A new probe of the humble electron may provide insight into the forces at work inside the heart of matter. Now, the MOLLER experiment at the U.S. Department of Energy's Thomas Jefferson National Accelerator Facility is one step closer to carrying out an experiment to gain that new insight. The experiment has just received a designation of Critical Decision 1, or CD-1, from the DOE, which is a greenlight to move forward in design and prototyping of equipment.