the American Institute of Chemical Engineers, and the Institute of Electrical and Electronics Engineers. Goertz's primary work and accomplishments revolved around the development and improvement of master-slave manipulator devices, but Goertz also devoted time to completing basic research on the degrees of freedom necessary for smooth motion by remote manipulation. He also created an initial prototype of a virtual reality device by developing one of the first head-mounted displays. For his work Goertz also codified terms so that university and industrial developers could replicate and contribute to his field, and he incorporated nautical terms into the lexicon of robotics, including pitch, yaw, and roll. The company of Central Research Labs in Red-Wing, Minnesota was created by Goertz's efforts and technological developments, and the company made more than 8,000 master-slave manipulators for entities in 26 different countries. Goertz was replaced in 1953 as head of Central Research Labs by Demetrius Jelatis. Today, the purpose of teleoperation has expanded beyond the scope of just safety and now includes uses such as reaching remote environments in space or deep underwater and working with manipulating extremely large or small objects for surgical operations or manufacturing, among many other uses. Master-slave manipulator device The goal of a master-slave manipulator is the protection of workers from radiation while enabling precise manipulation of materials. The machine can be thought of as two distinct devices, the "slave" and "master" arms. The "slave" arm is responsive to the controlling device, the "master" arm, with the benefit that through remote handling manual tasks can be performed without the need of direct human intervention. In nuclear settings the slave arm is located within a hot-cell and the master arm is located in a control room. Whenever the master arm is manipulated, the motion is reproduced precisely by the slave arm. While at Argonne National Laboratory Goertz developed the master-slave manipulator in order to safely handle hazardous material from the 100-B plutonium reactor at Hanford. The initial master-slave manipulator device was designed by Goertz in 1948 as a seven-degree-of-freedom bilateral (symmetrical) metal tape transmission pantograph device, which was operated through a leaded glass wall. In 1949 Goertz filed a patent for a mechanical, bilateral master-slave manipulator, and in 1951 Goertz improved upon this design with the first tel-operated articulated arm with a design that relied on mechanical coupling between the master and slave arms through the utilization of steel pulleys and cables.