Knowing whether there are high explosives inside suspicious objects has many obvious benefits to the military and emergency teams that have to move them. A team of students in Florida has devised an unusual technique for remotely checking objects: shooting them with special bullets.
The project originated when Lockheed Martin asked graduate students at the University of Florida in Gainesville to come up with a technique that could determine whether packages or vehicles were filled with explosives. Motivation for the project came from the ongoing bombings in Iraq, particularly the many deadly and destructive car bombs.
A multidisciplinary team working during the 2003–2004 school year devised a way to encase a sensing system inside a projectile that can be fired by a paint gun. The team, working with a US$1,000 budget, used an inexpensive accelerometer instead of a TNT (trinitrotoluol) sensor.
The TNT sensor is the ultimate goal because it will sniff out different types of explosives. An inexpensive accelerometer was picked mainly for proof of concept, although measuring the shock when the projectile hits a potentially explosive target is not without benefit.
"TNT sensors took the project beyond the student's budget, so we used an accelerometer to measure the acceleration and the disturbance when it hit its target," says Loc Vu-Quoc, the mechanical engineering professor heading the program. However, Vu-Quoc says a chemical sensor could easily replace the accelerometer.
The team consisted of two mechanical and aerospace engineers and one each from the electronics, material science, industrial systems, and civil engineering departments. They devised a projectile that can travel up to 65 feet. "The projectile could be made lighter so it would fly farther," Vu-Quoc says.
The team covered the projectile with a sticky industrial polymer so that it will stick to an object, giving the sensors time to make their measurements—whether they're checking for explosives, anthrax, or other hazardous substances.
The projectile body and sticky material were critical design aspects; the electronics were another key component. "We also designed the printed circuit board, which holds a sensor, transmitter, battery, and antenna," Vu-Quoc says. The 450-MHz wireless transmitter the students used had a range of 240 feet, so an operator with a laptop computer could sit far from the object while analyzing the sensor data.
Once the students finished their proof-of-concept program, product development teams at Lockheed Martin began working to industrialize the firing mechanism and the intelligent projectile. Managers have put it on a fast track so that it can help save lives.
"I sure hope it will be ready soon. If we made it up with the right chemical sensors, it could have an immediate impact in Iraq," says Leslie Kramer, director and engineering fellow for missiles and fire control at Lockheed Martin.
Kramer feels that the students made great progress after receiving only loose ideas and guidelines last fall. "What the students did was spectacular. Now, we're looking at equipping [the projectile] with sensors that have the potential for explosive detection, and a number of other sensors as well," Kramer says.