A computer program under continuing development strives to locate a safe landing site for a spacecraft through realtime processing of image data acquired by a video camera aimed at the terrain below while the spacecraft descends. The program might also be useful for aiding the selection of a landing site for an unpiloted helicopter or other unpiloted aircraft capable of slow vertical or nearly vertical descent. The program implements two main algorithms: a texture-based landing-site-selection algorithm and a landing-site slope-estimation algorithm. The texture-based algorithm analyzes spatial variations in image brightness to identify candidate sites that are acceptably smooth and free of large rocks. The slope-estimation algorithm computes the slope on the basis of the perspective relationships between two images of the same terrain area acquired from successive positions along the descent trajectory. Because the slope is a very important factor for safe landing and for mobility of a robotic exploratory ground vehicle to be deployed from the spacecraft after landing, the slope-estimation algorithm includes an error-analysis subalgorithm.

This program was written by Yang Cheng, Andrew Johnson, Larry Matthies, and Aron Wolf of Caltech for NASA’s Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Software category.

This software is available for commercial licensing. Please contact Don Hart of the California Institute of Technology at (818) 393- 3425. Refer to NPO-30268.


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NASA Tech Briefs Magazine

This article first appeared in the June, 2002 issue of NASA Tech Briefs Magazine.

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