust stand for CubeSat propulsion systems.
• To overcome the limitations of conventional thrust stands in measuring low-thrust components.
• To enable precise measurement of all thrust and torque components.

Main Methods:

• Designed an elastic pendulum six-degree-of-freedom thrust stand utilizing springs to support the propulsion system.
• Improved the effective thrust-to-weight ratio to enhance sensitivity for low-thrust measurements.
• Implemented a null-balance method with six voice coil motors for precise six-degree-of-freedom thrust measurement.
• Performed mechanical characterization of the stiffness matrix to confirm linearity and functionality.

Main Results:

• Demonstrated the thrust stand's capability by measuring a 10 mN-class cold-gas thruster.
• Achieved measurement uncertainties within 0.82 mN for thrust vector components.
• Attained measurement uncertainties within 0.13 mN·m for torque components.
• Uncertainties were rigorously derived using propagation analysis.

Conclusions:

• The proposed elastic pendulum thrust stand effectively measures six-component thrust vectors for CubeSat propulsion.
• The novel design significantly improves measurement accuracy for low-thrust systems.
• This technology is vital for ensuring high-quality thrust and torque performance in CubeSat missions.