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Formation Modeling

Task Objective

Our research advances the state of the art in modeling and simulation capabilities to enable high-fidelity, real-time simulation of high-precision spacecraft formations and clusters through the application of parallel and distributed technologies.

Task Products

Modeling and Simulation Algorithms

Terrestrial Planet Finder
Terrestrial Planet Finder (artist's rendition)
One of the fundamental issues in the simulation of spacecraft formations and clusters is that the universe is inherently parallel: the states and trajectories of objects in space evolve simultaneously. An example of this is light passing through the telescopes of two spacecraft and then reflected to a third spacecraft combining those two sources. Each of the spacecraft executes maneuvers and controls the light at the same time as the others. Traditional simulation approaches must compute these effects in order (or serially) for each spacecraft, so it takes longer to perform the simulation as more spacecraft are added. This severely restricts the accuracy of the simulation and the complexity of the models it uses, especially when the simulation is used in real time to test flight hardware and software.

A better approach is to take advantage of the distributed nature of the formation and distribute the simulation among multiple processors in a simulation cluster. This powerful method can produce simulations that operate in constant time versus the number of spacecraft, but comes at a cost. We are developing new models and simulation paradigms in order to permit parallel and distributed simulation of formations.

In addition, traditional simulation techniques are not accurate enough for this class of missions. Distances in formation missions can be measured and controlled at the level of nanometers, while the formation size can range from meters to kilometers. Current real-time simulation technologies for spacecraft missions typically maintain relative accuracies on the order of 109, while formation missions require much higher precision on the order of 1011 or better. Incorporation of modern integration techniques into the distributed environment will provide the necessary increase in accuracy.

Simulation Architecture

Hydra Architecture chart
We are building a new simulation architecture, loosely modeled on the HLA, that enables the application and use of the technologies developed in our research. The Hierarchical Distributed Reconfigurable Architecture (HYDRA) is designed for seamless deployment of simulation components and technologies across a wide array of architectures, from single-CPU to distributed, mixed- and multi-platform environments. HYDRA automates the process of connecting and communicating between simulation components, while allowing these automated behaviors to be overridden as necessary.


One key element of our research is infusion of new technologies into other active research and flight development programs. HYDRA and the developed technologies have been successfully infused into the Formation Algorithms and Simulation Testbed (FAST) as part of the TPF technology program. HYDRA is also in consideration for the Space Interferometery Mission (SIM) (SIM) testbeds.


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