Advanced Imaging


Advanced Imaging Magazine

Updated: January 12th, 2011 09:49 AM CDT

Providing 3D Analysis of Space Shuttle Heat Shield Tiles

A processed image of a tile
A processed image of a tile showing selected repair material and cracks. Astronauts made the repairs in space. (Images courtesy Smart Imaging Technologies)
An original 3D image of a tile with a cut plane.
An original 3D image of a tile with a cut plane.
3D analysis
3D analysis can be instantly previewed for adjustments. Results may be imaging, numerical or graphical.

Smart Imaging Technologies (Houston, Texas)

The Imaging Challenge

As a part of the Space Shuttle Safety Program, NASA needed to analyze the quality and usability of new NOAX material developed to repair damaged RCC Heat Shield Tiles. Repairs were performed in space by the astronauts during a space walk. To compare quality of repairs for different grades of material, NASA needed to objectively and quantitatively evaluate cracks and pores in the internal structure of the tiles repaired in space during the space mission.

The Solution

3D images of the internal structure of RCC Heat Shield tiles are obtained from a CT scanner, but the human eye is not capable of objectively and quantitatively comparing samples that have close characteristics. Another problem is that measuring porosity and cracks on 2D slices of the image is not representative of the actual 3D system because pores and cracks may interconnect through the third dimension (tortuosity). To solve this problem, Smart Imaging Technologies developed a specialized automated 3D image metrology solution using SIMAGISŪ software platform that automatically performs the following functions:

  • Registers and classifies target phases in 3D CT images: tile volume; repair layer; cracks and pores
  • Provides automated quantitative 3D characterization of layers cracks and pores including;
    • Number of pores (cracks);
    • Volume of layer and pores;
    • Surface area of the pores and layer;
    • Pore specific area (pore surface area to volume ratio);
    • Layer specific area (layer surface area to volume ratio);
    • Layer porosity (volume of the pores to layer volume ratio);
    • Pore diameter distribution (width map);
    • Data on isolated and percolated pores, i.e. top contacting pores (very important for shuttle safety); and
    • Share of isolated and percolated pores with regard to the layer
  • Provides nine different characterization reports and graphs for characterization of quality of the repairs

The Tools Used

  • FlashCT, Volume CT Scanner by Hytec Inc., Los Alamos, New Mexico
  • SIMAGISŪ 3D, software platform for image analysis automation by Smart Imaging Technologies

The Difference it Made

Using this imaging solution, NASA could objectively compare repairs done in space using different grades and formulas of NOAX material and guide the development process for repair procedures and patch material for space shuttle heat shield tiles.

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