On-board flight software for the manned missions was developed for both the Command and Lunar Module computers. In addition to the operating system, the AGC had both an assembly language and a sophisticated software interpreter developed at the MIT lab that could handle more complex ‘pseudo’ instructions than the AGC. These instructions could simplify navigation programs and handle complex navigation equations in the background so as not to overwhelm the AGC power and memory capabilities.

The famous 1201 and 1202 priority alarm displays that interrupted and replaced the astronauts' normal displays with the Priority Displays during the Apollo 11 lunar descent signaled executive overflow was caused because the rendezvous radar was left on during the landing sequence and was stealing precious “cycles” from the AGC. This is in fact exactly what the computer and the software were meant to do– The MIT IL team (led by Margaret Hamilton) had intentionally designed the software with a priority scheduling capability that could identify the most important commands and that allows those to run without interruption pushing less important commands to the side.

The story about the Apollo 11 landing and the Priority Displays was one of error detection and recovery in real time. It was about the astronauts, mission control, the software and the hardware; and how they all worked together during an emergency as an integrated system of systems. It was about creating new, man-machine and software engineering concepts to do things never done before. Unlike a system where the software (or hardware) might "know" of a serious problem without the pilot's knowing it, the Priority Displays were able to determine right away if a particular alarm had occurred that fell within the category of an "emergency alarm" and they let the astronauts know about it too.

No known software errors ever occurred during any of the Apollo missions. The AGC software influenced the design of systems and software for future spacecraft including Skylab, the Space Shuttle and digital fly-by-wire aircraft systems.

How did a prototype keyboard earn its wings?

NASA and the engineers at the MIT Instrumentation Lab were tasked with creating a guidance computer that would help guide the spacecraft to the moon and back. They decided to go with a completely digital system—something that had never been done before. The Apollo Guidance Computer (AGC) became the central computer for the Apollo missions. But astronauts still needed an interface, something sturdy enough to withstand the rigors of space travel and simple enough for the astronauts to understand.

This was the birth of the DSKY, a leap forward in computer science. Standing for display/keyboard and pronounced “diskey,” the world’s first computer keyboard was developed by Ramon Alonso and his team. The DSKY “was simply a keyboard you find on any computer.” It had a digital display with big buttons and communicated with the AGC via a verb-noun interface. Software engineer Alan Green and his team developed the program that would support the astronauts communications with the computer. Astronauts would punch in the numbers for the action they wanted to take and the program they wanted to affect. This interaction “took the form of a grammatical conversation,” easy enough to use for people in the 60s who had never seen a computer before.

Though it eventually became the interface for the Apollo missions, the DSKY was just a prototype. Alonso and his team never expected it to stick. “And a funny thing began to happen,” Alonso said in an interview, “as we demonstrated ‘Fire Rocket,’ or ‘Display Time,’ or ‘Align Platform,’ some of the big shots would ask, ‘this Verb and Noun, is it going to stay, and fly to the moon?’” Some remarked that it wasn’t scientific or mathematical enough. Despite the odds stacked against it, the DSKY proved to be a reliable tool and contributed to every manned mission to the moon. From humble, linguistic origins to a memorial in the stars, the DSKY is responsible for the success of the Apollo missions.

A space race reading list

NASA Administrator Jim Bridenstine has revealed why Apollo-era technology from the 1960s is no longer good enough to land on the Moon today. ///

Not reusable, limited orbital trajectory (~10° of lunar equator), incompatible with partner nations' systems.

The moon landing was one of the most important moments in the history of computing, laying the foundations for everything from fly-by-wire cockpits to the smartphones in our hands. //

Programmer Who Landed Us on the Moon
Play Video
MOON LANDING
Apollo 11 Had a Hidden Hero: Software
The moon landing was one of the most important moments in the history of computing, laying the foundations of much of our digital world
By Robert Lee Hotz
July 14, 2019 9:10 pm ET

Yes, in 1969 the internet was still 14 years away, the World Wide Web wouldn’t show up until eight years after that and wouldn’t become a “thing” for the masses for yet another five years or so.

But the Apollo 11 mission couldn’t have happened without computer code—software. As the Wall Street Journal put it a couple of weeks ago: “It took more than big rockets to put humans on the moon … It took code.”

The fecal collection system presented am even more distasteful set of problems. The collection process required a great dead of skill to preclude escape of feces from the collection bag and consequent soiling of the crew, their clothing, or cabin surfaces. The fecal collection process was, moreover, extremely time consuming because of the level of difficulty involved with use of the system. An Apollo 7 astronaut estimated the time required to correctly accomplish the process at 45 minutes. Good placement of fecal bags was difficult to attain; this was further complicated by the fact that the flap at the back of the constant wear garment created an opening that was too small for easy placement of the bags.

Reflecting on humanity’s first steps on the lunar surface, fifty years after the epochal event.

Between the high-stakes maneuvers, the crew joked around, listened to music, and drank way too much coffee.

When, exactly, did the astronaut set foot on the moon? No one knows. //

And yet for all that precision, no one can say with absolute certainty when, exactly, Neil Armstrong first set foot on the moon. //

The night of the moon landing, NASA told the press that Armstrong had stepped onto the lunar surface at 10:56:20 p.m., and The New York Times reported that same time stamp on its front page the next morning. The real-time transcription of the mission’s air-to-ground voice transmission suggests that Armstrong took the step sometime between 10:56:43 and 10:56:48. And when NASA’s official Apollo 11 mission report went public in November 1969, it pinpointed first contact at five seconds earlier, at 10:56:15. //

Heiko Küffen, a German software engineer and space enthusiast, first came across this discrepancy in 2009, while trying to design a homemade real-time tracker that he could use to relive the moon landing for its 40th anniversary. //

To synchronize the transcripts and the recordings, Küffen made what he calls “reasonable assumptions,” which nearly a decade later he has yet to see contradicted. Armstrong, he found, first set foot on the moon at 10:56:25—closer, in other words, to the almost universally dismissed time given to the press that night than to the time produced by the mission report’s months-long analysis.

Apollo vet Sy Liebergot shows Ars how NASA got men safely to the Moon and back.

Lee Hutchinson - Nov 1, 2012 1:45 am UTC

it’s only a short drive to one of the high points overlooking Lebanon. It’s an astonishing sight. You look one way—toward Israel—and see nothing but blooming farms. You turn toward Lebanon and see nothing but barren hills with a sprinkling of Hezbollah flags and gun emplacements.

Why the disparity, since the land is basically the same? The congresswomen would probably explain it as due to Israel’s supposed oppression of the Palestinian refugees who live by the border or something like that.

They’d better start holding their ears, because it’s well documented that Palestinians are treated considerably better in Israel than in Lebanon. A 2017 Associated Press report tells us, but not the congresswomen apparently, that “Lebanese law restricts Palestinians’ ability to work in several professions, including law, medicine, and engineering, and bars them from receiving social security benefits. In 2001, the Lebanese parliament also passed a law prohibiting Palestinians from owning property.”

None of this is true in Israel, of course, where a Palestinian served on the Supreme Court. Actually, he was the second one. Would Omar and Tliab like to meet him? Probably not. Would they like to meet a Jewish judge at one of the 45 Islamic countries? Oh, wait. None of them have Jews any more.

Video clips from Podcast "13 Minutes to the Moon"

How the first moon landing was saved. The full story of the people who made Apollo 11 happen and prevented it from going badly wrong. Theme music by Hans Zimmer. Episodes released weekly.

• Updated: weekly
• Episodes available: indefinitely

Your handy reference to each station in the Apollo Mission Control room.

COMMENT:

"Name one thing that has come from "space exploration" that we couldn't do without. Tang?"

You probably misunderstood.

Well, many did.

Background of the problem:

Sweeney had the devil of a time during his bombing run. Nagasaki was his secondary target, and he had reluctantly headed for it when he could find no break in the cloud cover over his primary target of Kokura. When he reached Nagasaki, and finally found a brief opportunity to drop "Fat Man," because of where it was released, it ended up detonating over the industrial heart of the city, instead of the vast, sprawling suburbs. These suburbs happened to be separated from the industrial heart of the city by hills and valleys.

Even though "Fat Man," a plutonium device, was about twice as powerful as the uranium 235 bomb that had completely destroyed Hiroshima three days before--"Fat Man's" detonation only yielded about half as many casualties.

You see, for a nuclear weapon to be a credible deterrent, it must be understood that the bomb will be placed at a precise, predetermined location.

The German V2 had proved, beyond the shadow of a doubt, that a warhead-tipped ballistic missile could defeat any anti-aircraft defense anyone could devise. A fleet of fighters planes, indeed even fighter jets, and concentric circles of the most powerful antiaircraft cannons ever developed could not stop a V2 from dropping its payload. And it could do so with with no more than a few seconds warning.

Where a bomber could not get through, a V2 could. It had proved unstoppable during the war.

But V2s weren't accurate at the relatively short range from Peenemünde to London. The problem was vastly more formidable at a distance like that between Washington and Moscow, for instance.

And that fact reveals the value of space exploration.

In 1957, the Soviet Union put up a small radio emitting satellite into low earth orbit with their version of the new, improved V2 rocket. Sputnik orbited the earth in such a way that it traveled over nearly every major city on the globe before its batteries died and its elliptical orbit decayed and brought it back to the surface. People in New York and Virginia, et al, looked up at the sky in terror as Londoners had just 12 years before.

But the Soviets did not demonstrate they could bring Sputnik down at a precise, predetermined location. Their V2s were not credible threats yet.

The Soviets needed to demonstrate that they could put up a Sputnik, and drop it directly over the Washington Monument. America needed to prove they could launch a V2 into orbit and drop it over Red Square.

The race was on.

America, being populated by the greatest marketers the world had ever produced (think Kellogg's Cereal, Elvis and the Beatles here), decided to beat the Soviets by winning the Hearts and Minds of the world. The USSR made no pretense: their space program was run entirely by their military. The US decided to pretend that its own "space program" was a non-military civilian venture.

NASA was born.

Never mind that NASA inherited its missile technology program from the classified military program. Never mind that all of America's astronauts were Air Force officers.

It was still sold as a civilian-government venture. And lots of people bought it.

Heh.

But its primary goal was to show that it could launch a missile into orbit, and bring down a payload at a precise location. By 1961, the US was beginning to demonstrate success. Allan Shepard completed one orbit of the earth. John Glenn orbited the earth 3 times in 1962. But when their capsules splashed down it was only within about 50 miles of target.

But we and the Soviets were getting closer.

John Kennedy, a consummate Cold Warrior, began to think of the Moon as the "ultimate high ground."

The idea of putting up orbiting missile platforms was thought to be the Checkmate move in the race for effective nuclear weapons delivery systems.

The problem with orbiting platforms was they were just too damned provocative. There was just no way to put one up in orbit and pretend it was for a peaceful or benign purpose. We would never allow the Soviets to put up a missile platform over us, and likewise, they would be willing to go to war if we ever tried to put one up over them.

Hence, the Moon.

The Moon isn't in geosynchronous orbit over earth, but it is tidal locked. Moscow slides underneath of it once every day. Whoever got to the Moon first could then threaten to build or secretly build a missile base, and achieve the same checkmate that an orbiting missile platform would achieve.

This was Kennedy's aim, and this was the urgency behind the project.

The problem was, just as Neil Armstrong was misspeaking the most famous sentence ever uttered from the surface of the Moon, the defense department contractors had perfected the solid rocket fuel Minuteman III intercontinental ballistic missile. Suddenly, the US could launch a low maintenance missile from a silo in Iowa, and it could drop its payload over Red Square about 30 minutes later.

The problem with the Moon is it's really, really, really far away. 250,000 miles.

Most people think of the relationship between the earth and the moon as this:

O__o

In reality, it is more like this:

O___0

It takes days to go that far.

30 minutes, 1 1/2 days. It was a no brainer. We didn't need missile bases on the Moon anymore.

So, to the dismay of everyone who had bought into the marketing that made everyone believe NASA was a cross between Queen Isabella, Lewis & Clark and Sir Edmund Hillary, the astronauts played a couple of rounds of golf on he Moon, and then left, never to return.

You're right that there's nothing of value on the Moon.

But there are other reasons for exploring space and improving rocket technology.

The greatest goal within our reach today is SBSP, of course. SBSP is the very essence and sine qua non of man's future.

But there are many other reasons as well.

They were looking for a direct route to India, and found oh so much more back in 1492 when Columbus sailed the ocean blue.

It's not a waste of time. It never has been, even with our shifting priorities, needs and goals as a people and a nation.

Men will continue to venture into space whether you think it's a waste of time and resources or not.

And it's not.

But it's never going to be what you expected.

COMMENT: "Space exploration" is government waste on steroids.

REPLY:

"I think there is a world market for maybe five computers." -- Thomas Watson, chairman of IBM, 1943.
"Where a calculator on the ENIAC is equipped with 18,000 vacuum tubes and weighs 30 tons, computers in the future may have only 1,000 vacuum tubes and weigh only 1.5 tons." -- Popular Mechanics, 1949
"I have traveled the length and breadth of this country and talked with the best people, and I can assure you that data processing is a fad that won't last out the year." -- The editor in charge of business books for Prentice Hall, 1957.
"But what...is it good for?" -- Engineer at the Advanced Computing Systems Division of IBM, 1968, commenting on the microchip.
"There is no reason anyone would want a computer in their home." -- Ken Olson, president, chairman and founder of Digital Equipment Corp., 1977.
"640K ought to be enough for anybody." -- Attributed to Bill Gates, 1981, but believed to be an urban legend.
"This 'telephone' has too many shortcomings to be seriously considered as a means of communication. The device is inherently of no value to us." -- Western Union internal memo, 1876.
"The Americans have need of the telephone, but we do not. We have plenty of messenger boys." -- Sir William Preece, chief engineer of the British Post Office, 1876.
"The wireless music box has no imaginable commercial value. Who would pay for a message sent to nobody in particular?" -- David Sarnoff's associates in response to his urgings for investment in the radio in the 1920s.
"While theoretically and technically television may be feasible, commercially and financially it is an impossibility." -- Lee DeForest, inventor.
"The concept is interesting and well-formed, but in order to earn better than a 'C', the idea must be feasible." -- A Yale University management professor in response to Fred Smith's paper proposing reliable overnight delivery service. (Smith went on to found Federal Express Corp.)
"Who the hell wants to hear actors talk?" -- H. M. Warner, Warner Brothers, 1927.
"I'm just glad it'll be Clark Gable who's falling on his face and not Gary Cooper." -- Gary Cooper on his decision not to take the leading role in "Gone With the Wind."
"A cookie store is a bad idea. Besides, the market research reports say America likes crispy cookies, not soft and chewy cookies like you make." -- Response to Debbi Fields' idea of starting Mrs. Fields' Cookies.
"We don't like their sound, and guitar music is on the way out." -- Decca Recording Co. rejecting the Beatles, 1962.
"Radio has no future. Heavier-than-air flying machines are impossible. X-rays will prove to be a hoax." -- William Thomson, Lord Kelvin, British scientist, 1899.
"So we went to Atari and said, 'Hey, we've got this amazing thing, even built with some of your parts, and what do you think about funding us? Or we'll give it to you. We just want to do it. Pay our salary, we'll come work for you.' And they said, 'No.' So then we went to Hewlett-Packard, and they said, 'Hey, we don't need you. You haven't got through college yet.'" -- Apple Computer Inc. founder Steve Jobs on attempts to get Atari and HP interested in his and Steve Wozniak's personal computer.
"If I had thought about it, I wouldn't have done the experiment. The literature was full of examples that said you can't do this." -- Spencer Silver on the work that led to the unique adhesives for 3-M "Post-It" Notepads.
"It will be years -- not in my time -- before a woman will become Prime Minister." -- Margaret Thatcher, 1974.
"I see no good reasons why the views given in this volume should shock the religious sensibilities of anyone." -- Charles Darwin, The Origin Of Species, 1869.
"With over 50 foreign cars already on sale here, the Japanese auto industry isn't likely to carve out a big slice of the U.S. market." -- Business Week, August 2, 1968.
"That Professor Goddard with his 'chair' in Clark College and the countenancing of the Smithsonian Institution does not know the relation of action to reaction, and of the need to have something better than a vacuum against which to react--to say that would be absurd. Of course, he only seems to lack the knowledge ladled out daily in high schools." -- 1921 New York Times editorial about Robert Goddard's revolutionary rocket work. The remark was retracted in the July 17, 1969 issue.
"You want to have consistent and uniform muscle development across all of your muscles? It can't be done. It's just a fact of life. You just have to accept inconsistent muscle development as an unalterable condition of weight training." -- Response to Arthur Jones, who solved the "unsolvable" problem by inventing Nautilus.
"Ours has been the first, and doubtless to be the last, to visit this profitless locality." -- Lt. Joseph Ives, after visiting the Grand Canyon in 1861.
"Drill for oil? You mean drill into the ground to try and find oil? You're crazy." -- Workers whom Edwin L. Drake tried to enlist to his project to drill for oil in 1859.
"Stocks have reached what looks like a permanently high plateau." -- Irving Fisher, Professor of Economics, Yale University, 1929.
"There is not the slightest indication that nuclear energy will ever be obtainable. It would mean that the atom would have to be shattered at will." -- Albert Einstein, 1932.
"The bomb will never go off. I speak as an expert in explosives." -- Admiral William Leahy, U.S. Atomic Bomb Project.
"Airplanes are interesting toys but of no military value." -- Marechal Ferdinand Foch, Professor of Strategy, Ecole Superieure de Guerre.
"There will never be a bigger plane built." -- A Boeing engineer, after the first flight of the 247, a twin engine plane that holds ten people.
"Everything that can be invented has been invented." -- Attributed to Charles H. Duell, Commissioner, U.S. Office of Patents, 1899, but known to be an urban legend.
"Louis Pasteur's theory of germs is ridiculous fiction." -- Pierre Pachet, Professor of Physiology at Toulouse, 1872.
"The abdomen, the chest, and the brain will forever be shut from the intrusion of the wise and humane surgeon." -- Sir John Eric Ericksen, British surgeon, appointed Surgeon-Extraordinary to Queen Victoria 1873.

Apollo 11 astronauts Neil Armstrong and Edwin E. “Buzz” Aldrin, the first men to land on the moon, plant the U.S. flag on the lunar surface, July 20, 1969. Photo was made by a 16mm movie camera inside the lunar module, shooting at one frame per second. (Nasa via AP) Remembering Tranquility Base. It’s been 48 years since we heard those famous words announcing that | Read More »

Panorama view of Apollo 16 lunar surface photos as lunar module pilot Charles M. Duke Jr. is photographed by commander John W. Young collecting lunar samples at Station No. 1 during the first moonwalk of the mission at the Descartes landing site. The panoramas were built by combining Apollo 16 images starting with frame AS16-114-18416 thru end frame AS16-114-18431. The panoramic images received minimal retouching by NASA imagery specialists, including the removal of lens flares that were problematic in stitching together the individual frames and blacking out the sky to the lunar horizon. These adjustments were made based on observations of the Moon walkers who reported that there are no stars visible in the sky due to the bright lunar surface reflection of the Sun. With significant overlap and time delay between frames, it is possible to create two different versions of this panorama with astronaut Charles Duke (Apollo 16) in the center (jsc2012e052598) and both in the center and walking away to the right (jsc2012e052599).

Explore this photo album by NASA Johnson on Flickr!