Office of Technology Transfer – University of Michigan

Spacecraft Satellite Attitude Control using Magnetic Torque Rods with Low Residual Magnetic Field and High Linearity

Technology #6772

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Researchers
Steven Rogacki
Managed By
Brian Copple
Assistant Director, Physical Sciences & Engineering (734) 615-8965

Torque rods are used by spacecraft in low earth orbit to exchange rotational momentum with the earth in order to control the orientation or attitude of the spacecraft. An orthogonal set of three rods can produce an arbitrary magnetic dipole moment vector which interacts with the earth’s magnetic field and produces a torque. This is a critical function in maintaining the desired spacecraft orientation and it can also be used to sense orbital location. However, for accurate attitude control and stabilization the torques provided often aren’t enough, making the existing torque rod technology suffer from low accuracy. Another disadvantage is the dependence on Earth’s magnetic field strength, making existing torque rod technology unsuitable for deep space missions. As a result, research on torque rods for spacecraft attitude control that helps overcome these difficulties can impact the total smallsats and cubesats market which is estimated to be $1.3B in size of revenues.

Consistent Spacecraft Attitude Control using Torque Rods with Low Residual Field and High Linearity

Researchers at Space Physics Research Lab at the University of Michigan have proposed a highly consistent torque rod technology for spacecraft attitude control. Rods that are designed by the proposed technology have very low residual magnetic dipole moments, are highly linear over the operating range, and have been severely tested over a wide temperature range. The materials used as well as the produced assembly and test procedures have resulted in high consistency of the rods. Additionally, the rods have been tested for thermal behavior in a vacuum environment and vibrated to meet launch specifications. The proposed technology has been applied to the design and construction of 24 flight-qualified rods for the Cyclone Global Navigation Satellite System (CYGNSS) constellation of spacecraft.

Applications

  • Spacecraft attitude control
  • Small satellites (i.e. smallsats and cubesats)

Advantages

  • Can be applied to new sets of requirements for small satellites
  • Low residual field
  • High linearity
  • Operational in a wide temperature range