Margaret hamilton led the nasa software team that landed. The guidance computer used on the grumman lunar module was the first computer to use integrated circuits in its design. Project apollo features a nearfull implementation of the control panels in the command module and lunar module, and an increasingly accurate simulation of the internal systems e. Onboard flight software for the manned missions was developed for both the command and lunar module computers. Precedes all flown missions, but is distinguished by the fact that it is the last agc software that retains a full suite of selftest software, and is thus indispensable for validating software and hardware simulations of the guidance computer. A deep dive into the apollo guidance computer, and the hack that. Pgncs, and specifically its computer, were also the command center for all system inputs from the lm, including the kollsman instrument built alinement optical telescope, the radar system, the manual translation and rotation device inputs by the. A deep dive into the apollo guidance computer, and the. While the control system was analog, the navigation and guidance functions ran on a digital computer that was also used by the command and service module csm. Initially, the apollo guidance computer agc for both the command module and the lunar module were simulated functionally, just like the rest of the spacecraft hardware 20. Develop a system that can control a,000 kg spaceship, orbiting at 3,500 kilometres per hour around the moon, land it safely within metres of a specified location and guide it back from the surface to rendezvous with a command ship in lunar orbit.
The computer is functionally divided into seven blocks. The smithsonians national air and space museum holds in its collections the apollo flight guidance computer software collection above, page. The photo above shows how the core rope modules slid into the apollo guidance computer. The computer which landed apollo 11 on the moon was about. The computer wasnt designed for that amount of simultaneous input from both systems. Software for lunar missions consisted of colossus for the command module, whose development was led by frederic martin, and.
Here, margaret is shown standing beside listings of the software developed by her and the team she was in charge of, the lm lunar module and cm command module onboard flight software team. That code is all about positioning the antenna for the lr landing. There was one agc on each of the apollo command modules and another one on each lunar module. What were the problems on the apollo 11 lunar module. Footprints on the moon 30th anniversary of the moon landing. Similar source code and tools are provided for the verydifferent abort computer that resided in the lunar module. The lunar mission used a command module computer designed at mit and built by raytheon, which paved the way to fly by wire aircraft. Original apollo 11 guidance computer agc source code for command module comanche055 and lunar module luminary099. The nasagrumman apollo lunar module lm after descending to the lunar surface from lunar orbit, provides a base from which the astronauts explore the landing site and enables the astronauts to take off from the lunar surface to rendezvous and dock with the orbiting command and service modules csm. The apollo guidance computer agc is a digital computer produced for the apollo program that was installed on board each apollo command module cm and apollo lunar module lm. In the event that the lunar modules main guidance computer failed, the crew in the lm would switch to using the abort guidance system ags to get them back up to the command module. No, a checklist error did not almost derail the first.
Lance eliot, writing in forbes recently, noted that. They came up with a new way to store computer programs, called rope. The lunar module computer moon landing 40th anniversary. Apollo lunar module electrical power system overview. For the lunar modules abort guidance system ags computer, we have. The fourth computer was one which was never used on. One computer sat in the command module, another in the lunar module, just above the hatch that astronauts used to get onto the lunar surface. The team developed and incorporated novel lightweight materials and cutting edge electrical, communication, navigation, and computer hardware and software systems.
For a moment mission control faced a go nogo decision, but with high confidence in the software developed by computer scientist margaret hamilton and her team, they told the astronauts to proceed. Lem guidance, navigation, and control subsystem study guide march 1966 8. Finally, any supplemental software material we have been able to find or create for the saturn rockets launch vehicle digital computer or for the gemini onboard computer obc are provided, though these materials are minimal at. When apollo 11s lunar module landed on the moon 40 years ago today, the software that helped take humans to another celestial body was essentially built using papertape rolls and thick cardstock that was punched with special holes. The apollo guidance computer agc on board the command modules and lunar modules of the apollo missions had about as much processing power as a simple electronic calculator. Listing of software for apollo lunar module guidance computer. Software engineer john pultorak worked 4 years to build a replica of the apollo guidance computer agc, just so he could have one. But we do know that the software developed by hamiltons group allowed the overloaded lunar module computer to restart, shed unimportant tasks, and guide the astronauts to a safe landing. Perhaps the most remarkable example of the capabilities of the apollo guidance computer and the ingenuity of the engineers at the instrumentation lab occurred during the apollo 14 mission, when a faulty abort switch in the lunar module threatened a successful landing. How apollo 11 influenced modern computer software and hardware. The apollo lunar module lm, built by the grumman corporation in bethpage, ny, was the vehicle that would take two astronauts down to the lunar surface and return them to the waiting command module in. Oh, and luminary was only the lunar module software. We have the original agc software, in lots of different versions, including apollo 8, 11, and 17, transcribed into source code, both for the command module and for the lunar module.
The unplanned pause also allowed time for some software updates to be added to the lunar module computer. The grumman lunar modules ascent stages radar antenna also received transmissions from the command surface modules transponder and calculated the grumman lunar modules precise position and speed during docking. Margaret hamilton computer scientist nasa solar system. The underappreciated power of the apollo computer the. Footprints on the moon about the apollo computers abc. The underappreciated power of the apollo computer the atlantic. Dyer recalled an upgrade to the computer software on the airplanes. Lmags operating manual, flight program 6, july 1969, trw document 111766033t000, revision 1 38 mb pdf. Agc was the main computer system of the apollo program that successfully. Once in orbit, two of the threeman crew transferred from the csm to the lm. Lab who were responsible for developing the software for the apollo lunar module. Luminary is name of the mission software which was run on the apollo guidance computer installed in the lunar module lm in all of the later missions, apollo 10 through 17.
The goal is to be a repo for the original apollo 11 source code. Each apollo mission featured two agc computers one in the apollo command module and one in the apollo lunar module. Reportedly, aldrin later said he kept the guidance system on while the descent radar was also on. The rope mother margaret hamilton national air and. It is a complex consisting of an instructoroperator station, controlling computers, digital conversion electronics, external visual display equipment, and a fixedbase crew station. For those of us who developed the onboard software for the lm guidance computer lgc it was our first flight. Eagle lander 3d el3d is an authentic simulation of the apollo lunar landings and includes accurate renditions of scenery, flight dynamics and the lunar module. The agc provided computation and electronic interfaces for guidance, navigation, and control of the spacecraft. Source code for the apollo 11 guidance computer hacker news. The lunar module simulator was designed to train flight crews for the lunar landing mission. In an article in the lunar surface journal, paul adler, a lunar module software engineer, described working with another engineer, don eyles, to develop a software sequencer that effectively. Build your own apollo 11 landing computer universe today. Could the lem stack descent configuration be flown without any guidance program running in the lem guidance computer lgc.
Computer subsystem apollo guidance computer agc command module computer cmc on csm lm guidance computer lgc on lm identical hardware, different software colossus for csm, luminary for lm di l d k b d dskydisplay and keyboard dsky two csm dskys, one on main panel and one in lower equipment bay leb. Lm1, also known as apollo 5, was a 6hour unmanned mission in earth orbit for the lunar module lm only. Both the agc and its user interface named dsky were developed in the early 1960s by the mit instrumentation laboratory. The apollo guidance computer, in both its guisesone on board the core spacecraft, and the other on the lunar modulewas a triumph of engineering. An unusual feature that contributed to its small size was core rope memory, a technique of physically weaving software into highdensity storage. One of the first computers to use integrated circuits, the apollo guidance computer was lightweight enough and small enough 70 pounds and under a cubic foot to fly in space. The apollo command module cm and lunar module lm, were each equipped with a version of pgncs. The final lunar landing programs had eight coresets in the lem computer and just.
I worked on the software and i always liked the lunar module work so i kind of steered and stayed with the lunar module software from almost its inception up until the lunar landing all the software had to be tested rather exhaustively in order to make sure that it met all. The surprisingly funny code for the apollo moon landings. The agc was installed on both the apollo command module and the lunar module. Engineers remember the making of the lunar module asme. Apollo and the birth of software engineering hack the moon. Actually, the title of this webpage and this section, luminary, is a bit of a misnomer, since we dont limit ourselves to just luminary. It remained docked with the csm during apollos journey into a lunar orbit.
This meant that the major components of the apollo modules existed as software in a. Could the apollo lunar module be flown to a landing. The apollo guidance computer agc on board the command modules and lunar modules of the apollo missions had about as much processing power as a. If youre interested other flight computers used in the apollo program. It is a port of virtual agc by ronald burkey from c to javascriptasm. Her code got humans on the moonand invented software. Inspired by answers to could the lunar module have moved to a different spot. Hear more about the making of the lunar module on asmetechcast as an engineer, you couldnt want anything better than that. But once the descent to the lunar surface had begun, the rogue bit of solder could activate the switch, ordering the antares computer to try to rocket the lunar module back into orbit. Historians disagree about the cause of the famous computer alarms that nearly caused the apollo 11 landing to be scrubbed at the last minute. Hamilton stands next to listings of the apollo guidance computer agc source code. An 18inchthick printout in don eyless loft shows some of the computer code that controlled the apollo lunar modules descent to the moon. Moonjs is an online apollo guidance computer agc simulator. Digitized by the folks at virtual agc and mit museum.
The core rope module below and its companion held an early lunar module program called retread 50. Currently el3d includes apollo 11,12, 15, 17, a lm racing course and an orbital flight. Jim kernan computer engineering interviewing hack the moon. Apollo flight journal the apollo onboard computers. There was also a second backup computer system called abort guidance system ags on the lunar modules, which is simulated by virtual agc, but not the current version of moonjs. How did the apollo flight computers get men to the moon. I think the actual response to a total lgc failure would have been to abort. Margaret hamilton inside a mockup of the apollo command module. Apollo guidance, navigation, and control gnc hardware. When apollo 11s lunar module landed on the moon 40 years ago today, the software that helped take humans to another celestial body was essentially built using papertape rolls and thick cardstock that was punched with special holes it wasnt open source in the sense we know today, but it was built for nasa under contract, then was tested, modified and finetuned by nasa engineers in. Agc was the main computer system of the apollo program that successfully landed 12 astronauts on moon. When programmers at the mit instrumentation laboratory set out to develop the flight software for the apollo 11 space program in the mid1960s, the necessary technology did not exist.
Hamilton, now an independent computer scientist, described for mit news in 2009 her contributions to the apollo software which last month was. The code that took america to the moon was just published quartz. Neil armstrong manually landed the lunar module, which used just a couple of thousand. It wasnt open source in the sense we know today, but it was built for nasa under. Armstrong took manual control of the lunar module while. Even your smartphone is by far superior in computer power than were the lunar lander computers. James kernan worked on computer engineering and software during the apollo program at mitdraper. During the design of the guidance computer at mits instrumentation laboratory, buzz aldrin wanted the computer to be able to simultaneously handle radar data from the lunar surface and the apollo command and service modules in lunar orbit, just in case apollo 11 needed to abort the landing and rendezvous with the csm. This excellent apollo memoir, written by don eyles, the computer software engineer programmer who wrote the code for the apollo guidance computers landing programs for the lunar module titled luminary, is the closest laymen can come to understanding how the lunar modules electronic brain worked as it descended toward the lunar surface. Lunar module power system electrical control assembly subsystem 30 a lmp bus bat. The second was in the lunar module that would control the landing and then the ascent back to the command module and docking. On july 20, 1969, as the lunar module, eagle, was approaching the moons surface, its computers began flashing warning messages.
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