Zoom out to the physics, because this is gyroscopes all the way down. A spinning mass resists changes to its axis, and exchanging momentum between a spinning mass and the spacecraft body lets you rotate the body in a controlled way without expending propellant. Reaction wheels and control-moment gyroscopes are the familiar incarnations; this grant works the same vein.
The grant US11174046B2 (inventor Larry D. Sinclair), classified in B64G 1/28 and B64G 1/283 (attitude control by rotating masses) with B64G 1/425 and B64G 1/443, claims a rotating-mass attitude-control system. The clustering of momentum-control CPC codes is the signature of a pure attitude-control invention.
Here is why the old idea keeps getting re-patented. Momentum-based control is propellant-free, and propellant is the scarcest resource on most satellites; every kilogram of fuel you do not spend pointing is mass you can spend on mission or on lifetime. The engineering competition is in how compactly and reliably you can store and manage the momentum.
It rhymes with the broader 2021 attitude-control wave, from magnetic residual-dipole methods to single-axis magnetic pointing, all chasing the same goal: more pointing authority, less mass, fewer consumables. Different mechanisms, one destination, a satellite that holds its attitude cheaply and for a long time.
The accessible caveat: rotating-mass systems can saturate. Spin a wheel up to absorb a persistent disturbance and eventually it hits its limit and needs to be desaturated, usually with thrusters or magnetic torquers. The patent describes a clever momentum-management scheme; the system around it still has to deal with where all that stored momentum eventually goes.