ADAPT is a computer program that searches for better mathematical models for spacecraft navigation. The task of tuning trajectory-determination models for interplanetary navigation is complex, requiring an intensive search of multiple dynamical and nondynamical models that yield trajectory solutions with minimal errors. By automating the search, ADAPT eases the task of human analysts and enables them to consider wider ranges of potential solutions. ADAPT uses genetic algorithms to search a range of relevant parameters in a userselected design space to arrive at values for those parameters that best fit the measured spacecraft-tracking data. The user's guide for ADAPT reviews the theoretical basis of the program and presents two example applications. One example is that of selecting a solar-radiation model for the Mars Pathfinder (MPF) mission using MPF tracking data and an extended Kalman filter from prior spacecraft-navigation software. The second example is of the use of tracking data from the Stardust spacecraft mission combined with a pseudo-epoch-state batch filter and an empirical small-forces model to find improved impulse models for use during Stardust attitude adjustments.
This program was written by Todd Ely of Caltech and William Crossley of Purdue University for NASA's Jet Propulsion Laboratory.
This software is available for commercial licensing. Please contact Don Hart of the California Institute of Technology at (818) 393- 3425. Refer to NPO-30552.
This Brief includes a Technical Support Package (TSP).
Software Searches for Better Spacecraft-Navigation Models
(reference NPO-30552) is currently available for download from the TSP library.
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Overview
The document discusses ADAPT, a software tool developed by NASA’s Jet Propulsion Laboratory (JPL) designed to enhance spacecraft navigation through improved mathematical modeling. ADAPT automates the complex task of tuning trajectory-determination models for interplanetary navigation, which traditionally requires extensive manual effort and expertise. The software employs genetic algorithms to search a user-defined design space for optimal parameters that best fit measured spacecraft tracking data.
The need for such a tool arises from the increasing complexity of navigation tasks associated with multiple spacecraft missions, each presenting unique modeling challenges. Analysts often rely on generic models that may not accurately represent the specific conditions of a mission. For instance, during the Mars Pathfinder mission, the available models for solar radiation pressure were limited to flat plates and cylinders, which did not adequately account for the unique conical shape of the spacecraft's backshell. This limitation forced analysts to make approximations, complicating the navigation process.
ADAPT addresses these challenges by allowing users to select relevant parameters and facilitating a more efficient search for better navigation models. The software's ability to automate model optimization not only streamlines the analysis process but also enables analysts to consider a broader range of potential solutions, ultimately leading to more accurate trajectory predictions.
The document also highlights two specific applications of ADAPT: one involving the selection of a solar-radiation model for the Mars Pathfinder mission and another focusing on the Stardust spacecraft mission, where tracking data was used to improve impulse models for attitude adjustments. These examples illustrate the practical benefits of using ADAPT in real-world scenarios.
ADAPT was developed by Todd Ely of Caltech and William Crossley of Purdue University and is available for commercial licensing. The document emphasizes that the work was conducted under NASA's sponsorship and clarifies that references to specific products or services do not imply government endorsement.
In summary, ADAPT represents a significant advancement in spacecraft navigation technology, leveraging genetic algorithms to optimize models and improve the accuracy of interplanetary missions, thereby enhancing the capabilities of navigation analysts in the field.
