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Chang'E-2(CE-2) extended mission started from June 2011, the maximum distance between CE-2 and the Earth is about 1,700,000 km. In this paper, orbit determination for CE-2 extended mission is discussed, and the orbit accuracy during transfer orbit phase is assessed. The results show that under current tracking condition, the orbit accuracy during the early escape orbit phase is at the level of 1km...
A nonlinear optimal control strategy is formulated to design optimal continuous low-thrust transfers between three dimensional Halo orbits in the vicinity of the second libration point of the Sun-Earth system. The nonlinear optimal control method based on the circular restricted three-body problem model, which uses the dual variable principle, is transformed into nonlinear algebraic equations for...
Passive and periodic formations minimize the active control of long-term satellite formation flying. Among different passive and periodic formations, the circular-like ones have potential applications in many formation flying missions. This paper shows that such formations under J2 perturbation are only possible at the critical inclination. It is revealed that strict constraints for both the reference...
Cluster of formation flying satellites consists of several companion satellites that make relative motion to a central satellite. The trajectory of relative motion is ellipse with special properties. On secular flying of formation satellites, various perturbation factors may cause relative drifts to the satellites. J2 perturbation has a great effect on the satellites formation flying. The article...
Control of a satellite system with an electrodynamic tether as actuator is a time-periodic and underactuated control problem. This paper considers the tethered satellite in a Hamiltonian framework and determines a port-controlled Hamiltonian formulation that adequately describes the nonlinear dynamical system. Based on this model, a nonlinear controller id designed that will make the system asymptotically...
Formation keeping control design for formations in eccentric Earth orbits is considered. The overall control design follows a non-hierarchical control architecture based on virtual structure approach. For the local level control, the linear parameter varying model describing the relative motion of member satellites is approximated by an uncertain model with polytopic uncertainty and an infinite horizon...
This paper provides the dynamic model of the deployment of tether-assisted re-entry system include J2 perturbation based on Lagrange equation. Some qualitative analyses of J2 perturbation effect on the system are given based on the dynamic model: J2 perturbation effect will induce some offset according to the deployment track of the system. Then a mathematic simulation is provided to validate and...
This describes a NOAA-14 spacecraft loss of control event and the lessons learned. The lessons learned are in two categories: contingency recovery operations; and on-orbit propulsion system isolation methods. The work is motivated in recognition of the effort of the NOAA off-line engineering support team and their NOAA civil servant mission leads and operations support staff.
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