A software tool is used to demonstrate the feasibility of Touch and Go (TAG) sampling for Asteroid Sample Return missions. TAG is a concept whereby a spacecraft is in contact with the surface of a small body, such as a comet or asteroid, for a few seconds or less before ascending to a safe location away from the small body. Previous work at JPL developed the G-TAG simulation tool, which provides a software environment for fast, multi-body simulations of the TAG event. G-TAG is described in “Multibody Simulation Software Testbed for Small-Body Exploration and Sampling,” (NPO-47196) NASA Tech Briefs, Vol. 35, No. 11 (November 2011), p.54. This current innovation adapts this tool to a mission that intends to return a sample from the surface of an asteroid.
In order to demonstrate the feasibility of the TAG concept, the new software tool was used to generate extensive simulations that demonstrate the designed spacecraft meets key requirements. These requirements state that contact force and duration must be sufficient to ensure that enough material from the surface is collected in the brush-wheel sampler (BWS), and that the spacecraft must survive the contact and must be able to recover and ascend to a safe position, and maintain velocity and orientation after the contact.
This work was done by Lars James C. Blackmore, Behcet Acikmese, and Milan Mandic of Caltech for NASA’s Jet Propulsion Laboratory.
This software is available for commercial licensing. Please contact Daniel Broderick of the California Institute of Technology at
This Brief includes a Technical Support Package (TSP).
Adaption of G-TAG Software for Validating Touch and Go Asteroid Sample Return Design Methodology
(reference NPO-47193) is currently available for download from the TSP library.
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Overview
The document outlines the development and application of a new software tool at NASA's Jet Propulsion Laboratory (JPL) designed to validate the feasibility of Touch and Go (TAG) sampling for Asteroid Sample Return missions. TAG is a method where a spacecraft briefly contacts the surface of a small celestial body, such as an asteroid or comet, to collect samples before ascending to a safe distance.
The report emphasizes the importance of extensive simulations to ensure that the spacecraft meets key mission requirements, which include sufficient contact force and duration to collect material, the spacecraft's ability to survive the contact, and its capability to safely ascend after sampling. The G-TAG simulation environment is adapted for this purpose, allowing for the generation of time histories of critical parameters during the sampling event.
Key findings from the simulations indicate a high probability of mission success. Specifically, there is a 91% chance that a single sampling event will meet the mission success criteria, which includes the sample container being sufficiently filled. The likelihood of completely filling the sample container is estimated at 74%, while the chance of requiring a second sampling event is only 9%. Additionally, the risk of catastrophic failure during the sampling event is less than 1%, demonstrating the robustness of the spacecraft design against potential risks.
The document also includes references to various simulation scenarios, detailing the estimated probabilities of different outcomes based on specific operational parameters, such as sampling slope and velocities. These simulations are crucial for validating the design methodology and ensuring that the spacecraft can effectively execute the TAG concept.
In conclusion, the report highlights the innovative approach taken by JPL in developing the G-TAG software tool, which plays a vital role in the planning and execution of asteroid sample return missions. By providing a comprehensive assessment of the operational and environmental parameters, the tool enhances the understanding of the TAG process and contributes to the overall success of future space exploration endeavors.
