Applications of Multi-Body Dynamical Environments: The ARTEMIS Transfer Trajectory Design

The application of forces in multi-body dynamical environments to pennit the transfer of spacecraft from Earth orbit to Sun-Earth weak stability regions and then return to the Earth-Moon libration (L1 and L2) orbits has been successfully accomplished for the first time. This demonstrated transfer is a positive step in the realization of a design process that can be used to transfer spacecraft with minimal Delta-V expenditures. Initialized using gravity assists to overcome fuel constraints; the ARTEMIS trajectory design has successfully placed two spacecraft into EarthMoon libration orbits by means of these applications

Interactive Spacecraft Trajectory Design Strategies Featuring Poincaré Map Topology

Space exploration efforts are shifting towards inexpensive and more agile vehicles. Versatility regarding spacecraft trajectories refers to the agility to correct deviations from an intended path or even the ability to adapt the future path to a new destination—all with limited spaceflight resources (i.e., small ΔV budgets). Trajectory design methods for such nimble vehicles incorporate equally versatile procedures that allow for rapid and interactive decision making while attempting to reduce Δ V budgets, leading to a versatile trajectory design platform. A versatile design paradigm requires the exploitation of Poincaré map topology , or the interconnected web of dynamical structures, existing within the chaotic dynamics of multi-body gravitational models to outline low-Δ V transfer options residing nearby to a current path. This investigation details an autonomous procedure to extract the periodic orbits (topology nodes) and correlated asymptotic flow structures (or the invariant manifolds representing topology links). The autonomous process summarized in this investigation (termed PMATE) overcomes discontinuities on the Poincaré section that arise in the applied multi-body model (the planar circular restricted three-body problem) and detects a wide variety of novel periodic orbits. New interactive capabilities deliver a visual analytics foundation for versatile spaceflight design, especially for initial guess generation and manipulation. Such interactive strategies include the selection of states and arcs from Poincaré section visualizations and the capabilities to draw and drag trajectories to remove dependency on initial state input. Furthermore, immersive selection is expanded to cull invariant manifold structures, yielding low-ΔV or even ΔV-free transfers between periodic orbits. The application of interactive design strategies featuring a dense extraction of Poincaré map topology is demonstrated for agile spaceflight with a simple spacecraft rerouting scenario incorporating a very limited Δ V budget. In the Earth-Moon system, a low-ΔV transfer from low Earth orbit (LEO) to the distant retrograde orbit (DRO) vicinity is derived with interactive topology-based design tactics. Finally, Poincaré map topology is exploited in the Saturn-Enceladus system to explore a possible ballistic capture scenario around Enceladus

An application of visual analytics to spacecraft trajectory design

Recent developments in astrodynamics suggest a wealth of design potential within the context of the circular restricted three-body problem. Exploitation of the expanding dynamical and mathematical insights, though, has been difficult to capture in a real-time design setting. Emerging from the ability to represent large amounts of information through visual environments, visual analytics is a new science that focuses on the application of graphical depictions to facilitate discovery. Moreover, visual analytics blends the science of analytical reasoning with the implementation of interactive visual interfaces. This investigation blends the fundamental elements of trajectory design in multi-body regimes with the implementation of visual analytics, thereby merging visualization tools, differential corrections algorithms, and the intuition of a knowledgeable designer into one expansive design approach. The application of visual analytics to spacecraft trajectory design then supplies a tool for rapid investigation and design with access to a wider range of options for the construction of trajectories that meet mission requirements. A process for the visual construction of initial guesses that seed targeting algorithms is developed in conjunction with the instant application of a corrections module that offers various options. An interactive definition of Poincaré sections in various subspaces is accomplished with visual transformation tools; implementation of a graphics processing unit (GPU) for computation expedites the generation of Poincaré maps. End-to-end spacecraft trajectories are designed that exploit the asymptotic flow and chaotic behavior in the circular restricted three-body problem with the application of visual analytics