Margaret Hamilton stands next to a stack of Apollo Guidance Computer source code.
Credits: Courtesy MIT Museum

Forty-seven years ago, humans first set foot on the Moon during the Apollo 11 mission. That success would not have been possible if not for the team of 400,000 people who worked to ensure the success of the mission and the safety of astronauts Neil Armstrong, Buzz Aldrin and Michael Collins. One of those 400,000 people was Margaret Hamilton. On November 22, 2016, President Barack Obama awarded Hamilton the Presidential Medal of Freedom for her contribution that led to Apollo 11's successful landing. 

The very first contract NASA issued for the Apollo program (in August 1961) was with the Massachusetts Institute of Technology to develop the guidance and navigation system for the Apollo spacecraft. Hamilton, a computer programmer, would wind up leading the Software Engineering Division of the MIT Instrumentation Laboratory (now Draper Labs). Computer science, as we now know it, was just coming into existence at the time. Hamilton led the team that developed the building blocks of software engineering – a term that she coined herself. Her systems approach to the Apollo software development and insistence on rigorous testing was critical to the success of Apollo. As she noted, “There was no second chance. We all knew that.”

Her approach proved itself on July 20, 1969, when minutes before Armstrong and Aldrin landed on the Moon, the software overrode a command to switch the flight computer’s priority system to a radar system. The override was announced by a “1202 alarm” which let everyone know that the guidance computer was shedding less important tasks (like rendezvous radar) to focus on steering the descent engine and providing landing information to the crew. Armstrong and Aldrin landed on the Moon, rather than aborting the approach due to computer problems. In fact, the Apollo guidance software was so robust that no software bugs were found on any crewed Apollo missions, and it was adapted for use in Skylab, the Space Shuttle, and the first digital fly-by-wire systems in aircraft. Hamilton was honored by NASA in 2003, when she was presented a special award recognizing the value of her innovations in the Apollo software development. The award included the largest financial award that NASA had ever presented to any individual up to that point.

Today, Margaret Hamilton is being honored again – this time at the White House. President Obama has selected her as a recipient of the Presidential Medal of Freedom. The highest civilian award of the United States, it is awarded to those who have made an especially meritorious contribution to the security or national interests of the United States, to world peace, or to cultural or other significant public or private endeavors.

Watch the ceremony live or watch a recording on the official White House Web site.

Nicholas P. Russo
NASA History Division Intern, Fall 2016
Last Updated: Nov. 23, 2016
Editor: Andres Almeida