In this paper the earth’s magnetic field is simulated precisely while the intensity and direction of the field are verified with one of the standard references for selected points on the earth and the results are compared with some low-order models. In another simulation, the complete model is compared with a common approximate model. The magnetic field in orbital frame is described and to empl...

the problem of relative motion control for spacecraft formation flying in eccentric orbits is considered in this paper. due to the presence of nonlinear dynamics and external disturbances, a robust fuzzy sliding mode controller is developed. the slopes of sliding surfaces of the conventional sliding mode controller are tuned according to error states using a fuzzy logic and reach the pre-define...

In this article, the issue of attitude control and active vibration suppression of a nonlinear flexible spacecraft is assessed through piezoelectric patches as actuator and sensors. Two controller loops are applied: the inner loop, to make the panel vibration damped through piezoelectric patches; and the outer loop, to perform spacecraft maneuver using the reaction wheel acting on the hub. An o...

Air-bearing-based spacecraft simulators are widely used to develop and verify spacecraft control techniques required by modern spacecraft applications. To create a spacelike environment with ground spacecraft simulators, the effects of gravity should be minimized. For a spherical air-bearing system with 3 rotational degrees of freedom, the center of rotation of the spacecraft simulator should b...

1. ABSTRACT As a result of the interaction between the spacecraft and its operational environment, the constituent materials begin to change. These changes are determined by a combination of energy deposition, the resulting chemical reactions, and contamination. These changes negatively impact the ability of spacecraft operators to predict the behavior of a spacecraft as it ages. For example, i...

-The attitude stabilization problem of a rigid spacecraft using control torques supplied by gas jet actuators about only two of its principal axes is considered. If the uncontrolled principal axis of the spacecraft is not an axis of symmetry, then the complete spacecraft dynamics are small time locally controllable. However, the spacecraft cannot be asymptotically stabilized to any equilibrium ...

In this paper the attitude tracking problem is solved for a flexible spacecraft in the case of measurements of the variables describing the attitude error. Such a control could be applied in failure situations for recovering a spacecraft, so increasing the fault tolerance of the spacecraft control system and the success of the mission. The result is a dynamic controller capable of reconstructin...

Electrostatic charging of a spacecraft modifies the distribution of electrons and ions before the particles enter the sensors mounted on the spacecraft body. The floating potential of magnetospheric satellites in sunlight very often reaches several tens of volts, making measurements of the cold (several eV) component of the ambient ions impossible. The plasma electron data become contaminated b...

A batch filter has been designed and analyzed to autonomously determine the orbits of 2 spacecraft based on measurements of the relative position vector from one spacecraft to the other. This system provides a means for high-precision autonomous orbit determination for systems that cannot be dependent on signals from the GPS constellation or ground stations. The filter uses a time series of the...