Look-ahead flight path control for solar sail spacecraft

Abstract

Recent investigations of trajectory options that incorporate solar sails have been motivated by missions to observe planetary poles or to communicate with an outpost at the lunar south pole. Designing reference trajectories and understanding their fundamental dynamics are the necessary first steps toward flying spacecraft in dynamically complicated regimes. However, the existence of a reference orbit alone is insufficient for flight operations. Two variations of a turn-and-hold strategy are examined for flight-path control: an approach that implements multiple turns to achieve a target in an error-free scenario and an approach that incorporates a look-ahead strategy to accommodate representative errors.

Attitude dynamics in the circular restricted three-body problem

“…A popular strategy that employs a finite set of control variables, is termed the Turn and Hold (TnH) model. Within a TnH guidance law, a spacecraft is assumed to maintain a fixed orientation along each control arc, with respect to a relative or inertial reference [69]. Numerous analyses have already demonstrated that a sailcraft trajectory may be effectively controlled by reorienting a sail structure.…”

“…Along with new forms of motion, a solar sail offers the possibility to maintain a spacecraft in the vicinity of an equilibrium point or more generically, a reference orbit, by controlling the attitude configuration and, therefore, without the direct utilization of chemical propulsion. Several wellknown approaches such as, linearized optimal control [65,66], Hamiltonian structure-preserving stabilization [67], or look-ahead strategies [68,69] are generally applicable to the stationkeeping problem for a solar sail. The control input is typically determined by the orientation of a solar sail, which is defined in terms of some angles, or as a pointing vector.…”

An Adaptive, Receding-Horizon Guidance Strategy for Solar Sail Trajectories

“…Both of the sample orbits used in Wawrzyniak and Howell [8] are employed successfully as initial guesses in the generation of new trajectories based on an ephemeris model. Solutions in that study are based on motion modeled in the Earth-Moon CR3B system, where SRP is modeled but solar gravity is not.…”

“…Thereafter, the turn sequence is updated based on new state information. A primary conclusion from Wawrzyniak and Howell [8] is that the success of the "turn-and-hold" strategy depends on the duration of the subarcs and the number of subarcs used to design a turn sequence, as well as the actuation errors in the reorientation process.…”

“…In existing work by Wawrzyniak and Howell [8], a look-ahead, or recedinghorizon, strategy based on regular, discrete turn events is proposed (as opposed to continuously re-orienting the vehicle). A fixed number of days between reorientation events and a fixed number of turns are used in generating an attitude profile along an arc along the reference trajectory.…”