The half-century-long effort to establish a planetarium in Washington, DC, reflects the evolving intersections of science education, national identity, and geopolitical strategy in twentieth-century America. Beginning in the 1920s, initial proposals aimed to educate the public about astronomy through advancements in German optical technology. However, as the Cold War intensified, the planetarium project took on greater significance, becoming a symbol of American technological prowess and a strategic tool amid ideological competition with the Soviet Union. The culmination of these efforts was the opening of the "Spacearium" within the National Air and Space Museum in 1976, coinciding with the US Bicentennial. This study explores how the development of the Spacearium was not just a scientific or educational endeavor but reflected broader cultural and political currents, ultimately serving as a platform for the United States to assert its leadership in science and technology on the global stage.