Pulsed thermographic evaluation of disbonds in the insulation of solid rocket motors made of elastomers

Solid rocket motors (SRMs) are key components of missiles, space rockets and shuttles. In order to prevent their combustion chamber cases from being damaged by high-temperature and high-pressure gas, they must be protected by special thermal insulation layers. Disbonds, or poor bonding in the adhesion interfaces often appear during manufacture because of technological reasons, thus possibly causing catastrophic failure of space vehicles when in operation. Pulsed IR thermography (PIRT) has been used successfully for detecting defects in aero space components due to its high productivity, one-sided access and safe exploitation. This paper describes some results of applying PIRT to the inspection of the thermal insulation of SRM cases. Particular emphasis is laid on the development of some novel approaches based on the correlation technique.