Sirius was founded by Martine Rothblatt, David Margolese and Robert Briskman. In 1990, Martine Rothblatt founded Satellite CD Radio, Inc. in Washington, DC. The company was the first to petition the FCC to assign unused frequencies for satellite radio broadcast, which "provoked a furor among owners of both large and small radio stations." Rothblatt had previously helped create the PanAmSat international satellite television system, and helped launch and served as CEO of the Geostar satellite navigation system. In April 1992, she resigned as chairman and CEO of Sirius in order to start a medical research foundation, focused on finding a cure for her daughter's illness. Former NASA engineer Robert Briskman, who designed the company's satellite technology, was then appointed Chairman and CEO.