Professor Robert Pastore is a senior lecturer in the Department of Physics. He graduated from Stevens in 1986 with a bachelor’s degree in Engineering Physics. In the following years, he also completed both his masters and Ph.D. in Physics at Stevens. Initially torn between electrical engineering and engineering physics, he decided he preferred the physics route due to his interest in lasers and optics. “I thought that was neat,” said Pastore. When he was close to completing his undergraduate degree, he did an on-campus interview with the U.S. Army and was offered a job at the Fort Monmouth military base here in New Jersey, where he would work for the next 25 years.
He was employed in the Electronics Technology and Devices Laboratory. The main research done in this laboratory was to develop communications and the electronics needed to support any army mission. Pastore worked specifically in the Pulse Power Branch, where they did research with high voltage and high power systems, specifically high voltage switches and capacitors, handling anywhere from 50,000 to 100,000 Volts. They worked to test specific components and make sure that the capability of the materials was accurate and matched the army’s needs.
One project that Pastore worked on centered around the development of a new type of cannon, called an electrothermal-chemical gun. In this new type of gun, a specific combination of capacitors and inductors would create a type of speed ramp for the projectile. The propellant would be burnt in an increasing fashion, which would maintain the high pressure behind the projectile. This would increase the projectile’s acceleration as it moved down the barrel of the gun.
Working on such powerful systems included a certain amount of danger. The largest incident they ever caused was when they were testing a circuit of 50 large capacitors in parallel. Placing capacitors in parallel increases the overall amount of charge in the system. The circuit also contained five spark gap switches. Spark gap switches contain a gas that when exposed to a spark, start the flow of current. This system was connected to a load that simulated the cannon’s propellant.
They built the circuit using aluminum bars, which had become worn down from frequent usage. When they flipped the switches, the aluminum bars shattered and dumped 20,000 to 30,000 amps into the ground all at once. A current of 0.1 amps is capable of killing a person. This blew out the power in the entire section of the base and lit the substation on fire. The general’s office lost power and everyone had to be sent home for the day. “So that was fun,” Pastore remarked.
Eventually, the high voltage section of the lab was moved to a base in Maryland, and Pastore was moved to the other research group at Fort Monmouth, the Intelligence and Information Warfare Directorate. In this lab, they focused on signals intelligence, which involved intercepting radar signals. He worked on designing systems and antennas. He had no experience in designing antennas; however, they told him, “You have a Ph.D., go read a book and figure it out.”
When the second Iraq War began, Pastore was assigned the mission of detecting and neutralizing roadside bombs. This task was challenging because the United States military was designed to fight the Russians in Western Europe. In the Iraq War, the military was fighting people with no formal army. The enemy was also very smart and could make bombs out of anything. Some examples included wireless doorbells and long-range cordless phones. Every bomb was made differently, and the lab would receive bomb analysis results done in the field by FBI and CIA agents. The research lab in New Jersey could recreate the bombs and work to design solutions.
The types of bombs that Pastore’s lab was combating were made by placing an explosive inside a fake rock. When the fake rock was covered in sand it looked like any other rock in the desert, and these bombs were impossible to see visually. The bombs were wireless and triggered using a mechanism much like the motion detectors found in home security systems.
Pastore’s job was to find a way to set off the bombs before the military trucks got there. There were many constraints on the device they were developing. It had to be able to cause the bombs to detonate at least 50 feet before the Humvee reached the bomb while the truck was driving 60 to 70 miles per hour. This provided a window of only a few seconds for the device to work. Even if the device worked scientifically, there was no guarantee the soldiers would use it unless it met all of their needs.
It was important that the device was very simple. The lab was told to make it have only three buttons: on, off, and it’s working. Additionally, the final device had to run off of an allotted portion of the truck’s power supply, be a certain dimension, maintain its own cooling system, be sand-proof, and be developed within a specific budget. Creating a functioning device is more complicated than just perfecting the science, and Pastore worked with systems engineers to figure out how to put the science into a working and realistic system. The lab also received feedback from members of the army and worked to incorporate that into the final design.
Another project that Pastore worked on was a bomb/electronics detection system. The theory was to constantly send out an electronic signal, so when the signal hits an electronic object it bounces back to the truck. This device was beneficial because it looked solely for electronics. According to Pastore, if you are in the desert and you get a response, it means “there’s something there that shouldn’t be there.” The military convoy could then stop and assess the situation.
This system utilized the nonlinear response of semiconductor diodes. When two different frequencies enter a diode, they mix. This creates sum and difference frequencies. The diode will reradiate the mixed frequencies. If you know the signal being sent out, you know what to look for when it bounces back. The detection system could be applied to roadside bomb detection as well as in the detection of suicide bombers.
Pastore and the research team also considered several other bomb detection strategies. One included using the idea that a buried electronic device changes the consistency of the dirt. A large speaker mounted on the Humvee would then send out large seismic waves and constantly blast the ground until a laser vibrometer recorded a discrepancy. Another strategy was to consider the concept that a fake rock heats differently from a real rock, so an infrared camera could be used to locate bombs as they cooled at night.
Eventually, the United States military became so good at defeating the wireless bombs that the enemy switched to running long wires and using an old fashioned plunger and binoculars. Pastore’s lab was then assigned the task of figuring out how to detect a wire. One strategy used was to consider a wire as an antenna and make it reradiate as well.
The enemy was very smart and they were constantly changing their strategies, so the army had to constantly develop new technologies to combat them as well. The military didn’t always care about how things worked — they just cared that they did. Because it was all classified, Pastore could not publish any papers about the work he did. “The reward for working hard was more work,” he said.
Pastore enjoyed working for the military because of the real-world impacts and how he could see the project immediately become useful. He retired from his position in the research lab when the team was relocated to a base in Maryland. At that time, already teaching part-time at Stevens, he became a full-time member of the Physics department. Professor Pastore’s career in the military is a great example of how engineering and physics concepts can be applied in beneficial ways.
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