Hal Laning: The Man You Didn’t Know Saved Apollo 11
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- Опубліковано 22 тра 2019
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Special thanks to wehackthemoon.com/ for helping make this episode possible. Be sure to check out wehackthemoon.com/ for more behind-the-scenes looks and unsung heroes of the Apollo program.
This video has a lot to it. If you're like me and take things in better when you read, check out my companion blog post over on Discover.
And more even older space in my book, BREAKING THE CHAINS OF GRAVITY! You can order your copy on Amazon: bit.ly/astbtcog
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Finally, someone from my generation who knows who Hal Laning was and recognizes his brilliance.
Hal, a good name for someone engineering computers.
@Francois Lacombe
So in the book and the film, HAL kills the crew (except Dave Bowman); in the Apollo mission Hal saves the crew and the mission.
Art imitates life... life disregards art... sort of.
😉
@@PercivalBlakeney Have you seen 2010? HAL redeemed himself when Jupiter imploded. :)
@Christopher U.S. Smith
I'd forgotten about that, turning Jupiter into the dwarf star "Lucifer" (or at least helping the monoliths get the job done 😎).
It's explained a lot better (*explained* full stop) in the book. HAL kills the rest of the crew because he has been instructed to keep the real mission objective secret... i.e. the real possibility of extra terrestrial civilisation(s).
When Dave and Frank get close to uncovering that something's wrong, HAL panics (like anyone could do), kills the Junonauts in the Hibernacula, kills Frank replacing the Antenna Alignment Module and it's basically luck that saves Dave Bowman.
Essentially HAL had been programmed to keep the mission secret... no one had told him to NOT kill in order to accomplish that goal.
Like Dr. Chandra says "HAL was told to lie when he didn't know how to... he was told to lie by people who find it easy to lie" ... or words to that effect.
If you've not read the book of 2001, I recommend that you do; there's so much in the film that only becomes clear once you've read the source material.
Thanks for letting me show off, you're very understanding. 😊
@@PercivalBlakeney The movie was pretty good, but the book was fantastic. Wright Flyer, USAF (1968-1972).
All these worlds are yours, except Europa. Attempt no landing there. Use them together. Use them in peace.
One of the better 1201 / 1202 Alarm explanations I've heard. The Graphics were very helpful :)
The reason they kept popping was Buzz had the rendezvous program running in case they had to abort but the main computer wasn't designed to track another spacecraft AND a landing zone at the same time
@@dosmastrify You got this info from In the shadow of the moon documentary? I don't think this was Buzz choice, it was written on a checklist.
So that's what was buzzing on the screen...
I’ve just finished Gene Kranz’s book, Failure is not an option... He reports the same thing from a different angle... apparently the SimSup tried to throw a spanner in the works on the last sim before the flight of Apollo 11... everyone was expecting an easy ‘milk run’ simulation to build morale and settle everyone down for the impending launch. Instead, the sim team found an obscure computer error to throw in during the lunar descent - during the sim (with the white team and the backup crew) , the controllers called an abort based solely on this error code- a no no as the done thing was to abort only based on 2 separate data sources... the single error code which led to the abort? The 1202 alarm... it was so obscure that the controllers went away and read up on it... good job really - their new familiarity with the 1202 alarm allowed them to keep giving the ‘go’ as they came in...
I'm in the middle of the same book and just read about this part as well. The thing that confused me is, I was under the impression that the 1202/1201 were a surprise to the controllers.
I also read "Go, Flight" by Milt Heflin and Rick Houston, but in their version they attributed the success of the mission to a lone controller recalling the obscure code years back. If my memory is correct, they named John Aaron as this controller. There was no mention of a simulation run that brought these codes to the table.
It's really thrown me through a loop because these two books, written by very reliable sources seem to differ on the origin of how these program alarms were learned about.
I'll keep looking into it, and I'll even try to look back into Go, Flight to see if I can read over its version of things.
@@LandscapeAhoy129 My understanding from the Failure is not an Option is that it was Steve Bales who resolved the computer code error on Apollo 11. John Aaron is well know for the "SCE to Aux" call after Apollo 12 was struck by lightning shortly after liftoff.
Apollo guidance computer has encountered an unexpected problem and had to close.
Would you like to send an error report?
Imagine a BSOD
lol we are going back. Wait till they get stuck on a update! :)
Imagine rebooting the AGC and then having to wait for Steam to install updates.
@@ShaneSemler Linux!? The kernel has gotten way too heavy. I'd go for a micro-kernel RTOS like QNX or something similar. A micro-kernel is the surest way to certain of every line of code.
@@CarFreeSegnitz And woven into core rope memory to avoid frying fragile silicon chips. ;)
"Open the Command Module door Hal."
"I'm afraid I can't do that Dave."
@Kuntor Kunty Someone beat you to it again, Wankor Wanky, so retract your docking probe. ;-)
*blows open hatch*
@@kellyweingart3692 >>> *_"DON'T BLOW THE HATCH!"_** -- MAROONED [1969]* 😊
That was Apollo 15 and it was Al.
A concise and accurate explanation of a complex issue even for today's computer geeks. Well done, Amy!!! Another example of why you're the best!
I have seen many in-depth explanation videos of this Apollo nav computer numerous times through the years. THIS one blows them ALL away. Best explanation yet. Great job.
Good job explaining the concept of preemptive multitasking! I had no idea they implemented it this long ago.
It wasn't exactly preemptive. The main part was cooperative multitaksing with a part - called the "waitlist" which took care of interrupts. The usual thing a waitlist job did was either to change the value directly or to schedule a an ordinary task to take care of that event.
For those who don't know the difference preemptive - cooperative:
preemptive means, that the operating system can take away the processor at any given time from a task and assign it to another task. Usually this is done by having a sort of system clock interrupt which fires in regular intervalls and the task change is done no matter in which state a specific task currently is.
cooperative means that the OS doesn't do that, but instead the whole system relies on a cooperative behaviour of all tasks to release the processor as soon as possible. This means that eg. a task is not allowed to actively wait on some event in a loop. Instead it has to give back control to the operating system and continue the next time it runs where it left off.
In the AGC this also meant that in some tasks which had to do a lot of computation work, this work had to be split into subsections with a return to the operating system inbetween. A major reason for that was of course that most of the delicate mathematical computations (as eg. required by the guidance equations) where coded in the interpreter language which run much slower then native code.
preemptive operating systems have the beauty that the programmer can code a task just as he would do it when his task is the only thing the computer has to do. But this creates some additional problems, since now a task has to take into account that some variables might change unexpectetly while the algorithm runs (because the task might be interrupted at any time and another task might change some values). This goes down to the deepest level, where memory accesses must be guaranteed to be atomic. All in all, in preemptive multitasking there are a lot of possibilities to screw up the whole system and those problems are extremely hard to debug.
Those problems are not an issue with cooperative multitasking, since every task is guaranteed to be able to finish computation but of course no task is allowed to be stubborn and must return control to the operating system in time. State machines are a great way to achieve this behaviour.
It's amazing how much there still is to discover about those early programs and the extraordinary people that made them work. Thanks, Amy!
A great clip Amy. very informative. I'll have to watch it a few times to fully get the fine points. Nice to see you back. I hope you never run out of topics of discussion. This one is really fun.
I remember Apollo 11 well because in 1969 I was a radio operator at MacDill AFB in Tampa so I tuned all NASA frequencies on my Collins Scope radio system, using a dummy antenna so as not to interfere with NASA transmissions. I turned on the B&W TV with no volume and turned off all the station lights. Wow, the only illumination came from the TV and the multi-colored lights on my console and the only sound came from NASA. It was truly a day to remember! But I never heard of Hal Laning--until now. Thank You! Wright Flyer, USAF (1968-1972).
Fascinating!! Thank you for highlighting one of the thousands of individuals who made significant contributions to our space program. Keep these coming =)
LOVE these "behind the scenes" peeks into space history! Thanks Amy!
Aldrin later admitted that the 1201 and 1202s were his fault: he'd left the rendezvous radar active and that was the source of the excess demand. (He used it during the LM separation and station keeping activities before powered descent to provide an alarm if the distance had accidentally started decreasing- a task which didn't involve much activity...but when they separated during the descent mode the radar couldn't find the CM and basically went crazy looking to reacquire something that *wasn't there*. He'd simply forgotten to turn it off, which is why it was eating up all the computational capability...i.e. it was lost and trying like hell to find something to range on.)
As a hobbyist programmer, everything you said makes perfect sense. Amazing explanation!
I would say "few" have heard of Hal. Those of us with a long experience with the Space Program have definitely heard of him.
I thought I knew all about the 1201 and 1202 alarms already, but you managed to bring new info to me as well. Fantastic, keep up the good work.
Always interesting and informative, so glad to have you back 😀
Steve.
ua-cam.com/video/zCz29RWSqhQ/v-deo.html please explain this...looking for ANSWERS that's all
Why'd you sign your comment dude. Lmao
Love to see you back , you are so delightful !
What a great vid! My dad was one of the many engineers, unknown, unrecognized, but created an incredible program that challenged and excelled the conventional thinking...lessons of which, are still be relearned today by the new engineers who have forgotten history.
Make sure dad doesn't spill the beans on the "hoax". Hillary has a **lot** of time on her hands these days...
Most amazing journey.
Brilliant man. Unfortunately, in just seven days marks his passing seven years ago. At least he went knowing how hard we're working now to prepare for more exploration. That's all I want in life, to know that I worked on something that others find important enough to continue.
Thank you for this tribute, Amy.
I'll join the horde happy to see you back. As always, not just a deep dive, but an interesting choice of topic ordering, your usual incredible word choice, and precision diction that results in that rare combination of clarity and accuracy.
Thank you for sharing with us.
Excellent video Amy! Welcome back!
I was listening to the "Mission To Mars" theme when your "alert" popped up in my mail box.....Very Celestial....Hard to believe this coming July will be The 50th Anniversary of The Apollo 11 Moon Landing!! I still remember watching this as a young boy late at night with my Family and especially my Dad , who at the time was a Lt. Col. in the Air force and had gone to Flight School with his friend Gus Grissom so no doubt this was bitter/sweet for him. As always Amy your video's are literally OUT OF THIS WORLD.....Us FANS are so lucky for this channel. Cheers From Ohio...Home to Neil Armstrong
She is definitely (Out of this world) !!!!!
I made the request 3 years ago to explain and elaborate about the 1201 and 1202 alarm....and now I got it ....worth waiting..thanks. And thumbs up 👍🏻👍🏻👍🏻
Happy to see you back!
Great job, Amy. I have a real interest in the people and organizations that worked behind the scenes in the race to the Moon, so this was a welcome entry.
Let's hear it for those important men and women whose self discipline and passion help lead the way for Apollo and further space exploration when we needed it and laid the foundation for the future of space flight.
This was one of your best videos! Very informative and simple to follow.
Bravo! Your explanations of the computer operation are clear and concise. As a space geek and computer engineer, I applaud your most excellent presentation!
Hey Amy! So glad to see you back 😊 I’ve read most of Frank O’Brians book on the AGC and this is an awesome explanation of the triggers behind these alarms.
Your videos are awesome. Please keep making more of them. I grew up during the end of the Apollo days. Your videos bring back so many great memories.
I love this! I didn’t realize so much detailed and interesting information about this could be found. Thank you for your hard work presenting it to us!
The world today should remember the name Hal Laning. We continue to use his brilliant inventiveness and clarity to this day.
I spent six years working for NASA. I once had a vanity license plate which said HAL1202. I'm so proud people have come to recognize this guy for his foresight and intelligence.
Thank you Amy, well presented.
And welcome back.
Amazing video Amy!! Super interesting. Can't wait for your next book!!!!
Always making the most of what is available is key to success.
Great videos, glad you're back.
Great summary and explanation!
Thank you, as always, so very much.
Good work Amy. 50 anniversary coming up soon. I remember viewing the first walk back then. Thanks for the GREAT STORY and memories.
Love your amazing work! You are CRIMINALLY undersubscribed.
Great explanation of this key event in the history of the space program. Thanks amy.....
Thank you. Always informative and interesting.
Really well done, Amy. Incredibly informative.
Excellent breakdown of the complex processing sequence.
Great video as always thanks for all info you give us i love learning more every time i get one of your videos.
Great video, Amy! Best in-depth explanation I've heard of the 1201/2 issues!
Just watched this again!!! LOVE THIS VIDEO!!!
I must say - you are getting better and better in explaining with every new video. :)
Glad your back!
There were tens of thousands of unsung heroes of the Apollo program, the people who designed, built, and tested everything that was needed to get the astronauts there and back again. I'm proud to say that my Dad was one of them; he worked on the guidance system.
I really appreciate these informative videos!
Don't leave us again please. I love your documentary videos !!!
Interesting article. I had a basic knowledge of what happened but your nice video filled in enough of the blanks for it to make sense.
I vaguely remember an interview with Buzz Aldrin where he mentions the engineers designed it to use either the landing RADAR or rendezvous RADAR but not both at the same time (processing power being a valuable commodity). Buzz kept the rendezvous RADAR on during descent as a precaution in case they had to abort. Seems reasonable if he didn't know the system couldn't process fast enough to run both at the same time.
Ladco77 I'd say that could be a user interface issue today. If you should not use both, then make the user interface force you to have one or the other like a toggle switch.
But of course, back then, we had some lessons to learn, and stuff was designed in parallel. The UI team might have not known NOT to allow both ON as the software might not have existed when they finalized the UI... The bleeding edge of science!
Cool analysis
arstechnica.com/science/2015/07/no-a-checklist-error-did-not-almost-derail-the-first-moon-landing/
@@Bill_Woo Thanks so much, this is such a great link. I do recall an interview with Aldrin in which he said he kept the rendezvous radar on, but phrased as a casual "I thought it would be a good idea to have the rendezvous radar on just in case." I paraphrase, of course, but I think accurately, because it struck me as so significant at the time. Remember thinking he made it sound as if the idea occurred to him, did it as his own decision, wasn't an included item on the checklist - which seemed very odd. That interview may be the source of the erroneous idea a checklist error underlay the problem. Fascinating that throwing a switch at the wrong nanosecond could cause such a problem.
Thank you for these great videos!
Thank you so much for this Amy. I've read many stories and explanations around the '1201' and '1202' alarms, but none that covered it in the details you describe. I had no idea the systems of that time had any where near those capabilities of managing the programs.
If you are interested in "what you always wanted to know about the AGC but didn't know where to get the information from", I can recommend this talk
ua-cam.com/video/xx7Lfh5SKUQ/v-deo.html
Discussion of the software starts at 35:28
Glad you’re back, 😀.
Great video, as always.
Another awesome video Amy, nice!
Great presentation as usual especially your explanation of the event. Just on a side note my uncle was one of the engineers that worked on the guidance systems for the Apollo program. 👍
This is one of your best Amy!
This is interesting because I was just rereading Andrew Chaikin's A Man on the Moon. I just finished the part on the first moon landing so this video added a great deal to the story. Thank you. Great work as always Amy.
Good presentation. Its been awhile. Welcome back.
Glad to see this channel with fresh content ☺
You're the best and I miss seeing your face every month!! 💕
Thanks Amy..... I was really wondering when your latest vid would be published....it feels like a desert without your vids coming regularly.
So glad you are back! The gem of my day! 😃
A very clear and concise vid! Thanks for a job well done..
Always learning cool stuff on this channel.
And the logic behind it all has finally "clicked" for me! Great explanation!
Amazing work!
Great explanation. Thankx Amy.
You speak so well and present brilliantly. Great video.
Amazing thanks Amy
Fabulous video. Great presentation. You are terrific.
I learn so much for your channel...
Again awesome as usual
Wow, that is a great episode!
Great Amy well done.Another great video Bill
Very interesting and well made as ever!
Many thanks for the great video.
Brilliant design, thanks for the story.
Another excellent lesson in history. Thank you very much Amy. Also enjoy your "dry in, dry out" intro/outro formatics.
Amy... for you to explain, in detail, the causes and effects of the 1201 and 1202 alarms, which I have been reading about, but not fully understanding, since July 1969, and have those explanations crystal clear to me, a retired commercial pilot with a working, but not technical, knowledge of the flight director/autopilots I operated "back in the day", as well as my sooo-modern laptop, is a miracle of epic proportion. The people I have known in my life who have made the most lasting impressions on me have been the wonderful teachers I have had. One of them, my first flight instructor, is still a close friend, fifty years later. You are on this exclusive list of mine, and you have a wonderful talent for REALLY teaching, which is all too rare.
If this country ever institutes a roll of "Living National Treasures", as Japan has done for decades, you would be at the top of my list as a nominee.
Me ke aloha mai Hawai'i, Amy... 🌴😊🇺🇸
What's interesting to me is that in "Failure is not an option" Kranz notes that they trained on this exact problem in the simulator shortly before launch and therefore were prepared and ready during the mission. If they hadn't encountered it during sim they probably would have aborted the landing. I'd put a lot of credit in this case on the main who decided it was an important item to prepare the team for.
I just bought that book in the Johnson Space Center gift shop yesterday.
Thanks Amy love your videos.
Great video - thanks!
After a few minutes into your explanation I immediately thought of the 1201 & 1202 alarms.
A terrific episode, Amy! I love your work! Thank you for doing what you do.
You rock. AMY! Love your stuff
Another very interesting and informative video. You're awesome!!
The unsung heroes of NASA. So 😎 great info at a level every one can understand. Great vid.
Really well done!
I WAS LITERALLY ASKING MYSELF THIS IN THE THEATER!!! #PerfectTiming
Hi I'm clippy, I see you're having a guidance problem, can I help?
no clippy you never help!
M T - I think clippy got relegated to cryo tank stirrer on 13.
Clippy was attached to the 223rd copy of the redacted Mueller report.
an update is available at the microsoft store, would you like to download it? a small fee may be applied to your account.
Genius was my main man, poor young me actually thought it would work better than Clippy ;P
Thanks again Amy for another great video, I know you are looking forward to the 50th anniversary this summer as am I.
Excellent summary on the infamous 1201/2 alarms.! Love your work Amy. For those interested to delve deeper into this subject matter the best book to read is 'Digital Apollo' by MIT guy David A Mindell, very in-depth analysis on the story of the AGC.