To date, bond strength is considered one of the ?holy grails? for NDE. Preliminary data indicates that the Luna Nonlinear Ultrasonic Bond Strength (NUBS) monitor will permit a nondestructive evaluation of bond strength for many classes of adhesives and bond configurations. The technology is based on high-resolution ultrasonic measurements that extract nonlinear parameters of the elastic bond properties. Working with Professor David Dillard, a recognized international expert in adhesion science at Virginia Tech., the Luna team will validate the NUBS concept using butt-joints and shear-lap joints with a family of adhesives and surface preparations. The tests will help Luna optimize the device electronic design while determining the range of use for quantitative assessments. The result of this R&D if carried to the Phase II will be a cost-effective field instrument that has wide applicability for one-sided bond assessment testing. This is especially critical for NASA as aerospace structures rely more and more on adhesives for beneficial design characteristics.