ENGINEERING NOTES are short manuscripts describing new developments or important results of a preliminary nature. These Notes cannot exceed 6 manuscript pages and 3 figures; a page of text may be substituted for a figure and vice versa. After informal review by the editors, they may be published within a few months of the date of receipt. Style requirements are the same as for regular contribut...

This paper deals with the attitude motion of a dual-spin spacecraft which consists of an asymmetric rigid platform and an asymmetric rigid rotor connected together by a flexible joint. The equations of motion represent a flexible multiple-degree-of-freedom gyroscopic system with periodic coefficients due to asymmetries. The equations are analyzed for possible resonances and associated instabili...

A closed loop switching function for single-axis slew maneuvers of spacecraft using on-off thrusters is investigated by analytical simulations and experimental demonstrations. The proposed switching function provides flexibility of controlling multiple firing and pointing errors in the presence of modelling errors and structural flexibility. The proposed switching functions for three-axis maneu...

Complex interplanetary spacecraft and newly proposed satellites for reconnaissance and strategic defense are being designed with increasingly light and flexible appendages despite ever more demanding requirements for accurate pointing and tracking. The onboard control systems required to satisfy these strict requirements during reasonably quiescent conditions must also act effectively to limit ...

This paper proposes a novel neural adaptive fixed-time control approach for the attitude stabilization and vibration suppression of flexible spacecraft. First, network (NN) was introduced to identify lumped unknown term involving uncertain inertia, external disturbance, torque saturation, elastic vibrations. Then, proposed controller synthesized by embedding NN compensation into backstepping fr...