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...

The topic of autonomous close-range rendezvous is discussed in this paper. When designing a controller for an autonomous system, it is important to model the environment of the system as precisely as possible. This paper discusses the disturbances encountered in space and their effects on the rendezvous controller with particular focus on the effects in fuel usage and mission times. Simulations...

Radial velocity surveys are beginning to reach the time baselines required to detect Jupiter analogs, as well as sub-Saturn mass planets in close orbits. Therefore it is important to understand the sensitivity of these surveys at long periods and low amplitudes. In this paper, I derive analytic expressions for the detectability of planets at both short and long periods, for circular and eccentr...

We have performed a detailed analysis of orbital motion in the vicinity of a nearly extremal Kerr black hole. For very rapidly rotating black holes—spin parameter a J=M > 0:9524M—we have found a class of very strong-field eccentric orbits whose orbital angular momentum Lz increases with the orbit’s inclination with respect to the equatorial plane, while keeping latus rectum and eccentricity fix...

Orbits of known extrasolar planets that are located outside the tidal circular-ization regions of their parent stars are often substantially eccentric. By contrast, planetary orbits in our Solar System are approximately circular, reflecting planet formation within a nearly axisymmetric, circumsolar disk. We propose that the remarkable elongations of extrasolar planetary orbits are a consequence...

We consider the effect of gravitational perturbations from a nearby satellite on the eccentricity e of a narrow particulate ring. The perturbations near a resonance in an eccentric ring may be divided into corotation and Lindblad terms. For small e, the corotation terms da,np e, whereas the Lindblad terms excite e. In the absence of saturation the corotation terms win by. a small margin, and e ...

Orbits of known extrasolar planets that are located outside the tidal circular-ization regions of their parent stars are often substantially eccentric. By contrast, planetary orbits in our Solar System are approximately circular, reflecting planet formation within a nearly axisymmetric, circumsolar disk. We propose that or-bital eccentricities may be generated by divergent orbital migration of ...

The recent discovery of a planet in an orbit with eccentricity e = 0.63± 0.08 around the Solar-type star 16 Cyg B, together with earlier discoveries of other planets in orbits of significant eccentricity, raises the question of the origin of these orbits, so unlike the nearly circular orbits of our Solar system. In this paper I consider close encounters between two planets, each initially in a ...