Restoring the Apollo Lunar Module Guidance Computer...

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OneHungLow
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Restoring the Apollo Lunar Module Guidance Computer...

#1 Post by OneHungLow » Mon May 29, 2023 1:15 pm





So close on bingo fuel...
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Re: Restoring the Apollo Lunar Module Guidance Computer...

#2 Post by Karearea » Mon May 29, 2023 5:58 pm

^ Apollo 11: The Complete Descent - so moving to listen to that again. ^:)^

Thank you, OHL.
And with the morn, those angel faces smile...

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Re: Restoring the Apollo Lunar Module Guidance Computer...

#3 Post by OneHungLow » Wed May 31, 2023 8:21 am

Karearea wrote:
Mon May 29, 2023 5:58 pm
^ Apollo 11: The Complete Descent - so moving to listen to that again. ^:)^

Thank you, OHL.
It is a very evocative radio exchange isn't it. They came within seconds of having to abort. Extraordinary times.

I was moved to commence reading this...

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Re: Restoring the Apollo Lunar Module Guidance Computer...

#4 Post by Fox3WheresMyBanana » Wed May 31, 2023 8:46 am

Many thanks for the thread, OHL.

Meanwhile, in interstellar space....

https://voyager.jpl.nasa.gov/mission/st ... e_they_now

Voyager 1 is nearly 15 billion miles from Earth, 45 years after the launch on a mission designed to last 4 years.

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Re: Restoring the Apollo Lunar Module Guidance Computer...

#5 Post by OneHungLow » Wed May 31, 2023 9:09 am

I am always delighted when folks enjoy reading these little pieces of space and aviation history that give me so much pleasure too. I enjoy these along with the serendipitous learning that can be garnered from links like the one Fox3 posted ref. Voyager above.

I have just learned that programmer Don Eyles had to step up to the plate on the Apollo 14 mission as well.
Among his other achievements, Apollo 14 brought Eyles a special notoriety — including an invitation to the White House. Less than four hours prior to the planned descent from lunar orbit, the bright red Abort button on the LM's instrument panel illuminated and began sending a spurious signal to the computer that would have aborted Alan Shepard and Edgar Mitchell's landing at the moment the descent engine was ignited. Eyles had written the code that monitored that signal. At 1:00 in the morning he was called on to attempt to write a workaround for the problem, with no allowance for error. In less than two hours, not only did he write the workaround, but it was verified in simulators at both MIT and Houston, and then read up to the crew. That clever workaround simply changed a few registers, first to fool the abort monitor into thinking that an abort was already in progress, and then to clean up afterward so that the landing could continue unaffected. The procedure required inserting 61 precise and sequential keystrokes on the computer keyboard (the DSKY) under severe time pressure. Mitchell executed the procedure flawlessly and it worked perfectly. Apollo 14 landed at its target point on time, and the Apollo program once again proceeded without a major setback. An Apollo 14 failure, coming after the near-tragic failure of Apollo 13, would very likely have doomed my mission, Apollo 15, to a paper exercise. (Apollos 16 and 17 were already facing cancellation.) Eyles solved that problem — and thank goodness he did.
- Commander, David R. Scott Apollo 15

Eyles, Don. Sunburst and Luminary: An Apollo Memoir . Fort Point Press. Kindle Edition.






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Re: Restoring the Apollo Lunar Module Guidance Computer...

#6 Post by OneHungLow » Wed May 31, 2023 5:37 pm

I was somewhat perplexed at some of the claims made about Margaret Hamilton's role in the development of the lunar module software, preparatory to the Apollo 11 flight in the video first noted here...

viewtopic.php?p=367810#p367810

It seems that history has been rewritten to an extent in this case as Ms. Hamilton did not have a role in the LM software development prior to 1970, contrary to what was claimed on her company website at some stage.
Margaret Hamilton's role: Hamilton in 2016 received the Medal of Freedom from President Obama with a citation stating that she "led the team that created the on-board flight software for NASA's Apollo command modules and lunar modules." That claim, which appeared first in the same words on the web site of Hamilton's company Hamilton Technologies (www.htius.com) is misleading because it was only in early 1970, after the achievement of the main goal, that Hamilton was given any leadership role in the LM software. (The organization chart of the Apollo effort at the MIT Instrumentation Laboratory, dated Feb. 1, 1969, available at www.doneyles.com/LM/ORG [MITApolloOrg] snapshots the leadership structure of the Apollo effort at MIT during 1969.) Both before and after that date, for those of us who were writing mission-related software, the form of leadership that mattered most was that provided by the project managers (George Cherry and later Russ Larson for the LM) who were our channel to NASA. Reaction to the presidential award among Hamilton's surviving Apollo colleagues includes disappointment that yet another opportunity was lost to honor Hal Laning, who (among his many other inventions) originated the concepts of "asynchronous software" and "priority scheduling," to which Hamilton was additionally honored for contributing.
Eyles, Don. Sunburst and Luminary: An Apollo Memoir . Fort Point Press. Kindle Edition.
The observer of fools in military south and north...

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