Final answer:
The U.S. initially struggled to launch its first satellite with the Vanguard program experiencing multiple failures. The successful launch of Explorer 1 on January 31, 1958, marked the U.S. entering the space race after the Soviet Union's earlier Sputnik launch.
Step-by-step explanation:
As the U.S. attempted to launch its first satellite, it faced a series of failures through its Vanguard program, with early attempts resulting in crashes or explosions. This was happening during a period of intense competition with the Soviet Union, which had already successfully launched Sputnik in October 1957, marking the beginning of the space race.
In response to these initial setbacks, the United States doubled down on its efforts, and a second team, working with the Jupiter-C rocket, succeeded when on January 31, 1958, Explorer 1 became the first US satellite to reach space. This success reinvigorated the American space program and led to the establishment of NASA that same year, setting the stage for future endeavors into space exploration.