NASA, which was founded on July 29, 1958, has long used a huge countdown clock during mission launches. Initially, it used an analog display that stood across the river in Cape Canaveral to tick off the seconds until launch. Now, NASA uses a digital LED unit that measures nearly 26 feet wide by 7 feet tall. Countdowns allow astronauts and engineers to synchronize their moves during a rocket launch. Everyone is familiar with the “5, 4, 3, 2, 1, zero, liftoff!” that NASA can heard counting down in documentaries and films, but where did the idea come from? It was actually inspired by Austrian sci-fi filmmaker Fritz Lang. In 1929, he created a film called Woman in the Moon, which featured the idea of a countdown clock. In the film, the astronauts were getting ready for liftoff as the numbers on a large screen counted down. This geared up suspense associated with a launch in a cinematic way for the audience, before man ever hopped on a rocketship. However, many decades later, NASA began doing the same thing — starting with its first successful satellite launch, Explorer 1 in 1958. The method proved to be helpful in both keeping launch sequences organized and in communicating with the public. Today, NASA uses “L Minus” and “T Minus” — L minus time is how far we are from liftoff in hours and minutes, while T minus is the sequence of events that are built into the launch countdown. While all of NASA's missions had very different goals, there's one thing they all had in common: they were launched using NASA's famous countdown clock.
