NDE studies have shown that Laser based Interferometric techniques such as Holographic Interferometry (HI), Electronic Speckle Pattern Interferometry (ESPI) and Electronic Speckle Shearographic Interferometry (ESSI) techniques are useful for NDE of honeycomb sandwich panels and propellant tanks by applying stressing techniques like thermal, vibration, pressure, vacuum, etc.

Instrumented Coin Tap (ICT) was found to be suitable for debond detection in honeycomb panels made of both metal and composite facesheets. Acoustic Emission (AE) is found useful for predicting the failure load of inserts in honeycomb panels during proof load tests. Also, experimental modal test techniques are used to check the integrity of the satellite structural components and assemblies. Thermography is widely used for NDE of structural components made of composite materials. With the above applications in mind, a Virtual Instrument (VI) is configured and realised using a high speed data acquisition and an image grabbing PC plug-in cards with associated signal and image processing software respectively. Visual Programming software systems are used which greatly simplified the coding efforts and are an integral part of the VI system. A number of innovations done in the application of these techniques for NDE of sandwich construction are also incorporated in this system which makes it more effective. Necessary state of the art software and hardware elements are integrated and installed for use in a production environment which can be used even by a la user. Recent trends in the development of low cost thermovision systems using Focal Plane Array (FPA) sensors can easily be integrated later with limited efforts.

This paper is a summary of the developments described above resulting in significant improvements in the application of NDE techniques for spacecraft. Details of computer hardware and software implementation and a few typical application examples are also included in this paper.