A critical adjustment to a laser ignition system at the heart of a cannon being developed for the US Army was devised by what Sandia National Laboratories calls its "light wizards." The non-line-of-sight (NLOS) cannon is part of Future Combat Systems (FCS), the Army's modernization program. Sandia is a key player in the program to design and manufacture the lightweight, high-caliber, self-propelled cannon system. The NLOS cannon is fully automated and can fire at a sustained rate of six rounds per minute. The vehicle, once completed, must be light and agile enough to fit three vehicles comfortably onto a C-17 cargo aircraft. The system is being developed by BAE Systems as part of The Boeing Co./SAIC led FCS Program. Sandia 'light wizard' Nipun Bhutani examines the NLOS cannon's laser ignition unit. Sandia researchers are developing an isolation system for the NLOS cannon that acts much like a filter, resulting in much lower shock levels. (Photo: Randy Wong) The laser ignition system was developed by the Armament Research, Development and Engineering Center (ARDEC) -- the Army's principal developer of armament and munitions sytems, in Picatinny, N.J. -- in collaboration with Kigre Inc., a Hilton Head., S.C., maker of solid-state laser components. The unit is mounted on the back of the cannon's gun barrel, where a laser beam is fired through an opening mechanism (the breech) to ignite the charge and launch an artillery shell. However, said Nipun Bhutani, project manager for the lab's work on the NLOS cannon, the recoil force and shock of the projectile (bullet) discharge had caused an increase in observed failures during early prototype testing. "The laser ignition system offers much better precision, rapid fire and automation than the mechanical method, and it's safer," says Bhutani. "But it's obviously not going to be an effective long-term solution if reliability cannot be maintained." Instead of abandoning the laser ignition concept in favor of traditional, mechanical ignition, the Army called in experts at Sandia, who deal with shock issues for a variety of components. To absorb the force from the discharge, Sandia and ARDEC jointly proposed a new isolation system between the laser and the breech. Vibration isolation systems are widely used to protect sensitive devices from vibrations or shock produced in their environment. Typical examples include isolating delicate laboratory experiments from floor-borne vibrations, or isolating a car body or airplane frame from engine vibrations. Sandia, in collaboration with BAE Systems and ARDEC, is developing an isolation system for the NLOS Cannon that acts much like a filter and results in much lower shock levels. In addition to the isolation system, Sandia's researchers incorporated the lab's modeling and experimental capabilities that are leading to hardening of the laser igniter. The NLOS cannon, developed by BAE Systems, is fully automated and can fire at a sustained rate of six rounds per minute. (Photo courtesy BAE Systems) In an effort to develop the most optimal isolation system possible, Bhutani said, the Sandia team needed to model the physics and inner workings of the laser system components. This involved modeling the gun loads and other physical dynamics inside the laser ignition system, particularly as it is fired. Bhutani said, "In keeping with Sandia tradition, we developed an entire systems approach to the problem," which included not only analysis and modeling of the isolation system but building a prototype and further researching the system's performance and reliability. Sandia also did modeling work on the laser and breech. The lab also supports BAE Systems' test efforts. One of Sandia's long-term objectives with its NLOS cannon work, said Bhutani, is to hone its customer relations reputation and strengthen alliances with BAE Systems; Armament Research, Development and Engineering Center (ARDEC); Benet Laboratories; and others. "We want to be known among our current and future customers as the 'go-to' lab," says Bhutani. Sandia is a National Nuclear Security Administration laboratory. For more information, visit: www.sandia.gov