In the 1960s, four thousand IBMers participated in Apollo missions, including Apollo XI. These researchers, engineers and programmers designed the computers and developed many complex software that helped land the crew on the Moon and then safely return them to Earth.
In particular, they worked alongside NASA flight directors to carry out the detailed analyses required to navigate from Earth to the Moon and from the Moon to the Earth. For example, the re-entry trajectory of Apollo XI was calculated 400 times during the mission. Apollo XI landed in the Pacific Ocean on July 24th 15 miles from its recovery ship.
Some have developed a global network of relay stations and ships to track and communicate with the rocket. Still others have invented and built the integrated circuit to miniaturize the equivalent of a mainframe.
Gene Kranz was the flight director in service on July 20, 1969, when astronauts Neil Armstrong and Buzz Aldrin separated the lunar module from Apollo (US) to begin their descent to the Moon. "The information on the systems we used to make our decisions was developed by IBM. Without IBM and the systems provided, we would not have landed on the moon."