Fifty years ago, on July 20, 1969, an awestruck world watched as NASA’s Apollo 11 astronauts, Neil Armstrong and Buzz Aldrin walked on the Moon for the first time. It was truly a colossal event!

But that would not have happened without NASA and its tremendous team of scientists, engineers and technicians—along with the help of 4,000 IBM employees who wrote software programs and developed the worldwide network of relay stations. The brunt of the workload for the Apollo 11 mission was handled by five System/360 Model 75 mainframe computers.

According to Gene Kranz, NASA Flight Director at the time, “The systems information we used to make the go, no-go decisions was developed by IBM, and the ultimate go, no-go decision that day was provided to me by computers operated by IBM engineers within NASA’s Mission Control Center. Without IBM and the systems they provided, we would not have landed on the Moon.”

Sure, it's fun to compare, but so what if my iPhone X is millions of times more powerful than all those five mainframes combined. The reality is: Apollo’s five System/360 Model 75 mainframe computers were powerful enough to guide three astronauts across 477,710 miles of space from the Earth to the Moon and back, safely.