Apollo Flight Computer from 1966 - Page 1
Forum section: electronics / projects

author: Homer J Simpson
author_rank: Super Contributor
timestamp: December 04, 2013, 06:38:01 pm
content: Found this on YouTube the other day. Sorry if it has already been posted.Pretty neat to watch especially half way through were the show testing and assembly.Not too bad for over 40 years ago.KT

author: dannyf
author_rank: Super Contributor
timestamp: December 05, 2013, 01:03:27 am
content: Your watch today probably has more computing power than that thing.

author: chrisc
author_rank: Unknown
timestamp: December 05, 2013, 01:43:39 am
content: Quote from: dannyf on December 05, 2013, 01:03:27 amProbably yes, but OTOH his watch will never get to land two men on the moon.Also good to keep in mind that those computers were constructed to be mostly immune to cosmic radiation, which has a habit of flipping bits and/or otherwise doing Bad ThingsTMto semiconductor circuits, so it's not quite an apples to apples comparison.

author: xrunner
author_rank: Super Contributor
timestamp: December 05, 2013, 01:51:54 am
content: Thanks for posting that!

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 05, 2013, 05:42:53 am
content: Quote from: chrisc on December 05, 2013, 01:43:39 amcomputing power is not all about landing a man on a moon. we can even make it without computing power. computing power aka automation is only for 2 kind of people (1) people that are too occupied with other things or to increase productivity (2) lazy people.

author: EEVblog
author_rank: Unknown
timestamp: December 05, 2013, 05:45:00 am
content: Quote from: Mechatrommer on December 05, 2013, 05:42:53 amNo, we can't land on the moon without computing power. Good luck trying!

author: Stonent
author_rank: Super Contributor
timestamp: December 05, 2013, 06:31:27 am
content: Quote from: EEVblog on December 05, 2013, 05:45:00 amYeah you can only fly halfway to the moon without it.

author: Rerouter
author_rank: Super Contributor
timestamp: December 05, 2013, 07:51:10 am
content: sure you can fly to the moon without computing power, just as long as you dont list landing with the passengers alive as a requirement,

author: BravoV
author_rank: Super Contributor
timestamp: December 05, 2013, 08:03:51 am
content: Quote from: Mechatrommer on December 05, 2013, 05:42:53 amWhats the name of thatpoor.... errrr ... brave Malaysian astronaut that Malaysia sent to the moon ?

author: grumpydoc
author_rank: Super Contributor
timestamp: December 05, 2013, 08:09:49 am
content: QuoteISTR Armstrong flew the landing "manually" because the site originally chosen was strewn with boulders.

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 05, 2013, 08:24:35 am
content: Quote from: EEVblog on December 05, 2013, 05:45:00 amwell well well (1) if only i got the "money" (2) i wont try in this lifetime since computing power is so cheap. at minimum all i need is a manual steering, fuel pedal and alot lot of gas and oxygen power, apart from other necessary items such as air tight pressurized chamber and fancy materials, purely "mechanical" including the control system, throw the electronics awaywell except maybe some simple sensors, laser distance guide or speedometer (not computing power which then from what i read in wiki is for UI only? i maybe wrong). though i cant claim to be able to navigate re-entry (only a "pilgrim" should be able to do that) but then since we talking about landing on the moon only not going back. but then, i believe the necessity of computing power back theniswas that, during the "space race", computing poweriswas already available, be it eeiswas not around, purely mechanical engineering alone is quite capable imho.Quote from: BravoV on December 05, 2013, 08:03:51 ammoon atmosphere is almost none existence so heat damage during the entry is quite not an issue. its not about bravery (or bravory?) its about knowledge and... wisdomi believe the late space shuttle Columbia had better computing power, but it was not the issue.edit: sorry "is" and "was" are the same in our native language we dont have past tense for "is" i can always srew up on that. "was" can be said as "is already" ohh my english.

author: Kjelt
author_rank: Super Contributor
timestamp: December 05, 2013, 08:43:07 am
content: Quote from: dannyf on December 05, 2013, 01:03:27 amWould be a hell of a watch that you point to two objects in the sky and it calculates your position, speed and acceleration.I would love a normal sized watch with a nice GPS , graphical retina display in a Jaeger Le-Coultre kind of design.

author: Alex
author_rank: Regular Contributor
timestamp: December 05, 2013, 09:38:54 am
content: Interesting to note how they refer to female workers as 'girls' and it sounds as if 'girls' is the model name for that machine. 14:30, 21:16, 21:21

author: dannyf
author_rank: Super Contributor
timestamp: December 05, 2013, 12:17:17 pm
content: QuoteI am not sure what laws of physics prevent us from landing on the moon without computing power. The (questionable) fact that we haven't done so doesn't by itself substantiate the assertion that we cannot.

author: EEVblog
author_rank: Unknown
timestamp: December 05, 2013, 12:52:53 pm
content: Quote from: grumpydoc on December 05, 2013, 08:09:49 amOnly thanks to the computational power required to get into orbit in the first place.

author: Wytnucls
author_rank: Super Contributor
timestamp: December 05, 2013, 01:04:19 pm
content: When Armstrong again looked outside, he saw that the computer's landing target was in a boulder-strewn area just north and east of a 300-meter (980 ft) diameter crater (later determined to be "West crater," named for its location in the western part of the originally planned landing ellipse). Armstrong tooksemi-automaticcontrol and, with Aldrin calling out altitude and velocity data, landed at 20:17:40 UTC on July 20 with about 25 seconds of fuel left.(Wikipedia source)

author: wkb
author_rank: Super Contributor
timestamp: December 05, 2013, 01:29:20 pm
content: Quote from: Kjelt on December 05, 2013, 08:43:07 amAnd it better run for >= 1 year on a small battery too..

author: grumpydoc
author_rank: Super Contributor
timestamp: December 05, 2013, 02:03:39 pm
content: Quote from: EEVblog on December 05, 2013, 12:52:53 pmAgreed.More from wikipedia -http://en.wikipedia.org/wiki/Apollo_Guidance_Computer. Actually the guidance computer seems pretty sophisticated, especially as it must have been designed in the early 60's.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 05, 2013, 02:19:26 pm
content: I too would like to see someone try to even get to lunar orbit without computing power. One less idiot who's never coming back.How are you going to do it? Point your ship in the general direction and fire the rockets?The moon isn't going to be in that place when you get there. It's going to be a looooong way away.How are you going to know when to shut off the initial burn? Good luck even approximately matching velocity, if by some incredible fluke you managed to pass anywhere near the thing.If by _two_ miraculous flukes you managed to intersect the lunar orbital trajectory you wanted, with roughly the right velocity for that orbit, how are you going to adjust your velocity at exactly the right time and amount, to achieve a nice relatively constant altitude orbit? Rather than (say) one which intersects the surface a third of the way round. For an orbit 110 Km up, around a body that is 3,474 Km diameter, that's rather precise.Even if I had some kind of anti-gravity drive, with unlimited power source, I'd still rather not try space navigation without a lot of computing power and software able to do orbital simulations, inertial navigation, position fixing from star charts and some damned good laser and radar ranging. Because a lot of the precision of the lunar mission guidance came from Earth ground tracking. Without which they'd have been much less likely to succeed.

author: BravoV
author_rank: Super Contributor
timestamp: December 05, 2013, 02:38:25 pm
content: Quote from: TerraHertz on December 05, 2013, 02:19:26 pm+1Like

author: VintageTekFan
author_rank: Regular Contributor
timestamp: December 05, 2013, 03:36:30 pm
content: I feel like I missed my introduction into electronics by about 50 years.

author: SeanB
author_rank: Super Contributor
timestamp: December 05, 2013, 08:50:12 pm
content: You do not need an electronic computer. You can precalculate most of the info using simple Newtonion mechanics and do so on paper using your brain and a reasonably competent Mathematics major. Then you just follow the plan, and have some simple instrumentation to give you absolute attitude, velocity ( integrated from acceleration) and an accurate time measure to do the burns needed for a low fuel consumption approach. Computer there is a person doing work on paper with a pencil, hopefully with a second and third person to check the results. Digital computer was there to make work of landing and calculating times easier, by having a simple integration of fuel used to calculate remaining hover time and to do the predetermined burns needed with good accuracy and with the right orientation.

author: Stonent
author_rank: Super Contributor
timestamp: December 05, 2013, 08:58:02 pm
content: I think they also had log tables and other books with them that had various scenarios precalculated in the event of a system failure they had some slight chance of surviving a bad scenario.

author: BBQ
author_rank: Regular Contributor
timestamp: December 05, 2013, 09:30:21 pm
content: Who needs computers and IMU:s when you have the right tongue angle?http://en.wikipedia.org/wiki/Lunar_Escape_Systems#Guidance

author: Paul Moir
author_rank: Frequent Contributor
timestamp: December 05, 2013, 10:04:28 pm
content: There was also the abort guidance computer to back it up:http://en.wikipedia.org/wiki/Apollo_Abort_Guidance_SystemBut the most interesting thing about the thing to me is that it could be restarted at any point and pick up where it left off with no real interruption. While the software was pretty interesting, the hindsight report is pretty dim on it's development:http://history.nasa.gov/computers/Ch2-6.htmlI didn't know about the lunar escape system. That's pretty funny! Talk about flying by the seat of your pants...

author: Noize
author_rank: Regular Contributor
timestamp: December 05, 2013, 10:20:00 pm
content: Quote from: SeanB on December 05, 2013, 08:50:12 pmThe Apollo computer software had anExtended Kalman Filterin it. Imagine trying a do that on paper, you would have to characterise the sensers, the atitude control and propulsion and at the right time!Yes you could fire a missile ballistically at the moon by working it out on paper but we are talking about the Apollo mission. And on the Apollo 13 mission yes they did fire the rockets manually to a minor correction(edit-I can't remember of the top of my head if they use the onboard computer calc the corrrections) to the course for Earth re-entry, but imagine trying to calculate as you are orbiting the Earth, on paper, when and how to do the trans-lunar injection maneuver to have free return trajectory as Apollo 13 did. If you can do that you can rightfully say "ThatVon Neumann Geezercan't add up for shit. YeahEulerandRamanujanthey are just shoe shine boys compared to me, Doctor Spock you can fuck off as well!"

author: Noize
author_rank: Regular Contributor
timestamp: December 05, 2013, 10:21:55 pm
content: Oh yeah have you ever played asteroids, yeah exactly.

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 05, 2013, 11:50:11 pm
content: Quote from: TerraHertz on December 05, 2013, 02:19:26 pmohhh the people intended to go up there are so stupid of "not knowing" that? no need prelaunch physics class etc and blind bravery just hit the trigger? one fundamental flaw that people forgot "what creature" programmed the computing power, the source of its knowledge and most importantly is "its limitation".Quote from: Noize on December 05, 2013, 10:21:55 pmno amount of computing power to date? (and sensories of course! dont forget) that can evades asteroids, its only in hollywood movies (even in hollywood they failed to evades asteroids).Quote from: Noize on December 05, 2013, 10:20:00 pmand what is kalman filter and its purpose? maybe you can shed some light since i coded the simplest approximate version (flawed maybe) in arm based device. will someone dead without it? as i said, computing power is just for better productivity (or faster calculation to assist human they all similar meaning to me), but the decision to land a man on the moon is not just that. i believe its more appropriate to say... without "good algorithm or software" we cant land on the moon (even with my 4 cored GHz cpu), but then again, i believe software is not all about that.

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 09:48:49 am
content: Quote from: Wytnucls on December 05, 2013, 01:04:19 pmThis is more or less correct.The way that the LEM computer worked was that it was always in control of the landing. Armstrong used the translation control to designate a down-range landing by "clicking" it in increments, moving the target landing site downrange. There was never a "manual" control of the kind you'd ordinarily think one to be.In fact, the machine was so unstable in flight in a gravitational well that if it weren't for the computer controlling the thrusters the LEM would have embedded itself in the lunar regolith in a hurry. When it was in free flight in orbit it was much easier to control according to the men who flew them.Anyone who thinks that they can design a craft that would be stable enough under human control just doesn't understand the physics involved. Reaction times for a human arefartoo slow. Never happen. Not even Alan Sheppard had the guts to try something like that.

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 10:16:58 am
content: Quote from: SeanB on December 05, 2013, 08:50:12 pmI guarantee you that you not only need one, your life depends on it.QuoteI defy you to do that in real time. Arthur Benjamin would have a tough time with that, and he's about the most impressive human calculating machine I've ever seen.No, without a machine to react quickly enough to stabilize the craft, you're ditched. There's simply no way for a human with reaction times averaging nearly one second (or more) to be able to do that. You'd need to be able to react in tens of milliseconds to be able to manage it, and there's no way you could take in the information required and react that fast without some significant electronic and mechanical assistance. The guys at MIT worked relentlessly to get it right, and it's a good thing they did.I said (in another reply) that Alan Sheppard didn't have the guts -- what I should have said was that he knew better.

author: grumpydoc
author_rank: Super Contributor
timestamp: December 06, 2013, 10:47:29 am
content: QuoteAh, that is interesting - I always got the impression that itwasmore manual than that.

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 10:58:07 am
content: Many people have that misunderstanding. The controls only told the computer to change the target; the computer flew the machine.

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 11:22:39 am
content: This ought to clear up any confusion. Dave Scott, Apollo 15 Commander, in his own words. Grab it fromhttp://forum1.valleyinfosys.com/Downloads/agc_scott.pdf.

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 11:25:21 am
content: Also have this (a bit bigger -- 177MB)http://forum1.valleyinfosys.com/Downloads/A15Delco.pdfEdit: I even have the schematics for the AGC if you're so inclined.

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 12:00:11 pm
content: Damn that Google bot is fast!Took it 16 minutes to find this thread and download those from our site...

author: dannyf
author_rank: Super Contributor
timestamp: December 06, 2013, 12:04:08 pm
content: QuoteWhat kind of physics does one need to understand to come to that conclusion?

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 12:06:39 pm
content: Newtonian mechanics ought to do it.

author: dannyf
author_rank: Super Contributor
timestamp: December 06, 2013, 12:13:30 pm
content: Which part of Newtonian mechanics would suggest that a human cannot do it?

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 12:20:38 pm
content: Well, for a start, take a top-heavy machine built with a skin of barely-there thin aluminium (that if you were standing inside it while it was on the factory floor and dropped a wrench you'd be picking up from underneath the machine.)Then take a look at the moments of inertia generated by the decent engine, thrusters (sitting out on lever arms to get snappier control) and figure that in... you'll need to count the weight of the machine, its mass distribution, center of mass and the roughly 1/6g at the moon.The lack of any aerodynamic drag, and a set of somewhat slippery pads that it landed on (which slid a couple of times on landings) giving you some frictional coefficients to deal with that might be a bit unfamiliar, again because of the environment.There's more, but we'll leave it there. Then hand all of that to a man who'd never been there either, and you have a recipe for a challenge that took better minds than ours to solve.

author: dannyf
author_rank: Super Contributor
timestamp: December 06, 2013, 12:30:23 pm
content: QuoteThat sounds like a convincing argument for it being a difficult task, not an impossible task - from the point of view being against Newtonian physics.QuoteYeah. But before humans flew, no human had ever flew; before humans went to the moon, no human had ever gone to the moon; ...If the mere fact that we haven't done anything is a sound argument that we can never do that thing, we would still be living in caves.QuoteChallenge? Yes.Impossibility? No.

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 12:33:56 pm
content: Impossibility -- yes. You can't ignore the physics of the physical human.You can't react fast enough to control that mass in that environment with a machine generating the moments of inertia that the LEM did. I promise you this is true, because it's a dynamic system in which all of those factors change every second. The calculus you need to manage that makes it impossible for a human, never mind the fact that no human could react that fast, and never mind that the human in question had zero time to adapt to the circumstance.I'm sorry, but there's absolutely no chance that it could have been done.

author: Christe4nM
author_rank: Unknown
timestamp: December 06, 2013, 12:53:47 pm
content: It's amazing to see how far we've come in computing technology. I was watching the wiring process with my mouth literally open wide while keeping in mind that it was cutting edge technology at that time. My respect for those engineers has only gotten greater.

author: ovnr
author_rank: Frequent Contributor
timestamp: December 06, 2013, 01:34:09 pm
content: To the nutcases that think it's possible to land on - and return - from the moon without any computational aid, why don't you go download Kerbal Space Program and have a go at doing exactly that. Oh, and remember to not use any of the navigational aids apart from the acceleration and rotation vectors; the rest require, you know, computation.

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 06, 2013, 02:24:05 pm
content: and what good it is if i can but still i cant prove it to you? and who's going to pay my training time?granted thrusters need stabilizer or somesort of feedback control system, but i prefer not to term it as "computing power" to land on the moon, which is much more like "unmanned space program". if you have "enough money" to pay, i can design one fully manual control rocket, thrusters stable enough to control by a joystick, just dont expect it to complete by tomorrow and... given that you have "enough money" as required"computing power" as in "automatic navigation" is mostly about "good economics" or "minimal resources" used. landing on the moon has much to do with human factors, economics and politics i guess. but if you prefer to prove me wrong? just provide the money i want, i believe not even America and Russia combined are willing to payyou know "brute force" method is sometime not accepted as "proper method"

author: larry42
author_rank: Regular Contributor
timestamp: December 06, 2013, 04:25:59 pm
content: Quote from: walshms on December 06, 2013, 12:33:56 pmI'll just add my engineering cents to this discussion.I don't know the flight characterstics of the lander etc. If a lunar landing module was built that was aerodynamically stable then I see no reason that it could not be controlled by a skilled human. How do you train the human - I agree that that's a hard thing to do without appropriate (computer controlled) simulators.In order to have certain advantages, modern military jets are not designed to be stable - but there is no doubt that humans were able to fly planes at great speeds even before the computer controlled avionics.The navigation part is, IMO perfectly solvable with classical physics and therefore can be calculated, nomographs made, custom slide-rules etc - people have been navigating across huge stretches of ocean for many centuries.

author: Wytnucls
author_rank: Super Contributor
timestamp: December 06, 2013, 05:13:31 pm
content: Aerodynamically stable? Aerodynamics are useless on the moon. That's why the lander could look like a cement mixer and still be 100% functional.The contraption was totally unstable, sitting on top of a rocket engine. It needed computers to stabilize it during the descent through the use of auxiliary pulsed jets, gyros and accelerometers.It also needed computers to follow an economical trajectory to a preplanned safe landing area, as fuel conservation was critical.The machine could be controlled 'manually' starting from a height of 2000 feet, but only through instructions to the flight computers.Astronauts actually practiced flying the LEM on a Grumman rig, but they managed to crash it on three occasions, only to be saved by their ejection seats.

author: chrisc
author_rank: Unknown
timestamp: December 06, 2013, 05:21:21 pm
content: Quote from: ovnr on December 06, 2013, 01:34:09 pmI second that. Additionally I would like to recommend Lunar Flight (http://www.shovsoft.com/lunarflight/). It's way harder than it looks to just move a few hundred meters and set down safely without running out of fuel. I bought it mainly to check out the Oculus Rift integration (which, BTW, is very well done - the sense of immersion is fantastic) and actually don't play it much apart from that because itisso hard!(BTW the author is an Aussie and the program is only ten bucks).

author: Sigmoid
author_rank: Frequent Contributor
timestamp: December 06, 2013, 05:56:15 pm
content: There are two reasons space flight needs some kind of computer (either a digital, electronic one, or an analog one... andeven an inertial autopilot can be considered an analog computer).One is that space flight is kind of hard on human physiology. It's one thing that you can theoretically take a rocket into orbit manually in a simulator (even though it is notoriously hard... the FlightGear simulator has a pretty accurate rocket simulation of a soviet spaceship, and being able to reach orbit on manual control is considered a hardcore achievement in the community), but doing the same with 10Gs pressing down on you, and your inner ear giving you hell isn't exactly the same experience.The other is that at high speeds and large distances, even small errors can be fatal, and constant feedback and correction (the way a human normally flies an aircraft) is prohibitively expensive in terms of fuel, and unintuitive to boot.

author: dannyf
author_rank: Super Contributor
timestamp: December 06, 2013, 05:57:13 pm
content: QuoteOK. Which part of the physics would help you substantiate that claim?QuoteOK, then how fast do you need to react to control the mass in that environment? how fast do you think a human can react?QuoteThank you for your promise. It is very assuring, I am sure.To give you an example, a bicycle is a dynamic system in which all of those factors (quite a few of them actually) change every second or faster. Other than a few really challenged people, most humans have no problem controlling it, your assurance aside.QuoteOK, what "calculus" exactly are we talking about? Why is that impossible for a human? ...QuoteWe know that already. Repeating a claim doesn't make that claim any more credible.We needs facts, numbers, science, math, etc. to help sustain the conversations at a more substantive level.

author: dannyf
author_rank: Super Contributor
timestamp: December 06, 2013, 06:03:48 pm
content: QuoteSo is a bicycle, which physically is the same as a launching rocket.Not many of us need a computer to rid it,and there are count-less examples like that.Again, you guys made a convincing case that it is difficult for a human to do. I would encourage you to make a better case of why it is impossible, based on facts, science and math, etc.Repeating assertions doesn't count.

author: Wytnucls
author_rank: Super Contributor
timestamp: December 06, 2013, 06:16:23 pm
content: Being obtuse doesn't help. Research instability before comparing a bicycle to a rocket.Computers on a moderately unstable F-16 jet make 2000 computations every second to keep it going where it is supposed to. If the computer fails, the pilot ejects.

author: dannyf
author_rank: Super Contributor
timestamp: December 06, 2013, 06:24:19 pm
content: QuoteWrite out a mathematical equation (or equations) about a launching rocket and I will write the same set of equations about a bicycle to prove that mathematically they are identical.QuoteI would make it easier for you: you can easily have 100 computers on a F-16 fail, yet the pilot can finish his missions and land safely.Unable to be specific doesn't help you.

author: Noize
author_rank: Regular Contributor
timestamp: December 06, 2013, 06:51:59 pm
content: Quote from: walshms on December 06, 2013, 11:25:21 amI am interested in seeing the schematics of the AGCPage 401 onwards of the large document you provided a link to has information about the Kalman filter used in the computer.

author: macboy
author_rank: Super Contributor
timestamp: December 06, 2013, 07:07:37 pm
content: Methinks dannyf is trolling. You will not end this argument with logic or fact. I don't recommend continuing.But any discussion of the Apollo flight systems might be interesting...Consider that completed memory module that was roughly the size of a pound of butter. It held 64 kbit of information. I microSD memory card the size of your fingernail can hold at least 256 Gbit (32 GB), several million times as much information.

author: dannyf
author_rank: Super Contributor
timestamp: December 06, 2013, 07:21:24 pm
content: QuoteIf we cannot build our arguments on logic or fact, what do you think we should use instead? rumors or faith?I didn't want to mention this in the middle of our love for needing a computer to fly a rocket (because it is unstable), think about all the non-computer piloted rockets we have fired,

author: Noize
author_rank: Regular Contributor
timestamp: December 06, 2013, 08:45:12 pm
content: Quote from: dannyf on December 06, 2013, 07:21:24 pmGive some examples, I can't think of any.

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 08:56:46 pm
content: Quote from: larry42 on December 06, 2013, 04:25:59 pmMaybe you shouldn't have.

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 09:08:03 pm
content: Quote from: dannyf on December 06, 2013, 05:57:13 pmNo, you need to be difficult and press your point no matter how deeply you dig yourself in.I might actually know something about this. That might be worth considering.To answer the questions worthy of an answer here: you will want to learn something about the biology of nerve conduction and the propagation speed of nerve impulses in the brain and body, and compare that to the propagation of electrons in copper wire. While you're at it, spend a little bit of time on the mechanics of the way that we humans balance, detect movement and correct balance while doing ordinary activities, and compare that with mechanical inertial systems designs used in Apollo.Finally, if the mass, center of mass or moments of inertia of your bicycle change every second, I suggest you need a new bicycle. The LEM used fuel to land, and using it means expelling that mass, changing those coefficients continuously. Let's see how quickly you can calculate that, or for that matter, any human can calculate that.By all means, come back and tell us how you've done.

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 09:10:49 pm
content: Quote from: Noize on December 06, 2013, 06:51:59 pmhttp://forum1.valleyinfosys.com/Downloads/agc_schematics.zipEnjoy.

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 09:13:02 pm
content: Quote from: macboy on December 06, 2013, 07:07:37 pmMethinks you are correct, sir, and I will leave it there.

author: dannyf
author_rank: Super Contributor
timestamp: December 06, 2013, 09:20:46 pm
content: QuoteI just gave you two: bicycles and (dumb) rockets.Boats (propellers in the back), rwd cars, jets (in the back), motor-cycles (rwd naturally), etc. are all examples of inherently unstable vehicles that require no computers to pilot.The whole argument reflects a sub-culture in our society where people hide behind fancy terms ("physics", "aerodynamics", "newtonian laws", "computers", to name a few) when in fact they don't even have the basic math skills / science to have a well reasoned conversation - you pushed them a step or two deeper, you have exhausted their "vast" knowledge base.

author: senso
author_rank: Frequent Contributor
timestamp: December 06, 2013, 09:28:07 pm
content: Bycicles have a pair of very nice gyroscopes that want to keep their attitude, grab a bycicle, give 3 steps and launch it, surely the bike will travel more than 10m before it is going to slow to be kept stable by the wheels.A motorcycle is a bit more challenging, there is a clutch(usually), I started riding motorcycles with 13 years old, its not hard at all.Now, could you keep a rocket stable while it blasted at thousands of km per hour through the atmosphere(this might be possible), but can you insert said rocket in a orbit without a computer?I don't know if the V2 rockets had computers, but they must used some sort of contraptions to connect gyros to the direction controls.Probably some sort of computer was involved in the loop.

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 09:34:35 pm
content: Quote from: senso on December 06, 2013, 09:28:07 pmAngular momentum. It's an experiment conducted at nearly all science museums in the US. Take a bicycle wheel, put handles on the axle, spin it and then try to deflect it through an angle while sitting on a seat that can freely turn. When you do that, you and the seat start precessing.QuoteIn the V2 it was purely mechanical, but you have the right idea. It used an inertial platform that altered the thrust vector.

author: Noize
author_rank: Regular Contributor
timestamp: December 06, 2013, 09:40:53 pm
content: Quote from: dannyf on December 06, 2013, 09:20:46 pmYou couldn't give any examples of non computer controlled piloted rockets

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 09:43:52 pm
content: Quote from: Noize on December 06, 2013, 09:40:53 pmNo person (of sound mind) would strap themselves into any rocket that didn't have a computer controlling it.

author: dannyf
author_rank: Super Contributor
timestamp: December 06, 2013, 11:14:37 pm
content: QuoteThe gyro-effect from a spinning wheel in a bicycle is so much smaller, particularly when a fat guy is peddling it at low speed.Mathematically, the bike is identical to a launching rocket in that the center of gravity is higher than the lift - the rocket vs. the ground. So both are inherently unstable. The same with a boat: the resistance from the water (=gravitational force on a rocket) is a head of the propulsion (=the thrust from the rocket). Or the same from a rwd car....All it takes is one's ability to reduce them to a math/physics problem to see their equivalency.

author: walshms
author_rank: Regular Contributor
timestamp: December 06, 2013, 11:21:24 pm
content: Quote from: dannyf on December 06, 2013, 11:14:37 pmThat clearly excludes you.You just equated drag with gravitation and confused thrust from a rocket (which has nothing but its thrust vector to stabilize it) with a rear-wheel drive vehicle (with four contact patches from tires on the ground that stabilize it quite nicely.)When you feel you've displayed enough ignorance you'll stop. In the mean time, I'm going to sit back and watch you make a complete fool of yourself. This is becoming entertaining now.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 07, 2013, 12:10:09 am
content: Here's a simple analogy.Can you balance a stick, standing upright on your finger?The length of stick you can balance is proportional to your reaction time. The shorter the stick, the faster your senses, judgment and motions need to be. I can no longer balance a foot-long ruler, but I used to be able to.The LEM's mass, sitting on top of a rocket engine that could fully support that mass in the Moon's 1/6th G, is very like a stick standing on your finger. Except worse, because the rocket thrust provided no inherent fixed point the LEM 'stood' on. Plus probably had some thrust vector 'noise', being you know, a big chemical flame.I'm guessing that trying to keep the LEM upright at all, let alone in controlled descent while maximizing fuel efficiency as if your life depended on it (because it did) would be a bit like trying to balance a one inch long, needle-pointed stick, in the middle of a cat fight.I'll take the computer assistance, thanks.Oh and btw. Who else remembers the original Atari vector graphics arcade game Lunar Lander?It was simple. You started at a fixed height, with a set amount of fuel. The 'LEM' was fixed upright. The only control was a variable throttle for the main rocket engine. The objective was to touch down with a survivable vertical velocity.This meant optimizing the descent velocity/time graph, to get down before you ran out of fuel, but with enough fuel left in the final moments to nearly zero your fall rate.It was _extremely_ hard to do. I could very rarely land.The problem was the usual one with any kind of space navigation. Right from the beginning of your journey you have only an extremely narrow manifold of position & velocity that you must stay within or you are doomed to fail. Go outside it, and you will not have the thrust resources required to correct the accumulated errors later on. But your human senses can't see that manifold. And even if you could, your reaction times are not good enough, by a large margin.The Atari Lunar Lander game was only possible to win (sometimes) because it was a vastly simplified and shortened task, compared to the real thing. Also you could see yourself (LEM), your relative descent rate and the surface all in one screen. That's not going to happen in space navigation.

author: walshms
author_rank: Regular Contributor
timestamp: December 07, 2013, 12:32:59 am
content: Quote from: TerraHertz on December 07, 2013, 12:10:09 amExactly right. If they were off by just 1 meter per second on a mid-course correction, they'd have missed the moon by more than 192,000 kilometers if they didn't fix that. (They always had several mid-course corrections for just that reason.) Typically, they'd be looking at residual velocities in the range of 3 to 10 centimeters per second, and there's no way they could have done it without the AGC.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 07, 2013, 12:51:16 am
content: Holy f*ck.I finally had time to watch the videoThe AGC backplane was wirewrapped!Also I notice the wraps had 2 turns of still-insulated wire, then the bare wrap. Yes it was called the 'modified wrap', but it was the right way to do it if you wanted the damned thing to keep working.

author: walshms
author_rank: Regular Contributor
timestamp: December 07, 2013, 01:04:51 am
content: Quote from: TerraHertz on December 07, 2013, 12:51:16 amAmazing, right? The roughest part of the entire mission was the dynamic loads on launch (the astronauts described it as being a pretty wild ride) and staging. Once they got into Earth orbit, it wasn't going to experience those kinds of loads again, and only had to survive the mission. As long as they got enough turns on the wire, it wasn't going to fail; using a machine to do the wrapping ensured that.

author: dannyf
author_rank: Super Contributor
timestamp: December 07, 2013, 02:12:20 am
content: QuoteI hear your pain.Basic abstract thinking, in math or physics, can be challenging for some of us. However, I am confident that as you mature, you will be able to start to understand it a little bit more.Don't give up.

author: dannyf
author_rank: Super Contributor
timestamp: December 07, 2013, 02:16:41 am
content: QuoteYeah. That's basically it.The lander has the advantage of having thrusters on the side to help it maintain balance.QuoteThen there is the question of what is a "computer"? A negative feedback circuitry, for example, can be viewed as an analog computer too.If that doesn't meet your definition, how about a pid controller?...

author: TerraHertz
author_rank: Super Contributor
timestamp: December 07, 2013, 02:32:08 am
content: Quote from: dannyf on December 07, 2013, 02:16:41 amI don't care what form the calculating system takes. Analog pneumatic, for all I care.By "I'll take the computer, thanks" I mean I couldn't fly it by directly controlling the various thrusters, main engine gimbals, etc. Any system in which the controls are abstracted, and the pilot indicates what craft movement/position he wants to achieve, and the system does whatever balancing/thrusting actions are required to achieve that (with much finer & faster responsiveness to instabilities than a human could achieve) is 'computing' in my book.I too think you are borderline trolling.

author: dannyf
author_rank: Super Contributor
timestamp: December 07, 2013, 03:11:38 am
content: QuoteThat's a very broad definition of "computing" in my view. For example, it would include any form of negative feedback, including the ground effect of a blasting engine near the surface in an otherwise open-loop system.

author: Rick Law
author_rank: Super Contributor
timestamp: December 07, 2013, 03:37:33 am
content: Quote from: EEVblog on December 05, 2013, 12:52:53 pm(EDITED - first save missed a line...)Actually, it depends on what you mean by "computational power" and "getting into orbit". During WWII when rocket science was first developed to a point to reach our stratosphere: Plenty of computation power were used: analog computing, electro-mechanical computing, analog computing and people power. In the US, our computers were girls who did all the computations. Their job titles were "computers". Typical computer centers are near (and at least in one case: on) female college campus. The Philadelphia PA center was in fact on campus at an all girl's college. Non-human powered computation were mostly electro-mechanical or analog.Von Braun would have made it into orbit had he focus on reach instead of tonnage of explosive payload. His rockets would have been able to go into orbit had he tried (would have, given more work). All with with non-electronic computing. It is hard to argue that (USA's) early rockets and even Mercury space rockets were more or less modified V2's or later generation V2's.By the time we landed on the moon, the amount of computation done digitally (measured in say total bytes processed, or FLOP*time, or MIPS*time) is less than what a typical smart phone would have done in a day today.The lovely looking girl-computers would have easily handled all the necessary computing to get us into orbit and land on the moon in my view.Now it also depends on what you mean by "getting into orbit". Getting into orbit itself is easy. Getting into stable orbit is the hard part. Throw a rock hard enough, you can get it into orbit. No computation necessary.

author: Noize
author_rank: Regular Contributor
timestamp: December 07, 2013, 04:03:15 am
content: We are not talking about getting into orbit, you can do that balistically. We are talking getting man on the moon and back again.It is said that fighter pilots(humans) are good at differentiation but awful at integration. We are not talking about maths on paper but judging through the physical senses. I heard that from some professor that develops the flight training program for the RAF on a documentary. This isn't Battle Star Galactica where you have unlimited fuel, then you could fly to moon with no guidance and land.

author: Noize
author_rank: Regular Contributor
timestamp: December 07, 2013, 04:07:00 am
content: Apt

author: walshms
author_rank: Regular Contributor
timestamp: December 07, 2013, 04:08:30 am
content: Nice one!

author: Wytnucls
author_rank: Super Contributor
timestamp: December 07, 2013, 05:26:13 am
content: If anybody has a solution to fly to the moon and back without computers, please contact the Indian Space agency. They are planning a manned mission by 2020. Tell them they don't need silly onboard computational power or computerized control systems. It is all very simple, just like riding a bicycle, anybody can do it and you have the equations to prove it.They may even offer you a job as their first astronaut.

author: walshms
author_rank: Regular Contributor
timestamp: December 07, 2013, 05:47:13 am
content: There may be no way to convince some people that they know less than they think they do; nonetheless, I've always tried to open closed minds. If there's a fault in that, I accept that as being mine.Unfortunately, it seems even the facts -- independently verifiable -- won't be enough. I'm certain that if I'd gone through the math, spelling it out for him, he'd still find reason to challenge it. I'm not here to do his homework, and he'll never learn anything if he thinks he knows everything.Reminds me of one of my favorite quotes:"It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt."- Mark Twain

author: walshms
author_rank: Regular Contributor
timestamp: December 07, 2013, 05:58:03 am
content: Quote from: Rick Law on December 07, 2013, 03:37:33 amVon Braun's rocketsdidgo into orbit. He was a central figure in the programs at NASA, working for the Army Ballistic Missile Agency at Redstone, and managed to salvage the whole Explorer satellite program when the Vanguard failed spectacularly.It was Von Braun's team that designed Apollo Saturn.People forget that while he had Nazi affiliation, he surrendered to the US to get the weapons he designed away from the Nazis. He didn't care for war, or about an ideology -- he only cared about his rockets.

author: walshms
author_rank: Regular Contributor
timestamp: December 07, 2013, 06:08:51 am
content: Werner Von Braun, second from the left with the binoculars) at the launch of Apollo 11; he was the deputy associate administrator for manned spaceflight at NASA HQ at that time.

author: Crazy Ape
author_rank: Regular Contributor
timestamp: December 07, 2013, 06:38:00 am
content: Quote from: walshms on December 07, 2013, 06:08:51 amCount again. Just because the old guy and his mate are working out how to karate chop a telephone cord, doesn't mean they aren't there.I wonder what funny captions one could overlay on the pic, it's begging for it.

author: walshms
author_rank: Regular Contributor
timestamp: December 07, 2013, 06:43:56 am
content: Oh sure, fault me for talking about the subjects of the photo...How about "Told you he'd look funny in that dress! That's what he gets for betting against us..."

author: marshallh
author_rank: Unknown
timestamp: December 07, 2013, 06:46:41 am
content: Is that Chris Kraft first on the left with the headset?

author: Crazy Ape
author_rank: Regular Contributor
timestamp: December 07, 2013, 06:56:44 am
content: Quote from: marshallh on December 07, 2013, 06:46:41 amI don't know, I've tried looking for a key / description. But, those two at the end remain invisible it seems.http://www.flickr.com/photos/nasacommons/4940991666/#

author: walshms
author_rank: Regular Contributor
timestamp: December 07, 2013, 07:04:52 am
content: no... Chris was in Houston.

author: walshms
author_rank: Regular Contributor
timestamp: December 07, 2013, 07:26:38 am
content: Quote from: Crazy Ape on December 07, 2013, 06:56:44 amCharles W. Mathews, Werner von Braun, George Mueller, and Lt. Gen. Samuel C. Phillips

author: Crazy Ape
author_rank: Regular Contributor
timestamp: December 07, 2013, 08:58:45 am
content: Quote from: walshms on December 07, 2013, 07:26:38 amYep, I can read that in the link.There are four other people in that image. The invisibles.

author: Phroon
author_rank: Contributor
timestamp: December 07, 2013, 10:41:00 am
content: I found someone who built an emulator for the Apollo Guidance Computer, on which you can run the original code that flew on the Apollo missions (albeit in core memory form).Check it out. They have windows, mac and linux binaries available for download.

author: BillyD
author_rank: Regular Contributor
timestamp: December 07, 2013, 10:57:55 am
content: Quote from: dannyf on December 07, 2013, 02:12:20 amhttp://search.dilbert.com/comic/Understand%20Easy

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 07, 2013, 11:34:15 am
content: ok i see the misunderstanding or someone tried to redefined something that is very well not accepted. there is a discussion about feedback controlled PSU around here a while back. an arduino or mcu (computing power) based feedback control and everybody just rampant its nuts, we need an "analog" feedback control you fool! so they said. now, can an opamp be considered as "computing power"? can some config of gyros, hydraulic piping, springs etc can be considered as "computing power"? or even... they said a human is a "computing power"? if a human is computing power, then yes, not just land on the moon, but its impossible to have lifeform on earth without "computing power", i'll surrender its just up to your definition of what "computing power" is. for me, some configuration of mechanical devices or analog circuits that is meant to control something is not "computing power", computer for me is to compute something, granted it can be built mechanically as proven by charles babange, but its specific purpose is to "compute", to assist human in computation.my point was, "control feedback" for thrusters or anything that unstable can be made without "computing power", its just it will not be economical during the day, one of biggest problem with this kind of project is funding (money or economy), and the cost of "less than watch" Apollo computer (the few ICs and PCBs?) is just a small portion of it i believe. granted without it, the cost will turn exponential (because the cost is highly related to the rocket weight), but not impossible, the impossible is the money because one reason is every country want to keep the money to themselvesif it still is today, ISS will be "impossible". but no, the ISS is not, the money is.and from what i read, designing a rocket is not like designing a bicycle. the most difficult part in "rocket science" is the thruster itself including the stability of burning gas and the mixing. there must be a feedback control for it. and the thrust force to escape gravity is so vast that slight offset or mistake from centre of gravity will turn the rocket turtle 10x before exploding, that also need feedback control if we want to go straight up. well, its the "feedback control" the "computing power" if you want to say so. it was not my definition.

author: dannyf
author_rank: Super Contributor
timestamp: December 07, 2013, 12:56:12 pm
content: QuoteFor the less informed, google the history of opamp, particularly in reference to "analog computers".QuoteThat would be a fairly narrow-minded definition of "computers". It does highlight the importance of understanding our (different) basis of conversations.But hi, you certainly have the right to do that.

author: dannyf
author_rank: Super Contributor
timestamp: December 07, 2013, 01:01:57 pm
content: QuoteFlight simulation isn't that difficult, particularly for today's computers. A tremendous amount of complication comes in due to vehicle dynamics. You can probably get the code running in the original computer; you can write your own program to run on that; However, if your vehicle model is wrong, your simulation wouldn't be meaningful at all.

author: VintageTekFan
author_rank: Regular Contributor
timestamp: December 07, 2013, 02:56:21 pm
content: Interesting forum link to a homebrew analog computer (with pictures!):Link

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 07, 2013, 05:58:29 pm
content: Quote from: dannyf on December 07, 2013, 12:56:12 pmdid you mean...http://www.dummies.com/how-to/content/electronics-components-how-the-op-amp-came-to-be.navId-810969.htmlbetween... (1)feedback loop(2) opamp and (3) analog pc, which one comes first? chicken or egg? knowledge evolves. the name "opamp" came to be when analog pc is invented, but the concept of an opamp (feedback loop) is already there far far earlier back to medieval age. edit: and to avoid further confusing or trolling. we are not talking "analog pc" we are not talking opamp as an adder or multiplier, we are talking opamp as a stabilizer, a simple negative feedback.

author: Noize
author_rank: Regular Contributor
timestamp: December 07, 2013, 07:18:35 pm
content: I have all the editions from my dad of the "journal of the interplanetary society" from 1957 to mid sixties. Lots of good papers on orbital mechanics, communications etc.... Alot of the authors went onto work for NASA. I havent got a scanner but a 13 megapixel camera in my phone. But amongst other excellent stuff their is a account from Hermam Oberth and Von Braun of literally just like a hackerspace they formed an amateur rocketry group because they were interested in space exploration. From what I remember one of the books that inspired them was from this guyKonstantin Tsiolkovsky. Had to google Father of russian rocketry to, f**k that remembering that after these years. But he was the first to propose going into outer space using multi-stage rockets in around the years 1905ish

author: geo_leeman
author_rank: Regular Contributor
timestamp: December 07, 2013, 07:28:54 pm
content: "Digital Apollo" (http://www.amazon.com/Digital-Apollo-Human-Machine-Spaceflight-ebook/dp/B0031AI0X0/ref=sr_1_1?ie=UTF8&qid=1386444444&sr=8-1&keywords=digital+apollo) is an excellent book for learning about the AFC and the struggles of human/machine interaction during the Apollo program.

author: Rick Law
author_rank: Super Contributor
timestamp: December 07, 2013, 11:44:43 pm
content: Quote from: walshms on December 07, 2013, 05:58:03 amHis significant role in actually taking us into orbit post-WWII is why I posited he could have achieved orbit even within the WWII timeframe - for all practical purpose, doing so totally digital-computer-less.

author: walshms
author_rank: Regular Contributor
timestamp: December 07, 2013, 11:57:57 pm
content: Quote from: Rick Law on December 07, 2013, 11:44:43 pmOh -- I see, I misunderstood what you meant by that. If he could have, it would have been a pretty spectacular achievement. The technology of the day wasn't really capable of that fine a level of control; if an orbit could have been achieved, it would likely have been a very unstable orbit, and would likely have come back down pretty quickly. I wouldn't have bet on that.Sputnik's launch and successful orbit owed its success to Russian innovation in the sort of navigation that was needed to make it work, but even that was rudimentary. It did work though, and that was probably the first real system capable of achieving a stable orbit.

author: Rick Law
author_rank: Super Contributor
timestamp: December 07, 2013, 11:58:57 pm
content: Quote from: Wytnucls on December 07, 2013, 05:26:13 amIt has been proven it can be done - but it was done because there was no other choice.The Apollo13 team pretty much did exactly that: With no on-board computing power or on-board navigation systems; using just the "Abort Guildance System" from the lunar module, they managed to get to the moon to the point they wanted (no longer for a landing but for gravity assisted return) and managed their way back for a safe landing.That it can be done does not mean it was a good idea. They had no choice after the accidental explosion.When I think about it, I am amazed at how much they (they=people before computer) achieved.

author: walshms
author_rank: Regular Contributor
timestamp: December 08, 2013, 12:03:05 am
content: Quote from: Rick Law on December 07, 2013, 11:58:57 pmThe AGS was a computer though; just a smaller, less capable one. If they didn't have that, they'd likely have risked turning on the AGC for the burn that brought them home, and done whatever they could to minimize further power consumption in turn. I don't think anyone really believed that it would have been possible without at least some computational capability.

author: Homer J Simpson
author_rank: Super Contributor
timestamp: December 08, 2013, 12:16:41 am
content: Here is another video from 1968 on Apollo guidance and navigation. I always had a tough time trying to get my head around how to calculate the whole earth to the moon problem.This is a half hour long but does a pretty good job of explaining it.The more I research on the Apollo program and what was accomplished at that time the more impressed I am with it.KT

author: IanB
author_rank: Super Contributor
timestamp: December 08, 2013, 12:25:37 am
content: Quote from: Homer J Simpson on December 08, 2013, 12:16:41 amFor an analogy of how difficult it is, try playing Angry Birds, and in particular consider the little yellow bird. Note how you launch the bird on a curved trajectory, and when it is pointing in the right direction you tap it to "boost" it at the target you want. In the game the target is relatively near, and yet it is still difficult to get the aim right. Suppose the target was 100x further away, and then imagine how many attempts it would take to hit it. In the game you get as many attempts as you like; on an Apollo mission you only get one try. If you get it wrong in real life you die in space. (In real life you can't suppose to keep adjusting your direction every time you are off target as you don't have that much fuel on board. You get to "shoot" once or twice and that's it.)

author: walshms
author_rank: Regular Contributor
timestamp: December 08, 2013, 05:08:45 am
content: Quote from: Homer J Simpson on December 08, 2013, 12:16:41 amYou're not alone. Most of the people I know wouldn't have a clue about how to do it, and the few that I know that understand it well still tell me that they're not sure that they'd have had the guts to commit the lives of the astronauts to their calculations. The people that made Apollo work were unique; they thrived in that pressure-cooker environment. I would have loved to have been a part of it.. but I was only old enough to watch it happen, not participate.Every once in a while, I listen to the flight director's loop for the Apollo 11 landing on the moon. You can tell right away that most of the people there were young, but there were a couple of old hands steadying the ship, so to speak. Eugene Kranz was the flight director, and his team was absolutely stellar. When during the lunar landing, the computer started throwing 1201 and 1202 errors (executive overflow, meaning the computer had to throw out lower priority tasks to keep up with what was going on and continue to run the highest priority tasks) the computer engineer (I think his name was Jack) told Steve Bales that the errors were understood and that it was okay to proceed. Steve had to make the call to recommend they abort or continue, and he made the call to continue. Gene Kranz accepted that judgment without question -- he knew his team was good.Steve was in his 20s at the time. Imagine making that call! Still amazes me.QuoteGood! That's what we should all be doing. This is a piece of history that has more on offer than most people realize. I've built up a bit of a collection of Apollo materials, and spent a lot of time learning as much as I could about it. I also had the very good fortune to meet a few of the astronauts (but unfortunately, none of the Apollo astronauts -- only ones who flew in the shuttle.) They all have unique stories to tell, and they've filled me with awe and wonder.

author: marshallh
author_rank: Unknown
timestamp: December 08, 2013, 05:20:41 am
content: Get Gene Kranz's autobiography. It is an amazing read, it got me more fired up and motivated to do quality work then anything else in a long time.http://www.amazon.com/Failure-Is-Not-Option-Mission/dp/1439148813Chris Kraft's is also great. It is somewhat more sober and technical (just like himself) recounting his days at NACA and his overseeing the birth of NASA all the way through the shuttle program.http://www.amazon.com/Flight-My-Life-Mission-Control/dp/0452283043/If there was something today that would be as difficult and for such an amazing end result I would be all over it. These kinds of things don't come around very often.

author: walshms
author_rank: Regular Contributor
timestamp: December 08, 2013, 05:24:08 am
content: Chris did a talk at MIT as part of a class on the systems engineering of the Shuttle; one of the professors that taught the class was himself an astronaut, and flew on the shuttle. (I'm blanking on his name just at the moment... I probably ought to get some sleep.)It might be up on YouTube. I know it's up on MIT OCW.

author: marshallh
author_rank: Unknown
timestamp: December 08, 2013, 05:57:50 am
content: Quote from: walshms on December 08, 2013, 05:24:08 amFound it and watchinghttp://ocw.mit.edu/courses/aeronautics-and-astronautics/16-885j-aircraft-systems-engineering-fall-2005/video-lectures/lecture-17/

author: TerraHertz
author_rank: Super Contributor
timestamp: December 08, 2013, 07:35:33 am
content: There are some good links turning up in this thread. Thanks to everyone.Here are some more:20120425http://www.ibiblio.org/apollo/links.htmlVirtual AGC — AGS — LVDC — GeminiDocument Library Page - Apollo and Gemini Computing Systems20130101https://www.eevblog.com/forum/chat/12-layer-board-surface-mount-components-it's-all-so-1960s!/msg176699/#msg176699Topic: 12 layer board? Surface mount components? It's all so 1960s! (Read 137 times)htt p://www.youtube.com/watch?v=J0ggqY7vnAwThe Apollo Saturn V Launch Vehicle Digital Computer (LVDC) Circuit Board (Frann's investigation)http://www.vintchip.com/mainframe/nasalvdc/apollolvdc.htmlSo, here's part one of the service manual for the whole computerhttp://www.vintchip.com/mainframe/nasalvdc/LaboratoryMaintenanceInstructionsForLVDC-Volume1-GeneralDescriptionAndTheory.pdf20130720http://klabs.org/history/build_agc/Block I Apollo Guidance Computer (AGC): How to build one in your basement (He actually did!)http://klabs.org/richcontent/Misc_Content/AGC_And_History/AGC_History.htmhttp://klabs.org/history/history_docs/mit_docs/index.htmhttp://klabs.org/history/apollo_experience_reports/index.htmhttp://en.wikipedia.org/wiki/Apollo_Guidance_Computerhttp://klabs.org/mapld04/program_sessions/session_g.htmlhttp://hrst.mit.edu/hrs/apollo/public/index.htmhttp://downloadsquad.switched.com/2009/07/20/how-powerful-was-the-apollo-11-computer/How powerful was the Apollo 11 computer? (20090720)------------Also, here's a small fanciful thought I noted down earlier this year.20130720While reading an article about the Apollo Guidance Computer( see Notes\Space\Moon\!_Apollo_technical_archives\build_AGC )It occurred to me that it would be fun to develop an open-source _real_ space navigation software package. Just in case .. um... someone happened to come up with a Scal... ah... breakthrough physics reactionless drive.Purpose: Serve as navigation and flight control for an 'ideal spacecraft' - something like a reactionless-thrust-drive UFO. In general, a space and atmosphere capable craft. Anti-gravity, or whatever you want to call it. Able to produce multiple Gs of acceleration and ideally also able to maintain an internal controlled-G environment independent of actual acceleration.Regardless of the drive technology and capabilities, the problems of space navigation remain much the same. Just with somewhat less restrictive manifolds for continuous thrust and unlimited operation-time drive technology.Thoughts on what that software system would require* Maintains database of known objects, incl characteristics, velocities, mass, orbits, etc.All data must include quantified degree of uncertainty, sub categorized as passive measurement uncertainty vs potential subterfuge.Object data may include surface & structural models.Objects may be static (planets, stars, moons, rocks, etc) or active Newtonian (other slow craft), or active relativistic (near light speed craft.)They may be large (creating significant gravity wells), small (just collision hazards), or potential active threats (mines, hunter-killers, etc.)The craft itself is another object in this database, and includes all operational & structural information about the craft.* Object database able to include very large numbers of objects. Eg Orbital satellites & junk, planetary systems incl moons, asteroids & comets. Star systems, galactic volumes, etc.* Must include ability to map dust/gas density in large volumes of space.And other relativistic navigational hazards.* Should include an electrostatics and space plasma conductance physics model, as these forces and effects are much more significant than commonly believed.* For active objects, details can include armaments, capabilities, etc.* Maintains details of this craft's projected trajectory and potential envelope given available maneuvering capabilities.(Ditto as for all other craft, given their known maneuvering capabilities.)* External input of updates to the database at any time. Eg from radar ranging, optical tracking, data packets fromdistant friendlies, etc.* Able to drive assorted sensing systems (optical, radar, scalar) to scan for objects, and develop data on object characteristics.* Able to point and auto-fire assorted weapons systems - lasers, ultra-velocity projectiles, fire and forget missiles, etc.* Flight control. Can run manual or autopilot. Either mode takes input in either absolute (direction & acceleration)or desired path/destination/intercept selections.* Path planning given desired destinations/intercepts.Able to calculate multiple alternatives including gravity fly-by assists, and present options graphically.* Keyword coded action scripting, including battle attack/evasion strategies.* Able to run forward and reverse time projections, give differing sets of data variation, while maintaining actual situation and projection given no change.* Able to run in classical or relativistic modes.Display* Able to present scenario data in 2D, 3D 3rd-person, and HUD format.* Scale: Can operate on a wide range of scales, from interstellar, down to short range near-surface flight.* On close up scales, database info on object surface/internal details visible.* Timescale: Able to process mission durations of thousands of years.References-----------http://www.xkcd.com/1244/http://www.explainxkcd.com/wiki/index.php?title=1244:_Six_Wordshttp://en.wikipedia.org/wiki/Orbiter_(simulator)http://en.wikipedia.org/wiki/Kerbal_Space_Programoberth kuiper maneuverkerbal space programhttp://everist.org/texts/Fermis_Urbex_Paradox.htm

author: Rick Law
author_rank: Super Contributor
timestamp: December 08, 2013, 08:18:55 am
content: Quote from: Mechatrommer on December 07, 2013, 11:34:15 amI think beyond a certain point, it is more philosophical than technical as to what IS a computer. I am still looking for the line that divides calculator and computer.While few would argue PDP8 is or is not a computer. Yet if you can pack 2x or 3x PDP11 level of computing power into a child's toy yet few would say that is a computer...

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 08, 2013, 08:33:40 am
content: too long of a list, only few points...Quote from: TerraHertz on December 08, 2013, 07:35:33 ammoving an object without reaction? again another the breaking the "Newton Law" physics. just like "Euclid Straight Line" is wrong notation found in quantum mechanic(?) discussion.Quote from: TerraHertz on December 08, 2013, 07:35:33 amagain another "antigravity" dream. how much capability we have to control gravitation? its only in the "back to the future" hollywood movie. unless we can make supermagnet the size of earth itself, forget controlling gravitation... for now. how do you make "simulation" of something you (human) dont understand?Quote from: TerraHertz on December 08, 2013, 07:35:33 amditto! before, its done by human now its done by computer. landmarking, beaconing, triangulation etc. add the fancy bell and whistle to computing such as polynomial averaging, kalman filtering or whatever. now computing power is holy. regardless of how much computing power we have, computer is a GIGO machine. unless you can put enough AI in it, intelligent enough not to need any input it decides by itself. but then how do you put intelligent in it if you dont have the intelligence in the first place? (brain the supercomputing power?) how do you teach (simulate) computer to navigate quasar, black/wormhole? or maybe even blend into higher dimension world? if we human dont understand it by ourself?imho computer for space craft (just as in robotics) is not comparable to a watch or the PC on our desk, its a combination of sensories input, control feedback output, computation, navigation and AI (software) that why maybe the boundary of each discipline is quite vague. now dont get me wrong i dont say we dont have to keep moving. awesomeness and respect to what we've (we? american?) achieved no doubt, but are we certain where is our place in the universe? if our sun going supernova (before we can achieve anything usefull) where will we go?move on guys! dont build analog PC and waste the time redoing past mistakes. respect to our ancestors is in the history book or utube vids like this, try to "fell" them how much hope they put on us. i just dont get it why people have to redo archaic stuffs it belongs in the museum. build something more usefull, such as cheap but quality OSHW PSU, cheap coil winder, cheap Alhteeum PCB designer, cheap diff or current probe, cheap OSHW this and that, its more worth of the time imho. time is gold. FWIW YMMV.

author: moepower
author_rank: Contributor
timestamp: December 08, 2013, 08:44:39 am
content: A fascinating yet lengthy read for computer geeks ishttp://www.doneyles.com/LM/Tales.htmlIt describes the Apollo computer in depth and the famous 1201/2 alarm that occurred on the first lunar landing. Sort of like a bluescreen-of-death except their computer was fault-tolerant enough to ride through that, unlike Windows.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 08, 2013, 01:10:52 pm
content: Mechatrommer.... good grief. Not sure if excessively literal mind, or on drugs.Anyway. There are exceedingly detailed and realistic flight simulator games for things like the space shuttle. It would make a cool foundation for a multi-player space combat game, to have a fully implemented 'real' spaceship navigation simulation package.Though it would be something you'd have to play over quite lengthy periods.Edit: To clarify: 'real' spaceship, as in what would be nice in fantasy.

author: BravoV
author_rank: Super Contributor
timestamp: December 08, 2013, 01:18:49 pm
content: Quote from: TerraHertz on December 08, 2013, 01:10:52 pmNah .. its norm around here and not that surprising anymore, just check out his sig.

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 08, 2013, 04:09:19 pm
content: Quote from: BravoV on December 08, 2013, 01:18:49 pmand his, and the people in powerseriously answer me! (if you are not on drug, instead of just empty mouth or bashing words or too concerned with sig) how do you simulate antigravity? or maybe i read it incorrectly, do you expect to find out how to device antigravity from the simulation made? (if so that is a serious chicken and egg problem)

author: danb35
author_rank: Contributor
timestamp: December 08, 2013, 05:19:24 pm
content: Quote from: Mechatrommer on December 08, 2013, 04:09:19 pmI think the point is that the simulation assumes no mass used for propulsion, i.e., that thrust can simply be applied to the vessel without simultaneously changing the vessel's characteristics. That also is a pipe dream at present, but it no doubt greatly simplifies the math for the simulation.

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 08, 2013, 05:26:09 pm
content: oh i get it. the antigravity simulation is already there, videogame.

author: geo_leeman
author_rank: Regular Contributor
timestamp: December 08, 2013, 09:29:02 pm
content: Quote from: marshallh on December 08, 2013, 05:20:41 amI met Gene when I was working at NASA some time back... He is an absolutely incredible individual and motivated me to work harder on ever more complex problems. Hearing him talk and seeing his passion was incredible. He recounts the landing with such great memory we felt like it was happening in real time.

author: walshms
author_rank: Regular Contributor
timestamp: December 08, 2013, 10:21:12 pm
content: Quote from: geo_leeman on December 08, 2013, 09:29:02 pmColor me envious; I would have loved that opportunity. There was no doubting his passion; listening to him keep mission control on task and the calm, professional way he conducted himself during the A11 landing was all I needed to know that.Well, there was the moment when he yelled "Keep the chatter down in this room", but other than that he was as cool as a cucumber.

author: BBQ
author_rank: Regular Contributor
timestamp: December 08, 2013, 11:06:04 pm
content: Not to spoil the party, but how far did the Soviet Union progress in their moon mission?

author: free_electron
author_rank: Super Contributor
timestamp: December 09, 2013, 01:10:48 am
content: Quote from: Mechatrommer on December 05, 2013, 05:42:53 amI'll introduce you to a friend of mine. He sometimes goes under the monniker "Dr Rendez-vous" , i'm sure he'll have some words to say about your remark. After all he figured out the mathematics on how to meet up two spacecraft and proved it duriing his Gemini and Apollo days...I dove with him in 2000 on the Maldives. Met him again In the hangar bay of the Hornet July 205 of 2009 they had their little 40th celebration. Got a couple of books signed by him.

author: dannyf
author_rank: Super Contributor
timestamp: December 09, 2013, 01:27:04 am
content: Per a certain movie, the russians landed also on the moon - just the wrong part of it, unfortunately.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 09, 2013, 01:29:02 am
content: Quote from: BBQ on December 08, 2013, 11:06:04 pmSame as usual. Brilliant engineering, screwed over by politicians.The Engines That Came In From The Cold! (The Soviet Moon Program)Better engines than the US could build.2008http://www.forteantimes.com/features/articles/1302/lost_in_space.htmlLost in SpaceWhat really happened to Russia's missing cosmonauts? An incredible tale of space hacking, espionage and death in the lonely reaches of space.Edit, to add:http://defensetech.org/2012/01/06/inside-an-abandoned-soviet-rocket-motor-factory/Inside an Abandoned Soviet Rocket Motor Factoryhttp://www.techgraffiti.com/the-girl-who-broke-into-a-russian-rocket-testing-factoryThe Girl Who Broke Into a Russian Rocket Engine Testing Facilityhttp://io9.com/the-fading-grandeur-of-abandoned-soviet-space-facilitie-456896333http://www.russianspaceweb.com/phobos_grunt_2010.htmlhttp://www.urbanghostsmedia.com/2010/09/abandoned-russian-space-shuttle-2/(Google will find you lots of pics of the abandoned Buran space shuttle in various states of dilapidation.)I'm also trying to re-find the URL to a spectacular Urbex photo-tour of a huge abandoned Russian space-environment test facility. But seems my filing system *and* google fail on that one.

author: nctnico
author_rank: Super Contributor
timestamp: December 09, 2013, 02:41:42 am
content: Quote from: BBQ on December 08, 2013, 11:06:04 pmThey did something even more amazing: they send verhicles to the moon and controlled them from earth:http://en.wikipedia.org/wiki/Lunokhod_programmeThere is a documentary somewhere online but I can't find it right now.The Russians developed a lot of remote controlled robot technology which was first visible when they used robots to try and cleanup Chernobyl. Until then the entire lunar vehicle program was a well kept secret. Even the current Mars rovers benefit from the knowledge the Russians have gained in the past.edit: Found the torrent link: magnet:?xt=urn:btih:2EC99DFE8843A42B4D6D525251EC4F22FEBEB34F&dn=ZED.Tank.on.the.Moon.x264.720p.AC3.HDTV&tr=http://www.mvgroup.org:2710/announce&tr=udp://tracker.openbittorrent.com:80&tr=udp://tracker.publicbt.com:80&tr=udp://tracker.istole.it:80&tr=udp://open.demonii.com:80&tr=udp://tracker.coppersurfer.tk:80

author: amyk
author_rank: Super Contributor
timestamp: December 09, 2013, 06:57:46 am
content: The most interesting thing IMO about the AGC design was that it was built entirely using NOR-3 gates - in surface-mount packages. At a time when there was no CPLDs, FPGAs, nor VHDL.

author: moepower
author_rank: Contributor
timestamp: December 09, 2013, 08:31:11 am
content: Quote from: marshallh on December 08, 2013, 05:20:41 amI just read these books last month and I agree. They are an amazing read. I would also add the book "Apollo EECOM - Journey Of A Lifetime" by Sy Liebergot, who was one of the Apollo flight controllers and was the focal point of the Apollo 13 disaster.Some interesting interview transcripts too onhttp://www.jsc.nasa.gov/history/oral_histories/oral_histories.htmJack Garman's interview gives further information about the Apollo Computers.

author: geo_leeman
author_rank: Regular Contributor
timestamp: December 09, 2013, 01:12:47 pm
content: Quote from: walshms on December 08, 2013, 10:21:12 pmYep, it was pretty great. Also worth noting that there is an great visualization of all loop traffic during the landing here:http://www.firstmenonthemoon.com/

author: walshms
author_rank: Regular Contributor
timestamp: December 09, 2013, 08:18:13 pm
content: Quote from: BBQ on December 08, 2013, 11:06:04 pmThe N1 was a failure... they never made it with a human, only robots.

author: walshms
author_rank: Regular Contributor
timestamp: December 09, 2013, 08:40:28 pm
content: Quote from: geo_leeman on December 09, 2013, 01:12:47 pmNice... that cleared up one or two of the bits of interaction that I wasn't entirely clear on. Whoever put that together did a really good bit of work.

author: Homer J Simpson
author_rank: Super Contributor
timestamp: December 10, 2013, 02:34:54 am
content: Moon Machines (2008): The Navigation ComputerKT

author: geo_leeman
author_rank: Regular Contributor
timestamp: December 10, 2013, 04:20:29 pm
content: Quote from: walshms on December 09, 2013, 08:40:28 pmI believe they won some sort of visualization award for the work earlier this year. Loops were (and still are) just darn confusing sometimes!

author: Homer J Simpson
author_rank: Super Contributor
timestamp: December 10, 2013, 05:58:23 pm
content: Here is another link to a great site with a lot of Apollo information for those who are interested.I don't think this one has been posted yet.Apollo Lunar Surface Journal.http://www.hq.nasa.gov/alsj/main.htmlKT

author: chrisc
author_rank: Unknown
timestamp: December 10, 2013, 06:10:54 pm
content: Quote from: Homer J Simpson on December 10, 2013, 05:58:23 pmGood link. I found this (from the camera section) interesting:"The Data Camera was modified to prevent accumulation of static electricity. When film is wound in a camera, static electricity is generated on the film surface. Normally, this electricity is dispersed by the metal rims and rollers that guide the film, and by the humidity of the air. In a camera fitted with a Reseau plate, however, the film is guided by the raised edges of the plate. As glass is a non-conductor, the electric charge that builds up at the glass surface can become so heavy that sparks can occur between plate and film - especially if the camera is used in a very dry environment or in vacuum. Sparks cause unpleasant patterns to appear on the film and can be a hazard if the camera is used in an atmosphere of pure oxygen. To conduct the static electricity away from the Reseau plate in the Data Camera, the side of the plate facing the film is coated with an extremely thin conductive layer which is led to the metallic parts of the camera body by two contact springs. Contact is effected by two projecting silver deposits on the conductive layer."

author: Homer J Simpson
author_rank: Super Contributor
timestamp: December 10, 2013, 07:34:36 pm
content: Here are some great hi rez pics of inside the LMhttp://www.hq.nasa.gov/alsj/a15/a15LMCloseOutPhotos.htmlKT

author: G0HZU
author_rank: Super Contributor
timestamp: December 10, 2013, 10:15:02 pm
content: Quote from: walshms on December 06, 2013, 09:43:52 pmI agree but I suspect dannyf would have a go...Did Wallace and Gromit make it to the moon without a computer?

author: VintageTekFan
author_rank: Regular Contributor
timestamp: December 10, 2013, 11:46:51 pm
content: Quote from: G0HZU on December 10, 2013, 10:15:02 pmWallace couldn't make it into his clothes without a computer...They were, theWrong Trousers, however.Edit: Link.

author: G0HZU
author_rank: Super Contributor
timestamp: December 11, 2013, 01:10:30 am
content: QuoteA good point, well made...

author: walshms
author_rank: Regular Contributor
timestamp: December 11, 2013, 03:38:33 am
content: Quote from: geo_leeman on December 10, 2013, 04:20:29 pmSure are... I wasn't aware that Charlie Duke actually suggested that they be quiet; I never actually heard that clearly enough. All I remembered was Gene saying "The only call-outs from now on will be fuel..."

author: chrisc
author_rank: Unknown
timestamp: December 11, 2013, 04:14:35 am
content: Apparently even if you've just won the space race by strapping yourself onto the top of 3,000 tons of high explosive and steering a tin can to the moon and back, you still have to clear customs

author: walshms
author_rank: Regular Contributor
timestamp: December 11, 2013, 06:58:16 pm
content: Quote from: chrisc on December 11, 2013, 04:14:35 amAnother clear example of a self-important governmental twit taking things one step too far. Amazing. I'd have asked "is this really necessary?", especially when they wouldn't have had a clue what, if anything, there was to be concerned about. It certainly wouldn't have been insects...

author: G0HZU
author_rank: Super Contributor
timestamp: December 11, 2013, 11:22:02 pm
content: Presumably they would have also been asked if they were carrying anything in their luggage that had been given to them by any strangers (aliens?) they met prior to takeoff from the moon.Seriously though, this was probably a well anticipated bit of red tape they all enjoyed taking part inI bet the person who typed it up will never forget that special moment

author: chrisc
author_rank: Unknown
timestamp: December 12, 2013, 12:33:58 am
content: Quote from: G0HZU on December 11, 2013, 11:22:02 pmI'd tend to agree with that. I suspect they all found it a bit amusing."Mr Armstrong, do you have anything to declare? No? Did you visit any derelict spaceships or come into contact with alien face-huggers in the last ten days? No? Excellent, please sign here"

author: hgg
author_rank: Frequent Contributor
timestamp: December 12, 2013, 03:30:53 am
content: Quote from: chrisc on December 10, 2013, 06:10:54 pmThis is interesting actually and not only about the camera. How did they get away with staticelectricity on the Moon in general? I assume that given the environmental conditions on the Moon,just a walk or a ride with the rover would have created a huge amount of static! What happenswhen they go back in the LEM? Lets try to input some vebs and nouns and see what happens...

author: TerraHertz
author_rank: Super Contributor
timestamp: December 26, 2013, 06:09:53 am
content: Something new:http://www.dailymail.co.uk/sciencetech/article-2528936/One-small-click-man-Nasa-releases-17-000-photos-Apollo-program-including-rare-shots-mission-13.htmlOne small click for a man: Nasa releases more than 17,000 photos from the Apollo programme (including rare shots from mission 13)Naturally the dailymail don't provide a link. But it's easy to find:Lunar And Planetary Institute - Apollo Image Atlashttp://www.lpi.usra.edu/resources/apollo/Next question: where's the torrent of the entire archive?Edit: Ah CR*P! When I actually start looking through the images, they are ALL scanned atpatheticallylow resolution. And it's NASA's fault. Quote:This catalog was created using a set of images received from the NASA Johnson Space Center. The images were created as follows:The Apollo film was scanned using a video camera, with a resolution of over 700 lines, to create a digital file.Each frame was digitized as a 24 bit color image at 756 x 486 pixels, producing a file of approximately 1.1 megabytes in Targa format.The Targa images were then processed to produce a 640 x 480 image at 72 ppi in JPEG (JPG) format. These images were also (significantly) compressed, reducing the final file size to about 40 kilobytes on average.But actually when you fetch them they are 450x450, for the 70mm Hasselblad film.70mm film, scanned to 450x450 pixel resolution? That's criminal. Screw you *again* NASA.This is even more annoying than finding out NASA are color-shifting all the Mars images.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 26, 2013, 07:44:53 am
content: "Color-shifting Mars images" - I should have been more specific - the images from Spirit and Opportunity. From Curiosity, I don't know since I've never been able to find an original image of the color reference swatches set taken on Earth.Anyway, I happened to look at the MSL site just now, and noticed this. It's a bit sad. I guess Curiosity won't have a very long exploring career, if the wheels are deteriorating at this rate.Left-Front Wheel of Curiosity Rover, Approaching Three Mileshttp://photojournal.jpl.nasa.gov/jpeg/PIA17751.jpgFromhttp://photojournal.jpl.nasa.gov/targetFamily/Mars

author: amyk
author_rank: Super Contributor
timestamp: December 26, 2013, 12:43:46 pm
content: Quote from: TerraHertz on December 26, 2013, 06:09:53 amDon't know why you're complaining but take this one for example:http://www.lpi.usra.edu/resources/apollo/frame/?AS13-61-8747Thepreviewis 450x450... click "Print Resolution" link below to get the full resolution, which in this one happens to be 3900x3900.Their server is slooooooow, so you have to wait a bit.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 26, 2013, 11:38:53 pm
content: Quote from: amyk on December 26, 2013, 12:43:46 pmDoh. Thanks for pointing that out, I'd missed it. After clicking through a few of the first thumbnail images, and getting only what are effectively slightly larger thumbnail images which don't link to anything bigger, I backed out to here:http://www.lpi.usra.edu/resources/apollo/processing/where they describe the scanning process used. And they say:QuoteThey then describe further processing by LPI to produce the 120 x 120 pixels and 450 x 450 pixels images I'd seen. No mention at all of decently hi-res images, and their final words are:QuoteAt which point I just went Nooooooooooooooo! and gave up. 'Obtained'? Obtained from NASA? Oh sure.Apparently their introductory description is inaccurate.

author: TerraHertz
author_rank: Super Contributor
timestamp: April 28, 2014, 04:37:49 am
content: Something relevant I came across today, viahttps://news.ycombinator.com/item?id=7657876Computers in Spaceflight: The NASA Experiencehttp://history.nasa.gov/computers/Part1.htmlThe link is to "Part I : Manned Spacecraft Computers"There are three parts total:http://history.nasa.gov/computers/Part2.html(Part II : Computers On Board Unmanned Spacecraft)http://history.nasa.gov/computers/Part3.html(Part III : Ground Based Computers for Space Flight Operations)The full index:http://history.nasa.gov/computers/contents.html(it's just the "Index Page" button from the bottom)

author: miguelvp
author_rank: Super Contributor
timestamp: April 28, 2014, 04:41:39 am
content: Since this thread resurrected, maybe it's time to do something with that module Fran sent you Dave.Don't ask me what, I haven't a clue on hybrids.