Interesting memoir by Don Eyles, who was a key member of the software development team for the Apollo lunar module descent phase software. He stresses the agility of the software team, where an astronaut could request a feature and the team could have new code ready for a simulator in days or weeks.
Put in today’s terms, the software team embraced a culture of continuous improvement, constantly looking for ways to eliminate nuisance alarms (prominent on Apollo 11), reduce fuel usage, refine navigation, etc. The team also developed EMPs (erasable memory programs) that astronauts could key in to deal with various hardware malfunctions. As part of continuous improvement, the software team developed and tested improvements, even when they knew that the changes would not be implemented by NASA configuration change boards.
To validate his software changes, Don flew many lunar landing simulations, all the way down to a simulated landing on the lunar surface. He continued in the space program after Apollo, developing Timeliner, the user interface language used on the International Space Station.
A couple of interesting quotes from the end of the book:
“Were we lucky or were we good? Both I think. To a point we made our own luck. The main ingredient in that was honesty, with ourselves above all.”
Referring to the o- ring issue that led to the loss of the Challenger space shuttle: “I saw the root cause of the accident in a failure of intellectual honesty.”
Referring to failures on the Hubble space telescope and the loss of the Columbia space shuttle: “those seemed to be further signs of the demise of the culture that had taken us to the Moon and back.”
Referring to the current NASA culture: “so management heavy that a decision that Allan Klump and I could make on our own in an afternoon might require a committee and a month.”
If you’re interested in the space program, engineering, or software, read this book. An interesting account by someone who lived it.