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Getting to the Moon was only half the job
July 21, 2014 2:57 PM   Subscribe

On July 21th, 1969 Neil Armstrong and Buzz Aldrin waited within paper thin walls on the surface of the Moon. Hours ago they had made history by being the first humans to land and walk on its surface. Now the only thing left to do was take off. All that entailed was performing the final test of the Lunar Module: launching from the lunar surface with no on-site support or possibility of fixes if something failed.

The earliest serious thought about landing on the Moon occurred in the 1950s. Even as America worked to launch its first satellite and then human, engineers and scientists were putting thought into what would come later.

Grumman Aircraft Engineering was a young aircraft firm, known for its series of 'Cat' planes in WWII. With the arrival of the Space Age, the company sought to make a name for itself by concentrating on spacecraft for the Moon, hoping to get a jump on competitors.

After President Kennedy made landing on the Moon and returning safely a national priority in 1961, NASA focused on meeting the goal by the end of the decade. One of the major tasks was figuring out the method or mode of how to do it.

The first mode was called Direct Ascent, which involved a single ship launching from Earth, landing on the moon and then returning, fully intact, to Earth. While considered optimal, this single ship would require massive feats of engineering, along with huge amounts of fuel to power it.

The second method was Earth Orbit Rendezvous (EOR), where two rockets would launch into Earth orbit. One would contain the astronauts, the other fuel for the voyage. After reaching orbit, the two spacecraft would dock, and head to the Moon. Once there, a single ship would land on the surface, astronauts would explore and then the spacecraft would lift off and return to Earth. Considering the huge structure needed for Direct Ascent, EOR was considered a vast improvement, though it would still require massive resources to launch two rockets and sustain a single vehicle through the journey.

Eventually a third method, Lunar Orbit Rendezvous (LOR), was championed by NASA enginner John Houblot, though it had been first propsed by Ukrainian engineer Yuri Kondratyuk in 1916. The chief benefit of LOR was that it 'shed' parts of the rocket at various stages. Rather than sending a huge spacecraft, two would make the voyage. Both would be launched on a single rocket into Earth Orbit. Once there, the Command/Service Module (CSM) would dock with the LM and haul it the Moon. In lunar orbit, the LM would undock and use its Descent Module to land. When it came time to leave, only a small part of the LM, the Ascent Module would launch. Back in lunar orbit, it would dock with the CSM, and then jettisoned as the astronauts returned in only the CSM. Then, just before re-entry, the Service module would be jettisoned and only the Command Module would land back on Earth. Using this method of constantly shedding no longer needed hardware (and its fuel), tremendous weight could be saved overall, which required less fuel. Though the launching rocket would be 3,300 tons, the weight of the lone returning part, the Command Module would only be 6 tons. This was doable.

Though originally scoffed at by NASA for its complexity, LOR was eventually chosen as the method for Apollo. Gruman had been doing its own internal studies, in an effort to win a contract in the Apollo program. Though they failed to win the competition for the CSM, their studies jibbed closely with NASA's and in 1962, they were awarded the almost $400 million dollar contract to design and build the LM. The final contract was actually more than Gruman had bid, as NASA was insistent on working with Gruman to come up with the final design for this spacecraft that would fly outside of an atmosphere.

Gruman appointed Tom Kelly, who headed up most of the internal studies, as Project Engineer. Over the next seven years, he and his team worked long hours, often six or seven days a week, to design and build small mockups, then life size mockups and finally flight capable spacecraft that would do the most imporant of President Kennedy's goal: landing men on the Moon and returning them safely. To do this, engineers had to radically rethink every idea on how to fly and land a ship, as demonstrated in this clip on LM design from episode nine of HBO's mini series from the Earth to the Moon.

Yet as innovative as Kelly and other engineers were, a price was paid in repeatedly missing deadlines. Its first unmanned flight test was scheduled for April of 1967, but repeated delays in refining the spacecraft pushed the date back to January of 1968. Launched as Apollo 5, the LM was sent up with no landing legs since it was just test to see if it was capable of flying in space and testing the Descent and Ascent engine. Though there were a few problems in Earth orbit, NASA deemed the flight a success, canceled a second unmanned test and moved forward with the first manned flight.

After testing the Command and Service Module on Apollo 6 and 7, Apollo 8 was scheduled to test the test CSM and LM together in near Earth orbit. But manufacturing problems again delayed the flight and NASA went ahead with testing the CSM in lunar orbit on Apollo 8 in December of 1968.

Apollo 9 lifted off in March of 1969, as a fully manned test of the all the Apollo spacecraft components at once. Since two spacecraft would be operating in space at the same time, the crew was allowed to name the two craft, choosing Gumdrop for the CSM and Spider for the LM. For ten days, the crew put both spacecraft through their paces, docking and redocking repeatedly and then finally testing the Descent engine firing and separation and ignition of the Ascent stage. Everything worked well, which presented NASA with an interesting question: land on the Moon next or continue testing?

There were advocates on both sides, but in the end it came down to the hard work of building an LM to meet specific weight goals. The next production model was still too heavy. It might be able to land on the Moon, but it would never be able to lift off. The model after this, scheduled for Apollo 11, would be light enough, but was still months away from being complete. With the end of the decade looming and President Kennedy's goal to land on the Moon by 1970, it was decided to do a full up testing of the lunar landing. The Apollo 10 crew would go to the Moon and perform a dry run of a lunar landing, dropping to 50,000 above the surface before heading back to orbit.

Launched in May of 1969, Apollo 10 headed to the Moon, putting Mission Control, deep space communicaitons and the two spacecraft though their paces. There were minor, human related problems that caused the LM to veer wildly out of control as it ascended from the 50K mark, causing one of the astronauts to exclaim "Son of Bitch" over the open air mic and eventually having to apologize for it due to complaints. Still the mission was a sucess, everything performed well and checklists were changed to prevent the problems that did occurr.

All of this leads us to Apollo 11 and its successful landing on July 20th, 1969. The LM had continued performing as well as before as Kelly and others monitored its progress from a backroom in Mission Control. But now, after a historic exploration on another celestial body, it would have to pass its final test. The Ascent module would have to fire its engine, while simultaneously igniting explosive bolts to separate from the Descent Module and lift off from the Moon. It would have to work all by itself, there was no launch crew or tower, no way to fix any problems. Seven years of design, contruction and testing would have to work or two men would die, alone and far from the home, as the world watched.

But it did work, pf course. It worked for five more landings, each spending progressively longer time in the harsh environment of the lunar surface. The LM also worked for far beyond its original specs on Apollo 13, keeping three men alive longer than it was designed for as they limped home afer an explosion in the Service Module.

The Apollo program eventually ended with Apollo 17. Six descent modules from Apollo 11, 12, and 14-17 still remain on the Moon. The Ascent Modules for those missions were either left in decaying orbit around the Moon or intentially crashed into the surface to test seismographic instruments left by the astronauts.

The descent module for Apollo 10 crashed into the surface after being jettisoned at 50,000 above the surface, while the entire LM for Apollo 4, 9 and 13 burned up in Earth's atmosphere. The Lunar Module on display at the National Air and Space Museum in Washington DC is the model intended for that second unmanned test.

The only surviving flown Ascent module is from Apollo 10, code named Snoopy. It was jettisoned after the astronauts returned to the CSM and is in an unknown orbit around the sun. Tom Kelly passed away in 2002.
posted by Brandon Blatcher (67 comments total) 176 users marked this as a favorite

 
The time stamp on this post almost exactly when Apollo 11 lifted off from the Moon.

If you'd like to test your ability to land on the Moon, there's a couple of options.
posted by Brandon Blatcher at 3:00 PM on July 21 [17 favorites]


A couple of my favorite space photos, featuring Apollo 9's "Spider:"

Spider in Earth Orbit

Spider Over the Ocean


It's just so surreal seeing the Lunar Module dangling above the Earth
posted by Auden at 3:10 PM on July 21 [7 favorites]


Summer of '69 was an amazing time to be an 11-year-old space nerd. We were on vacation on a lake in northern Indiana, but luckily the cabin had a tv and could bring-in a signals just enough to let me "watch" the landing into the wee hours of night.
posted by Thorzdad at 3:12 PM on July 21 [10 favorites]


That must've been cool. Sigh.
posted by wotsac at 3:15 PM on July 21 [3 favorites]


The next thing I knew, it was time to stuff the horse into the airlock. Neil and I were shoving him in there, and the horse was screaming, and the other guy that was with us was yelling, “No, no, no! Don’t launch the horse!” but we said, “Shut the fuck up for a second, and just let us jettison this horse into the infinite blackness of outer space.”
posted by p3on at 3:16 PM on July 21 [23 favorites]


The time stamp on this post almost exactly when Apollo 11 lifted off from the Moon.

I realize this post is remarkably detailed and comprehensive, but I had no idea it was started in 1969!
posted by fairmettle at 3:18 PM on July 21 [2 favorites]


Watching Apollo 11 land on the Moon is actually my earliest memory. Thanks for the detailed background.
posted by happyroach at 3:18 PM on July 21 [1 favorite]


Amazing that this was 45 years ago. This would be a major achievement even now. I remember reading books from that era that were optimistic we'd go to Mars by 1980, but I guess politicians decided to quit while we were ahead.

For rocketry simulation software I'd recommended Orbiter and for the more technical people, OpenRocket. There appears to be an Apollo 11 simulator for Orbiter. Google also pulls up some dedicated programs from 2006 like Eagle Lander. If you just have a casual interest in rocketry, Kerbal Space Program wins hands down... very entertaining but uses real physics; the only downside is it uses its own planetary system. I've learned more about astronavigation from Kerbal than the other programs combined.
posted by crapmatic at 3:19 PM on July 21 [8 favorites]


Project Apollo: A retrospective analysis

Ending Apollo

(this is an excellent post, btw - thanks!)
posted by nubs at 3:31 PM on July 21


There's something quintessentially American about the way this all came about. "Let's shoot a tin can with a couple dudes in it at the Moon, and see if we can hit it! Also we have to do it first!!" So sad that attitude seems to have faded away. I'm talking about Mars of course. Everybody wants to send robots. It's not efficient to send people, it's dangerous, robots can do all the same things as humans, blah blah blah. Fuck robots! We oughtta build a rocket that we're 50% sure will get there and find some fearless, glory-seeking half-crazed cowboys (or cowgirls!) who will fly the thing. You know they're out there. After they take off, erect statues of 'em in their hometowns and give their families a million dollars. We'd be there and back before Hillary's second term ended!
posted by mrbigmuscles at 3:32 PM on July 21 [4 favorites]


Now I sorta feel like maybe we should put a horse into cislunar space.

C'mon, let's do this thing.
posted by aramaic at 3:34 PM on July 21 [1 favorite]


How do you train to land the LM on earth? Well, you build a machine with an engine set-up that can mimic the moon's 1/6 gravity. Fly it high, then set the engine to push up at 5/6 gravity while you mess around with steering thrusters.

And if you're Neil Armstrong, you try not to crash it. Oops.
posted by Cool Papa Bell at 3:35 PM on July 21 [2 favorites]


mrbigmuscles, I give you Mars One.
posted by nubs at 3:35 PM on July 21 [1 favorite]


We oughtta build a rocket that we're 50% sure will get there and find some fearless, glory-seeking half-crazed cowboys (or cowgirls!) who will fly the thing.

Make sure they can do chemistry and math in their heads. The Martian. Fantastic book.
posted by Cool Papa Bell at 3:36 PM on July 21 [11 favorites]


I just read The Martian as well, and loved it.

Thanks for this neat post. When Apollo 11 landed on the moon, my spouse was in a touring company of Mame. He says the cast asked for the night off, but they had a performance anyway. They got VERY lucky with the timing and Neil Armstrong and Buzz Aldrin landed on the moon during intermission. After the show, the cast came out and told the audience (of people who apparently thought it was more important to see Mame than the moon landing, what the hell) that Apollo 11 had been successful.
posted by roomthreeseventeen at 3:42 PM on July 21 [5 favorites]


I really liked Apollo by Bly Cox and Charles Murray. Great account of the program.

Though special mention must also go to the "how astronauts eat" portions of Packing for Mars by Mary Roach.
posted by fifteen schnitzengruben is my limit at 3:43 PM on July 21 [3 favorites]


What a great post.

The astronomy teacher at my well-appointed (we had a planetarium) Midwestern suburban public high school was, basically, a young-earth creationist. I distinctly recall the day he told us everything in the textbook was false. The one piece of evidence I recall was that the lunar landers had long legs in expectation of "moon dust", the lack or which demonstrates that the moon, and therefor universe, are only 6,000 years old.

I knew it was bullshit at the time but it still bothers me to have sat through it.
posted by These Premises Are Alarmed at 3:44 PM on July 21 [4 favorites]






So, best of the web always implies to me that main content in an FPP is in the links - that the FPP itself is really only the framing for the material. (Which is why I sometimes feel funny thanking people for posting FPPs, as who I should really be thanking are the people who authored the links.) Occasionally I consider putting together an FPP based on one of the disciplines I work in, but then I feel awkward about putting too much of myself in the post, if you know what I mean.

Reading this post, though, (and I did, every word from top to bottom), makes me reconsider my assumption about MF's purpose. Maybe telling an interesting story in a compelling manner, and using links to back up claims and flesh out the details, is a legit way of creating an FPP. Certainly I am glad I read this one, even if I only clicked on two links. Thanks, BB!
posted by ianhattwick at 3:59 PM on July 21 [11 favorites]


I grew up post-lunar landing. When the Challenger exploded in front of me on TV, it was traumatic. In spite of that, I was probably an adult before I realized that, when they landed on the moon, they weren't sure they would get there, that they would land or that they'd make it back. I remember feeling pretty shocked - in spite of the Challenger and the Apollo problems, I still had faith that the government wouldn't send people to the moon unless it would work. Denial and faith in science, I guess.
posted by Chaussette and the Pussy Cats at 4:05 PM on July 21 [4 favorites]


The first mode was called Direct Ascent, which involved a single ship launching from Earth, landing on the moon and then returning, fully intact, to Earth.

When I read this I picture a 1950s rocket ship, silvery and phallic, sitting upright on the Lunar surface.

(Great post.)
posted by brundlefly at 4:06 PM on July 21 [2 favorites]


Reminder of the speech Nixon thankfully never had to give.
posted by dismas at 4:10 PM on July 21 [3 favorites]


paper thin walls

For some reason, this fact alone makes me about as nervous as any other detail from the flight.
posted by SpacemanStix at 4:20 PM on July 21 [4 favorites]


Direct ascent is why the SM had the gigantic SPS engine, a derivative of the RL-10. When the LOR decision was made, it was too late to respect the CSM with a smaller module.

To prevent something firing when it should not, policy on the CSM and LM was to pull the breakers sending power to that engine. This works fine, so long as you remember to push the breaker back in before a burn, and don't break the handle off the breaker.

Guess what happened? Buzz Aldrin, while reentering the LM from the spacewalk. This meant that, well, they couldn't push the breaker back in, and if they couldn't do something about it, the engine it powered wouldn't fire. That engine? The ascent engine.

Oops.

After carefully looking, the crew realized that the handle was broken, but the breaker itself was fine. So, during the countdown to lunar ascent, when the item to close the ascent engine breaker came up, Buzz pushed it closed using the tip of a Duro felt-tip pen. No, not the AG-7 pen, despite the claims of the Fisher pen company.

Obviously, it worked.

Great post, Brandon Blatcher.
posted by eriko at 4:21 PM on July 21 [11 favorites]


Still sad about Apollos 18-20. Everything had been built, the missions planned, the science scoped out. The money had been spent already: canning the missions saved around $50 million. There is an argument that the returns weren't worth risking the lives of the astronauts for - but I doubt the astronauts thought that. After all, how many lives got lost taking a hill in Vietnam?

If you want a point when the Apollo spirit left the VAB - it was that cancellation.
posted by Devonian at 4:32 PM on July 21 [9 favorites]


On July 21st 1969, my family lived right on the lake, Lake Huron, in Port Austin MI. We had a big back yard bbq that day in celebration, and also as a going away party as we were moving in two days (on my birthday) back to suburban Phila. The old man was in the Air Force and he was being reassigned. I remember my old man, stopping between cooking to watch what we could see in a little portable b&w tv. Everything stopped for that one moment when the LM finally landed on the moon. It was an amazing moment for all of us and I've always thought of it as sort of a birthday present. Certainly a better present than I normally got. Miles above the present of moving on my birthday. Days later, in my grandparents kitchen, the old man gave me a present, a model of the moon landing (Revell, I think). It was honestly, a let down, and a prelude to how that next year would be.
posted by evilDoug at 4:39 PM on July 21 [2 favorites]


Somehow I've been on Earth 40+ years and I have yet to see a human on the moon.
posted by humanfont at 4:53 PM on July 21 [6 favorites]




We talked about this anniversary last night, with my 86-year-old retired mechanical engineer dad. He worked at NASA subcontractor, designing gyros, and the night Armstrong landed on the moon, Dad was in a clean room, building a new gyroscope to be used on a future Apollo mission.

He has a bunch of Apollo mission patches from his 30+ years there, and one of my projects for this summer is to get them mounted and framed so he can finally show them off (he kept them in a drawer for the last 40 years...).
posted by suelac at 4:55 PM on July 21 [4 favorites]


Blowing it up is the other half, right?
posted by Fizz at 4:57 PM on July 21 [3 favorites]


eriko, do you have a cite for the CSM being specced for direct ascent? I understand that was the idea in use until quite late, but the design of the CSM, with docking hatch on the front and lack of provisions for landing, suggests LOR was the plan by the time it was designed. Or did you mean the SPS predates that design?
posted by thegears at 5:01 PM on July 21


A long time ago I did some work in Florida near Cape Canaveral, with some ex-NASA engineers who had worked on the control software for the main launch sequence back in the 70s. We went out for drinks one night and they spent a couple of hours explaining to me how they never knew if anything was actually going to work, every single moment of every launch.

The one story I remember was about the software that controlled exploding the bolts to detach the rocket from the launch tower. They designed it to send the order to explode the bolts, then check that the rocket was in fact free of the tower, and then send the ignition order to the main engine. If for some reason the bolts failed to explode, then they couldn't send the ignition order, because otherwise the rocket would destroy the tower, launch off in an unknown direction, and crash in a ugly fireball.

They first tested the software without actually firing the rocket. They discovered that the check that the bolts had detached from the tower took so long that the rocket started to fall over on the launch pad before they could send the ignition order. The only solution they could come up with was to remove the check, cross their fingers, and hope they didn't get the fireball.

It's amazing that they pulled off the moon landing with the technology they had at the time.
posted by fuzz at 5:02 PM on July 21 [10 favorites]




I'm reading this post on a phone that had more computing power then was available to the entire Apollo program.
posted by COD at 5:08 PM on July 21 [11 favorites]


There were minor, human related problems that caused the LM to veer wildly out of control as it ascended from the 50K mark, causing one of the astronauts to exclaim "Son of Bitch" over the open air mic and eventually having to apologize for it due to complaints.

Does "well, for a moment there it looked like we were either going to crash uncontrollably into the moon and die or fly uncontrollably off into space and die, so anyone who was offended can go fuck themselves" count as an apology?

Man, I hope we send a human to Mars in my lifetime, even if it's the Mars reality show that gets there first.
posted by Blue Jello Elf at 5:18 PM on July 21 [3 favorites]


The whole Apollo program fills me with such happiness. WE. WENT. UP. THERE. It's awful that NASA is underfunded at the moment, but we'll go again, they can't stop human curiosity. Oh, the places we will go.
posted by arcticseal at 5:19 PM on July 21 [4 favorites]


It's amazing that they pulled off the moon landing with the technology they had at the time.

Absolutely. If you go to the Smithsonian and look at the (spare unit) lunar module they have on display, it looks like it's put together with duct tape and baling wire, with parts of it wrapped in a bunch of gold-colored aluminum foil. It took some guts to get in that thing and fly to the moon. I have a similar reaction to the Rube Goldberg-like way the latest Mars missions landed, with a combination of parachutes, retrorockets and airbags.
posted by beagle at 5:21 PM on July 21 [4 favorites]


the gears: the SPS predates the CSM/LM because in a direct ascent scenario, you don't need the CSM/LM split. When the LOR rendezvous was chosen, a lot of mass was cut off the CSM, but they weren't willing to rebuild the SPS. It was (now) too large, but it would work.

Those who don't think a CSM/SPS combo couldn't land on the moon are welcome to try it in Kerbal Space Program. The problem with Direct ascent was boosting a CSM that had enough fuel to land, then take off. In KSP sandbox mode, the ΔV is free.

The Nova program was the program that was going to boost a direct ascent CSM to the moon. The switch to LOR meant that a "smaller" booster -- mind you, still the largest booster ever built -- could be built.

The indirect side effect of the LOR decision: If Apollo 11 was a direct ascent mission, Micheal Collins would have been the 2nd or 3rd man on the moon.
posted by eriko at 5:29 PM on July 21 [1 favorite]


I like how this project was basically like any other enormous project, multiple simultaneous small fires to put out continuously for ten years.
posted by Captain Chesapeake at 5:41 PM on July 21 [4 favorites]


When I was ten, just over a decade after Apollo 11, I got a book called Our Universe that was put out by the National Geographic Society. I really thought we were going to explore the Solar system in my lifetime. I figured we'd be going to Mars before I was an adult.

In my late teens, I would watch Beyond 2000 and still believe we would explore the Solar system in my lifetime.

Now I'm approaching middle-age, and my hope is fading, but it's not gone.

Every time I hear rumors about we're going to land on an asteroid or we're going back to the Moon, or we're going to Mars, my heart skips a beat. Maybe this will be it. Maybe we'll finally start working on what should have been going on my entire lifetime.

That, more than anything else, is the true power of the Apollo program. It's too bad the people who make the decisions never felt that way.


P.S. Outstanding post, Brandon.
posted by ob1quixote at 5:55 PM on July 21 [12 favorites]


In the immediate afterglow growing up back then you would often stop what you were doing to just look up at the moon, and smile, and get on with ANY task at hand.

Whatever happened to us?
posted by hal9k at 5:55 PM on July 21 [3 favorites]


Tom Kelly wrote a great memoir, Moon Lander: How We Developed the Apollo Lunar Module. He was tremendously proud of what Grumman did, but glad to see Apollo cancelled - he was convinced that astronaut deaths were only a matter of time.
posted by djb at 6:22 PM on July 21


My grandfather went to work at Grumman when he was 18 and retired at 58 when they delivered the prototype F-14. He started there when they were still in Farmingdale and met my grandmother there during the war. He was running the one-off machine shop during his last years there so he did a lot of the literal nuts and bolts of the first versions of the LEM. My Aunt actually has an album of pictures of him and his buddies working on it.
posted by JPD at 6:33 PM on July 21 [1 favorite]


Uncle Sam only went there to show up the communists. Once the Cold War ended, it just wasn't a priority anymore. The only way we dare go back up there is when the Taikonauts make a stab at a permanent moonbase, only to show them up.

That's all exploration is, just showing up foreign competitors and rubbing their noses in it.
posted by Renoroc at 6:48 PM on July 21 [1 favorite]


Reading this post, though, (and I did, every word from top to bottom), makes me reconsider my assumption about MF's purpose. Maybe telling an interesting story in a compelling manner, and using links to back up claims and flesh out the details, is a legit way of creating an FPP.

It totally is and if there's a particular story in a subject that you love, do share it with us.

The creation of this post is an act of love. I'm not engineer, nor have I ever worked for NASA in any capacity. But I love reading about manned spaceflight, Apollo in particular and have come across some amazing stories about the program, the people and the missions. I want to share those with everyone because they are so fucking cool and inspiring. They speak to the very best in humanity and everyone should know!

Plus, as person who's seen and read a lot of scifi, I'm keenly aware that the Lunar Module is, so far, humanity's only "real" manned spaceship (meaning it was designed to operate solely in space). The reality vs the fantasy is humbling.

Thanks eriko for including the story about breaking the handle on the ignition button. I wanted to include that, but the post was already freakishly long, so one has to cut some things.

Still sad about Apollos 18-20.I'm reading this post on a phone that had more computing power then was available to the entire Apollo program.

A phone from the '90s had more power than the Apollo LM. Consider how underpowered those were! We could probably run an armada with the processing power currently available.

Tom Kelly wrote a great memoir, Moon Lander: How We Developed the Apollo Lunar Module. He was tremendously proud of what Grumman did, but glad to see Apollo cancelled - he was convinced that astronaut deaths were only a matter of time.

Kelly's book is really good, if a little dry, but he really gets into some of the technical problems and problems solving they had to do. Hghly recommended if you want to dig more into the subject.

Other bits of info swirling around in my head at the moment:

Once the Apollo 11 Ascent Module docked with the CSM in lunar orbit and the astronauts transferred to it, they naturally jettisoned the LM. But they did left all the systems running, as if people were still in it, except for the cooling system. NASA wanted to know how long an LM could run with no cooling. The answer was about 8 hours and evidently this info was useful keeping the astronauts alive on the Apollo 13 mission.

--

The Apollo 13 explosion was ultimately due to a screwup in the Service Module design and construction. The electrical system was originally 28 volts, then changed to 65 volts. But somehow, the actual change wasn't actually made and no one caught the mistake. Every mission up to 13 flew with that mistake, but it was unique set of circumstances that exposed the error on that mission.

--

Those paper thin walls on the LM? Supposedly a worker dropped a screwdriver on the LM and it punctured the wall.
On Apollo 10, after the CSM and LM had undocked, the Command Module Pilot (John Young) saw the walls of the LM flexng from being pressurized. That freaked him out a bit, heh. Not enough to skip commanding Apollo 16 though!

--
After Apollo 11 landed, Tom Kelly and other engineers were monitoring a pressure build up in the Descent Module. Had it continued, it would not have been a good day. But eventually it went back down, probably due to a frozen chunk of fuel blocking the line, which eventually melted.

--
Kerbal Space Program is ridiculously educational on how dangerous and difficult launching rockets and landing on other planets. Highly recommended.
posted by Brandon Blatcher at 6:49 PM on July 21 [11 favorites]


I was 16 or so when this happened. I watched it on a tiny B&W TV on my friend's grandmother's kitchen table. I drove home ecstatically, up and down the rolling hills of suburban St. Louis, looking up at the moon, shouting to myself: There are human beings up there, on the Moon! Damn!
posted by kozad at 7:13 PM on July 21 [4 favorites]


And as if enough hasn't been said about Kerbal Space Program in this thread, KSP is currently on sale on steam for $16.
posted by nathan_teske at 7:24 PM on July 21 [1 favorite]


Perhaps, several thousands years from now, the various space traveling transhuman species will believe that the universal timestamp counts the number of seconds since man first walked on the moon, rather than the arbitrary epoch date of 01970-01-01.
That's only fourteen million seconds difference, which hardly matters at that scale anyway...
posted by autopilot at 8:53 PM on July 21 [3 favorites]


I posted this comment a couple years ago in this thread-

I was a project engineer at NASA during this time- Marshall Space Flight Center, Huntsville. Worked on the J-2 rocket engine project (2nd and 3rd stages of the Saturn V). Those were heady times indeed, and it's truly amazing what was accomplished less than seventy years after the first powered flight.
I was lucky enough to be in the blockhouse for the first launch of the Saturn V. Nov 7, 1967. Young engineer, just out of college the previous June.

Get off my lawn.
posted by drhydro at 10:29 PM on July 21 [15 favorites]


This is very nifty. But. July 21th? Shouldn't it be 21st? Am I missing an obvious joke?
posted by dotgirl at 11:27 PM on July 21 [1 favorite]


Many years ago, I had the opportunity to attend a dinner wherein James Burke was a guest speaker. In his talk he mentioned (and this stuck with me) that the NASA program for the moon landing was extremely economical. He claimed that during the same time, more money was spent on lipstick. He also claimed that one of the biggest challenges was not technical, but organizational because of the sheer number of people involved who had to coordinate and communicate.
posted by plinth at 3:11 AM on July 22 [1 favorite]


The Apollo 13 explosion was ultimately due to a screwup in the Service Module design and construction. The electrical system was originally 28 volts, then changed to 65 volts. But somehow, the actual change wasn't actually made and no one caught the mistake.

As I understand it, the SM always had a 28V electrical system, as did the CM. However, ground-based test equipment used for, among other things, testing the oxygen tanks, ran of 65V, and the cryogenic tanks were not properly upgraded for this:

Inside each O2 tank there was a thermostat-controlled switch that would automatically turn off the heating element inside the tank (normally used to heat up liquid oxygen until it started to boil, so it could be extracted from the tank, bit by bit) in the event the tank temperature reached 80 degrees C. This component was not upgraded to withstand 65V.

On the eve of the installation of oxygen tank 2 into 13's SM, the tank had been dropped on the ground, damaging a internal line/vent that was to be used to remove oxygen after the tank was tested before the flight. Since the ground engineers were unable to vent the tank normally, they opted to leave the tank's heaters on until the oxygen vented, trusting that the heating element would turn off when this was complete (because of the thermostat).

However, the thermostatic switch instead welded shut, and the innards of the tank were exposed to temperatures believed to be higher than 1000 degrees C, likely destroying electrical insulation of other electrical components inside the tank, allowing for a short that caused the explosion even when running on the 28V all the components had been designed for.
posted by thegears at 4:22 AM on July 22 [5 favorites]


Oh, and meant to put the link in to the NASA report.
posted by thegears at 4:23 AM on July 22


To do this, engineers had to radically rethink every idea on how to fly and land a ship, as demonstrated in this clip on LM design from episode nine of HBO's mini series from the Earth to the Moon.

I cannot recommend this series enough. It is unfortunately not part of the HBO series available on Amazon Prime Streaming, but the DVD set is relatively cheap.

About once a year I pull it off the shelf, give it another watch and think wistfully about my childhood dreams of being an astronaut. The theme song brings a tear to my eye.
posted by Fleebnork at 5:34 AM on July 22 [2 favorites]


The National Security Archive published: Soldiers, Spies and the Moon: Secret U.S. and Soviet Plans from the 1950s and 1960s
The posting includes:

  • Army and Air Force studies from 1959 - 1961 on the creation of a military lunar base, with possible uses as a surveillance platform (for targets on earth and space) and the Lunar Based Earth Bombardment System (Document 1a, Document 1b, Document 3, Document 4).
  • A study on the detonation of a nuclear device on or in the vicinity of the moon (Document 2).
  • The use of the lunar surface to relay signals from Washington to Hawaii and from U.S. spy ships (Document 15).
  • Collection of Soviet radar signals after they bounced off the moon — a technique known as Moon Bounce ELINT (Document 11, Document 14).
  • The U.S. theft and return of a Soviet space capsule during an exhibition tour (Document 13).
  • A 1965 estimate of Soviet intentions with regard to a manned moon landing (Document 5).
  • Several analyses of Soviet Luna missions, including Luna 9 — the first mission to result in a soft landing on the moon (Document 6, Document 7, Document 8, Document 10, Document 16).
  • posted by shothotbot at 7:14 AM on July 22 [1 favorite]


    > "The LM had continued performing as well as before"

    Not precisely. Worth re-linking to Don Eyles' harrowing tale of two control tuning and software bugs that caused the computer to shed load several times during descent and had Armstrong's pulse rate at 200bpm on final approach.

    The bugs almost led to the crash of Apollo 11's lunar lander. The outcome spawned decades of work into human "mental workload". Armstrong was pretty much at the limits of human ability in sticking that first landing without computer assistance.
    posted by anthill at 7:32 AM on July 22 [7 favorites]


    Oh wow! I thought the landing alarms were more symbolic and a result of a faulty checklist and switch setting, so more human error than the LM per se. Not quite. Interesting stuff, thanks.
    posted by Brandon Blatcher at 8:21 AM on July 22


    With all modesty, it appears to be the case that if the author had coded the "correct" compensation number in the throttle-control routine, Apollo 11 would not have landed. I invite someone with no personal stake and a grasp of the mathematics to reexamine this theory.

    Sweet Jesus.
    posted by JoeZydeco at 9:43 AM on July 22 [1 favorite]


    (Well, that's a fabulous megapost, and the comments are another mine of information. Too bad about those deadlines I guess.)
    posted by RedOrGreen at 9:53 AM on July 22


    We may have more computing power now versus the Apollo days, but most of what they were using was designed specifically for the task at hand. A general purpose computer with a general purpose interface has different constraints over what amounts to firmware.
    posted by ZeusHumms at 10:00 AM on July 22


    The only surviving flown Ascent module is from Apollo 10, code named Snoopy. It was jettisoned after the astronauts returned to the CSM and is in an unknown orbit around the sun.

    As a Peanuts fan I think this is so cool -- Snoopy's still out there among stars, sitting on top of his doghouse, wearing his space helmet and cursing the Red Baron.
    posted by Rash at 10:27 AM on July 22 [5 favorites]


    A general purpose computer with a general purpose interface has different constraints over what amounts to firmware.

    Firmware that was woven by hand.
    posted by JoeZydeco at 10:32 AM on July 22 [2 favorites]


    Something tells me that our return to the moon will be like the [surviving] Beatles reunion on the 50th anniversary of the Ed Sullivan Show debut: It just won't be the same. You can't do something first again.

    So yeah, can we please not blow up the moon?
    posted by yoga at 12:58 PM on July 22


    We may have more computing power now versus the Apollo days, but most of what they were using was designed specifically for the task at hand. A general purpose computer with a general purpose interface has different constraints over what amounts to firmware.

    True enough, although it would be very easy to find embedded systems to power the same kind of operations today, although that's not counting radiation shielding.

    In any case, the software that ran on the AGCs was pretty remarkable in its design, especially for the era. Preemptive multitasking, microcode, and a pretty sane user interface are not exactly common factors of small (well, less-big) computers of the 1960s.
    posted by thegears at 3:04 PM on July 22


    So yeah, can we please not blow up the moon?

    Since the beginning of time Mankind has yearned to destroy the sun. I shall do the next best thing: block it ou.... I mean, blow up the moon!
    posted by aramaic at 3:13 PM on July 22 [1 favorite]


    Moondoggle: The Forgotten Opposition To The Apollo Program
    Today, we recall the speech John F. Kennedy made 50 years ago as the beginning of a glorious and inexorable process in which the nation united behind the goal of a manned lunar landing even as the presidency swapped between parties. Time has tidied things up.

    Polls both by USA Today and Gallup have shown support for the moon landing has increased the farther we've gotten away from it. 77 percent of people in 1989 thought the moon landing was worth it; only 47 percent felt that way in 1979.

    When Neil Armstrong and Buzz Aldrin landed on the moon, a process began that has all but eradicated any reference to the substantial opposition by scientists, scholars, and regular old people to spending money on sending humans to the moon. Part jobs program, part science cash cow, the American space program in the 1960s placed the funding halo of military action on the heads of civilians. It bent the whole research apparatus of the United States to a symbolic goal in the Cold War.

    This chart from the Congressional Research Service shows just how extreme the Space Race's funding levels were, even in comparison to the Manhattan Project or the brief fluorescence of energy R&D after the OPEC oil embargo of 1973.
    posted by the man of twists and turns at 4:46 PM on July 22 [3 favorites]


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