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The article presents a paper which examined optimal spacecraft formation motion design for fuel-image optimality. According to the authors, they developed an optimal control problem that optimizes fuel expenditure while meeting imaging goals. It states that the study is important to current and future work related to motion path planning of deep-space, separated spacecraft interferometric missions used for the imaging of exosolar targets as those sought in the Origins Program of the U.S. National Aeronautics and Space Administration (NASA).

We address the question of design and optimal control of a class of dual-spacecraft interferometric imaging formations. The first main contribution is that we combine two ideas introduced separately in the literature and propose a maneuver that offers improved imaging performance. We then formulate an optimal control problem to minimize fuel consumption and maximize image quality by minimizing the relative speed, which is proportional to the signal-to-noise ratio (SNR) of the reconstructed image. We show that the necessary conditions are also sufficient and that the resulting optimal control is unique. Finally, we apply a continuation method to solve for the unique optimal trajectory. [ABSTRACT FROM AUTHOR]

This paper revisits a class of Earth-orbiting interferometric observatories introduced previously and reviews the general procedures to achieve wave-number plane coverage. The effect of eccentric spacecraft trajectories and gravity field J2 perturbations on wave-number plane coverage are considered. Conditions for complete wave-number plane coverage are found for certain classes of orbit perturbations. This analysis leads to design criteria for interferometric observatories that ensure wave-number plane coverage as a function of perturbation strength. [ABSTRACT FROM AUTHOR]

The concept of a spinning two-craft Coulomb tether is introduced. Here a physical tether is replaced with an electrostatic force field resulting in an attractive Coulomb force between the two craft. This results in conic section motions similar to the two-body gravitational problem, with spinning in-plane and out-of-plane motions. The spacecraft charge is assumed to be regulated with an active charge servo system. The stability of a Coulomb tether with constant spacecraft charges is investigated. The reduced equations of motion for a deep-space mission are obtained and linearized to determine eigenvalues of the perturbed motion. This analysis shows that if the plasma Debye length is smaller than the spacecraft separation distance, the radial motion is guaranteed to be unstable. For larger Debye lengths the nonlinear radial motion is locally stable. The perturbed out-of-plane motion is shown to always be stable regardless of Debye length. Further, open-loop charge solutions are obtained to perform reconfiguration where the circular orbit radius is changed to a new value. This maneuver is related to the classical Hohmann transfer orbit between circular orbits. However, in the Coulomb tether concept, the reconfiguration is achieved by varying the effective gravitational parameter through spacecraft charge changes. [ABSTRACT FROM PUBLISHER]