After World War II ended in 1945, the United States and the Union of Soviet Socialist Republics (U.S.S.R.) competed to become the most powerful nation in the world.
The rivalry extended to many areas, industrial power, military strength, and achievement in the arts and sciences. Space became a vast testing ground, a place where one society could prove its superiority over the other.
In 1957, the Soviets launched Sputnik I, the first man-made satellite to orbit the Earth. The Soviets were triumphant and the United States was stunned. Since then, both nations have devoted enormous resources and manpower to achieving milestones in space. The race was on.
The speed of sound is known as Mach 1. However, sound can travel through the atmosphere at varying speeds at different places and times, depending on the air pressure and air temperature. Experiments and calculations in 1986 determined that at freezing temperatures, in dry air, sound travels about 741.1 miles an hour.
At around 60 degrees Fahrenheit, sound travels faster, about 760 miles an hour. When Chuck Yeager flew his Bell X-1 and broke the sound barrier, the speed of sound in his area was 662 miles per hour. His craft eventually reached Mach 1.06, or about 700 miles an hour.