1. The information and data reported in this Allied Ordnance Publication (AOP) was derived from a NATO Research and Technology (RTO)@ Advanced Vehicle Technology (AVT)@ Task Group (TG) 016 that was active from October 1997 to August 2001. A complete report of results from this Task Group??s efforts is presented in Reference [A]. 2. The focus of this AOP is non-intrusive instrumentation used at the laboratory scale to determine the burning rate characteristics of a solid propellant. Some of those methods might be further used and standardized for solid rocket motor applications: A survey is presented for different non-intrusive tests used by various laboratories during the time the TG was active. 3. The AOP does not present any specific standardized instrument to measure solid rocket propellant burning rate. It does@ however@ give a recommendation for the use of ultrasonic instrumentation for motor applications. 4. The design of small motor tests for measuring the burning rate of solid rocket propellants is the subject of AOP-57@ ??Tests for Measuring the Burning Rate of Solid Rocket Propellants?? [B]. 5. Analysis of data from the small motor test to determine burning rate is the subject of AOP-58@ ??Methods for Analyzing Data from Tests Designed to Measure the Burning Rate of Solid Rocket Propellants?? [C]. 6. Many advanced methods for measuring burning rate do not perturb the combustion process. These are broadly called non-intrusive techniques. These techniques use ultrasonic waves@ x-ray radiation@ microwaves@ and changes in material properties with thickness to determine the propellant burning rate. While many of these techniques have been developed to measure transient combustion [1]@ the methods are readily applied to steady-state measurements. All the non-intrusive techniques reviewed have been demonstrated on propellants in combustion bombs. Some have been demonstrated on motor applications. 7. The objectives for this AOP are; to review the most promising non-intrusive methods currently at operational status or in development (combustion bombs??); to analyze the limitations of the non-intrusive methods considered and define the improvements. Other summary papers have been written based partly on the material collected for this AOP [2@3@4]. 8. The AOP is organized into sections by the non-intrusive technique being discussed. Table 1 summarizes the diagnostic techniques reviewed in this AOP. The table indexes the section that covers each topic and briefly describes the physical basis of the measurement. An interesting initial observation is that the location of the burning surface (or distance) is the parameter that is sensed. Time derivatives of successive measurements are required to deduce the burning rate. The time derivative of measured parameters generally amplifies the measurement uncertainty. 9. Each section of this AOP explains the physical basis for the measurement; summarizes typical applications@ and assesses the potential for propellant screening@ development@ and qualification. The applications for each technique are ordered according to the nation reporting the application. The most promising techniques for routine propellant evaluation are recommended in the final section