This article studies the appointed-time attitude tracking control of spacecraft on special orthogonal group, with forbidden zone, parameter uncertainties, and external disturbances. A novel projection function is proposed, such that normalized boresight vector sensitive instrument mapped to a reduced dimensional in Euclidean space. If uniformly bounded, constraint zone will be satisfied at all ...

Small satellites are now capable of performing missions that require accurate attitude determination and control. However, low size, power, and cost requirements limit the types of attitude sensors that can be used on a small craft, making attitude estimation difficult. In particular, star trackers—often the attitude sensors of choice for larger spacecraft—are not practical for small satellites...

These days, nano (1 kg – 10 kg ) and micro (10 kg – 100 kg) – satellites, which are smaller than conventional large satellite, provide space access to broader range of satellite developers and attract interests as an application of the space developments because of shorter development period at smaller cost. Several new nanoand micro-satellite missions are proposed with sophisticated objectives...

We sought increased understanding of men’s decision-making process for prostate-specific antigen (PSA) screening, especially among elderly men, and a more knowledgeable basis for interventions to modify screening rates. A cross-sectional postal questionnaire assessed measures consistent with the Theory of Planned Behavior among a population-based age-stratified random sample of 452 Iowa men who...

In the paper, the predictive control method is proposed to control the synchronization of two perturbed satellites attitude motion. Based on delayed feedback control of continuous-time systems combines with the prediction-based method of discrete-time systems, this approach only needs a single controller to realize synchronization, which has considerable significance in reducing the cost and co...

in this paper, a finite-time control scheme is presented for stabilization ofthe satellite chaotic attitude around its equilibrium point whenits attitude is confused by a disturbed torque. controllers and settling timeof stabilizaton are obtained, based on the lyapunov stability theoremand finite-time control scheme. this method is satisfied for any initial condition.numerical simulations are ...