“Once you’re at Los Alamos you find out that there are interesting applications of basic physics,” he says. “A lot of people gradually end up spending more time on applications than on what they learned in grad school.” Byrd’s work is based on the need to verify whether other countries are adhering to treaties banning nuclear weapons testing. “The limited test ban treaty signed in the early 1960s is still the main treaty that applies to above-ground testing,” he says. “Nowhere in space or in the atmosphere is anyone allowed to test a nuclear weapon. The satellites that verify those treaties are the ones I work on.” He says it’s important to have more than one detection method in order to prove a treaty violation. “If it happens in the atmosphere, you will get an optical flash and a radio-frequency pulse, so you need RF and optical detectors,” he says. “In space, we look for x-rays, gamma rays, and neutrons. We have all those instruments on the satellites,” he says. “In the end we get almost everything there is to get. It’s kind of hard to sneak past the treaty.” Detection of underground testing is taken care of by other instruments, but Byrd says he also has to be familiar with underground detection in case a test happens at or near the surface, where it might send out signals through both the atmosphere and the Earth. In 2006, Byrd earned an MBA from the University of New Mexico. “At some point doing the technical work is not enough,” he says. “Somebody has to worry about how this whole thing fits together, not just in space but also in the atmosphere and down in the ground, and what’s going on in different labs. Those are not really technical questions.” He then completed a three-year assignment in Washington, working as the technical advisor for the program office in DC that does nuclear treaty monitoring. Today he is back in New Mexico, at Sandia National Laboratory, developing software to translate the outputs of the satellite instruments into usable information for the people who monitor them.